[Tests] Increase QMK test coverage (#13789)

* Add per-test keymaps

* Add better trace and info logs for failed unit-tests

* Add layer state assertion with tracing message

* Use individual test binaries configuration options

* Add basic qmk functionality tests

* Add tap hold configurations tests

* Add auto shift tests

* `qmk format-c

* Fix tests

Co-authored-by: Nick Brassel <nick@tzarc.org>

49 files changed, 2688 insertions, 265 deletions

diff --git a/Makefile b/Makefile
index c221cb89e0..88f430619e 100644
--- a/Makefile
+++ b/Makefile
@@ -378,11 +378,12 @@ define PARSE_ALL_KEYMAPS
 endef
 
 define BUILD_TEST
-    TEST_NAME := $1
+    TEST_PATH := $1
+    TEST_NAME := $$(notdir $$(TEST_PATH))
     MAKE_TARGET := $2
     COMMAND := $1
     MAKE_CMD := $$(MAKE) -r -R -C $(ROOT_DIR) -f build_test.mk $$(MAKE_TARGET)
-    MAKE_VARS := TEST=$$(TEST_NAME) FULL_TESTS="$$(FULL_TESTS)"
+    MAKE_VARS := TEST=$$(TEST_NAME) TEST_PATH=$$(TEST_PATH) FULL_TESTS="$$(FULL_TESTS)"
     MAKE_MSG := $$(MSG_MAKE_TEST)
     $$(eval $$(call BUILD))
     ifneq ($$(MAKE_TARGET),clean)
@@ -406,7 +407,7 @@ define PARSE_TEST
     ifeq ($$(TEST_NAME),all)
         MATCHED_TESTS := $$(TEST_LIST)
     else
-        MATCHED_TESTS := $$(foreach TEST,$$(TEST_LIST),$$(if $$(findstring $$(TEST_NAME),$$(TEST)),$$(TEST),))
+        MATCHED_TESTS := $$(foreach TEST, $$(TEST_LIST),$$(if $$(findstring $$(TEST_NAME), $$(notdir $$(TEST))), $$(TEST),))
     endif
     $$(foreach TEST,$$(MATCHED_TESTS),$$(eval $$(call BUILD_TEST,$$(TEST),$$(TEST_TARGET))))
 endef
diff --git a/build_full_test.mk b/build_full_test.mk
index f8030cb060..4cd1ac61b5 100644
--- a/build_full_test.mk
+++ b/build_full_test.mk
@@ -13,21 +13,24 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-#include $(TMK_PATH)/protocol.mk
+$(TEST)_INC := \
+	tests\test_common\common_config.h
 
-TEST_PATH=tests/$(TEST)
-
-$(TEST)_SRC= \
-	$(TEST_PATH)/keymap.c \
+$(TEST)_SRC := \
 	$(TMK_COMMON_SRC) \
 	$(QUANTUM_SRC) \
 	$(SRC) \
+	tests/test_common/keymap.c \
 	tests/test_common/matrix.c \
 	tests/test_common/test_driver.cpp \
 	tests/test_common/keyboard_report_util.cpp \
-	tests/test_common/test_fixture.cpp
-$(TEST)_SRC += $(patsubst $(ROOTDIR)/%,%,$(wildcard $(TEST_PATH)/*.cpp))
+	tests/test_common/test_fixture.cpp \
+	tests/test_common/test_keymap_key.cpp \
+	tests/test_common/test_logger.cpp \
+	$(patsubst $(ROOTDIR)/%,%,$(wildcard $(TEST_PATH)/*.cpp))
+
+$(TEST)_DEFS := $(TMK_COMMON_DEFS) $(OPT_DEFS)
+
+$(TEST)_CONFIG := $(TEST_PATH)/config.h
 
-$(TEST)_DEFS=$(TMK_COMMON_DEFS) $(OPT_DEFS)
-$(TEST)_CONFIG=$(TEST_PATH)/config.h
-VPATH+=$(TOP_DIR)/tests/test_common
+VPATH += $(TOP_DIR)/tests/test_common
\ No newline at end of file
diff --git a/build_test.mk b/build_test.mk
index 36cb7936ed..136a0455f0 100644
--- a/build_test.mk
+++ b/build_test.mk
@@ -16,14 +16,14 @@ TEST_OBJ = $(BUILD_DIR)/test_obj
 OUTPUTS := $(TEST_OBJ)/$(TEST) $(GTEST_OUTPUT)
 
 GTEST_INC := \
-	$(LIB_PATH)/googletest/googletest/include\
-	$(LIB_PATH)/googletest/googlemock/include\
+	$(LIB_PATH)/googletest/googletest/include \
+	$(LIB_PATH)/googletest/googlemock/include
 
-GTEST_INTERNAL_INC :=\
-	$(LIB_PATH)/googletest/googletest\
+GTEST_INTERNAL_INC := \
+	$(LIB_PATH)/googletest/googletest \
 	$(LIB_PATH)/googletest/googlemock
 
-$(GTEST_OUTPUT)_SRC :=\
+$(GTEST_OUTPUT)_SRC := \
 	googletest/src/gtest-all.cc\
 	googlemock/src/gmock-all.cc
 
@@ -33,9 +33,9 @@ $(GTEST_OUTPUT)_INC := $(GTEST_INC) $(GTEST_INTERNAL_INC)
 LDFLAGS += -lstdc++ -lpthread -shared-libgcc
 CREATE_MAP := no
 
-VPATH +=\
-	$(LIB_PATH)/googletest\
-	$(LIB_PATH)/googlemock\
+VPATH += \
+	$(LIB_PATH)/googletest \
+	$(LIB_PATH)/googlemock \
 	$(LIB_PATH)/printf
 
 all: elf
@@ -49,7 +49,8 @@ CONSOLE_ENABLE = yes
 endif
 
 ifneq ($(filter $(FULL_TESTS),$(TEST)),)
-include tests/$(TEST)/rules.mk
+include tests/test_common/build.mk
+include $(TEST_PATH)/test.mk
 endif
 
 include common_features.mk
diff --git a/quantum/quantum_keycodes.h b/quantum/quantum_keycodes.h
index d013a6a169..cde97074d3 100644
--- a/quantum/quantum_keycodes.h
+++ b/quantum/quantum_keycodes.h
@@ -558,40 +558,6 @@ enum quantum_keycodes {
     PROGRAMMABLE_BUTTON_31,
     PROGRAMMABLE_BUTTON_32,
 
-    // Dedicated macro keys for Configurator and VIA
-    MACRO_0,
-    MACRO_1,
-    MACRO_2,
-    MACRO_3,
-    MACRO_4,
-    MACRO_5,
-    MACRO_6,
-    MACRO_7,
-    MACRO_8,
-    MACRO_9,
-    MACRO_10,
-    MACRO_11,
-    MACRO_12,
-    MACRO_13,
-    MACRO_14,
-    MACRO_15,
-    MACRO_16,
-    MACRO_17,
-    MACRO_18,
-    MACRO_19,
-    MACRO_20,
-    MACRO_21,
-    MACRO_22,
-    MACRO_23,
-    MACRO_24,
-    MACRO_25,
-    MACRO_26,
-    MACRO_27,
-    MACRO_28,
-    MACRO_29,
-    MACRO_30,
-    MACRO_31,
-
     // Start of custom keycode range for keyboards and keymaps - always leave at the end
     SAFE_RANGE
 };
diff --git a/testlist.mk b/testlist.mk
index cff784dad6..d2bb571be6 100644
--- a/testlist.mk
+++ b/testlist.mk
@@ -1,5 +1,5 @@
-TEST_LIST = $(notdir $(patsubst %/rules.mk,%,$(wildcard $(ROOT_DIR)/tests/*/rules.mk)))
-FULL_TESTS := $(TEST_LIST)
+TEST_LIST = $(sort $(patsubst %/test.mk,%, $(shell find $(ROOT_DIR)tests -type f -name test.mk)))
+FULL_TESTS := $(notdir $(TEST_LIST))
 
 include $(QUANTUM_PATH)/debounce/tests/testlist.mk
 include $(QUANTUM_PATH)/encoder/tests/testlist.mk
diff --git a/tests/auto_shift/config.h b/tests/auto_shift/config.h
new file mode 100644
index 0000000000..4f343b4529
--- /dev/null
+++ b/tests/auto_shift/config.h
@@ -0,0 +1,19 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "test_common.h"
\ No newline at end of file
diff --git a/tests/auto_shift/test.mk b/tests/auto_shift/test.mk
new file mode 100644
index 0000000000..4259c606e4
--- /dev/null
+++ b/tests/auto_shift/test.mk
@@ -0,0 +1,20 @@
+# Copyright 2021 Stefan Kerkmann
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# --------------------------------------------------------------------------------
+# Keep this file, even if it is empty, as a marker that this folder contains tests
+# --------------------------------------------------------------------------------
+
+AUTO_SHIFT_ENABLE = yes
\ No newline at end of file
diff --git a/tests/auto_shift/test_auto_shift.cpp b/tests/auto_shift/test_auto_shift.cpp
new file mode 100644
index 0000000000..9c5ed9a832
--- /dev/null
+++ b/tests/auto_shift/test_auto_shift.cpp
@@ -0,0 +1,73 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "keyboard_report_util.hpp"
+#include "keycode.h"
+#include "test_common.hpp"
+#include "action_tapping.h"
+#include "test_fixture.hpp"
+#include "test_keymap_key.hpp"
+
+using testing::_;
+using testing::InSequence;
+
+class AutoShift : public TestFixture {};
+
+TEST_F(AutoShift, key_release_before_timeout) {
+    TestDriver driver;
+    InSequence s;
+    auto       regular_key = KeymapKey(0, 2, 0, KC_A);
+
+    set_keymap({regular_key});
+
+    /* Press regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_A)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    regular_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(AutoShift, key_release_after_timeout) {
+    TestDriver driver;
+    InSequence s;
+    auto       regular_key = KeymapKey(0, 2, 0, KC_A);
+
+    set_keymap({regular_key});
+
+    /* Press regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.press();
+    idle_for(AUTO_SHIFT_TIMEOUT);
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSFT, KC_A)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSFT)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    regular_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
\ No newline at end of file
diff --git a/tests/basic/config.h b/tests/basic/config.h
index 99bd62d991..85fa9d691d 100644
--- a/tests/basic/config.h
+++ b/tests/basic/config.h
@@ -16,5 +16,4 @@
 
 #pragma once
 
-#define MATRIX_ROWS 4
-#define MATRIX_COLS 10
+#include "test_common.h"
\ No newline at end of file
diff --git a/tests/basic/keymap.c b/tests/basic/keymap.c
deleted file mode 100644
index 2b5747abb7..0000000000
--- a/tests/basic/keymap.c
+++ /dev/null
@@ -1,45 +0,0 @@
-/* Copyright 2017 Fred Sundvik
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include "quantum.h"
-
-// Don't rearrange keys as existing tests might rely on the order
-// Col2, Row 0 has to be KC_NO, because tests rely on it
-
-#define COMBO1 RSFT(LCTL(KC_O))
-
-const uint16_t PROGMEM
-               keymaps[][MATRIX_ROWS][MATRIX_COLS] =
-        {
-            [0] =
-                {
-                    // 0    1      2      3        4        5        6       7            8      9
-                    {KC_A, KC_B, KC_NO, KC_LSFT, KC_RSFT, KC_LCTL, COMBO1, SFT_T(KC_P), M(0), KC_NO},
-                    {KC_EQL, KC_PLUS, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO},
-                    {KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO},
-                    {KC_C, KC_D, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO},
-                },
-};
-
-const macro_t *action_get_macro(keyrecord_t *record, uint8_t id, uint8_t opt) {
-    if (record->event.pressed) {
-        switch (id) {
-            case 0:
-                return MACRO(D(LSFT), T(H), U(LSFT), T(E), T(L), T(L), T(O), T(SPACE), W(100), D(LSFT), T(W), U(LSFT), I(10), T(O), T(R), T(L), T(D), D(LSFT), T(1), U(LSFT), END);
-        }
-    }
-    return MACRO_NONE;
-};
diff --git a/tests/basic/test.mk b/tests/basic/test.mk
new file mode 100644
index 0000000000..29690d1adf
--- /dev/null
+++ b/tests/basic/test.mk
@@ -0,0 +1,18 @@
+# Copyright 2017 Fred Sundvik
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# --------------------------------------------------------------------------------
+# Keep this file, even if it is empty, as a marker that this folder contains tests
+# --------------------------------------------------------------------------------
\ No newline at end of file
diff --git a/tests/basic/test_action_layer.cpp b/tests/basic/test_action_layer.cpp
index d00a0859b9..1b12d13642 100644
--- a/tests/basic/test_action_layer.cpp
+++ b/tests/basic/test_action_layer.cpp
@@ -14,39 +14,54 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include "gtest/gtest.h"
+#include "keyboard_report_util.hpp"
 #include "test_common.hpp"
 
 using testing::_;
-using testing::Return;
+using testing::InSequence;
 
 class ActionLayer : public TestFixture {};
 
-// TEST_F(ActionLayer, LayerStateDBG) {
-//     layer_state_set(0);
-// }
-
-// TEST_F(ActionLayer, LayerStateSet) {
-//     layer_state_set(0);
-//     EXPECT_EQ(layer_state, 0);
-//     layer_state_set(0b001100);
-//     EXPECT_EQ(layer_state, 0b001100);
-// }
-
-// TEST_F(ActionLayer, LayerStateIs) {
-//     layer_state_set(0);
-//     EXPECT_EQ(layer_state_is(0), true);
-//     EXPECT_EQ(layer_state_is(1), true);
-//     layer_state_set(1);
-//     EXPECT_EQ(layer_state_is(0), true);
-//     EXPECT_EQ(layer_state_is(1), true);
-//     layer_state_set(2);
-//     EXPECT_EQ(layer_state_is(0), false);
-//     EXPECT_EQ(layer_state_is(1), false);
-//     EXPECT_EQ(layer_state_is(2), true);
-// }
+TEST_F(ActionLayer, LayerStateDBG) {
+    TestDriver driver;
+
+    layer_state_set(0);
+
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(ActionLayer, LayerStateSet) {
+    TestDriver driver;
+
+    layer_state_set(0);
+    EXPECT_EQ(layer_state, 0);
+    layer_state_set(0b001100);
+    EXPECT_EQ(layer_state, 0b001100);
+
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(ActionLayer, LayerStateIs) {
+    TestDriver driver;
+
+    layer_state_set(0);
+    EXPECT_EQ(layer_state_is(0), true);
+    EXPECT_EQ(layer_state_is(1), false);
+    layer_state_set(1);
+    EXPECT_EQ(layer_state_is(0), true);
+    EXPECT_EQ(layer_state_is(1), false);
+    layer_state_set(2);
+    EXPECT_EQ(layer_state_is(0), false);
+    EXPECT_EQ(layer_state_is(1), true);
+    EXPECT_EQ(layer_state_is(2), false);
+
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
 
 TEST_F(ActionLayer, LayerStateCmp) {
-    uint32_t prev_layer;
+    TestDriver driver;
+    uint32_t   prev_layer;
 
     prev_layer = 0;
     EXPECT_EQ(layer_state_cmp(prev_layer, 0), true);
@@ -60,33 +75,339 @@ TEST_F(ActionLayer, LayerStateCmp) {
     EXPECT_EQ(layer_state_cmp(prev_layer, 0), false);
     EXPECT_EQ(layer_state_cmp(prev_layer, 1), true);
     EXPECT_EQ(layer_state_cmp(prev_layer, 2), false);
+
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(ActionLayer, LayerClear) {
+    TestDriver driver;
+
+    layer_clear();
+    EXPECT_EQ(layer_state, 0);
+
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(ActionLayer, LayerMove) {
+    TestDriver driver;
+
+    layer_move(0);
+    EXPECT_EQ(layer_state, 1);
+    layer_move(3);
+    EXPECT_EQ(layer_state, 0b1000);
+
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(ActionLayer, LayerOn) {
+    TestDriver driver;
+
+    layer_clear();
+    layer_on(1);
+    layer_on(3);
+    layer_on(3);
+    EXPECT_EQ(layer_state, 0b1010);
+
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(ActionLayer, LayerOff) {
+    TestDriver driver;
+
+    layer_clear();
+    layer_on(1);
+    layer_on(3);
+    layer_off(3);
+    layer_off(2);
+    EXPECT_EQ(layer_state, 0b0010);
+
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(ActionLayer, MomentaryLayerDoesNothing) {
+    TestDriver driver;
+    KeymapKey  layer_key = KeymapKey{0, 0, 0, MO(1)};
+
+    set_keymap({layer_key});
+
+    /* Press and release MO, nothing should happen. */
+    /* TODO: QMK currently sends an empty report even if nothing needs to be reported to the host! */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(1);
+    layer_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* TODO: QMK currently sends an empty report even if nothing needs to be reported to the host! */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(1);
+    layer_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(ActionLayer, MomentaryLayerWithKeypress) {
+    TestDriver driver;
+    KeymapKey  layer_key = KeymapKey{0, 0, 0, MO(1)};
+
+    /* These keys must have the same position in the matrix, only the layer is different. */
+    KeymapKey regular_key = KeymapKey{0, 1, 0, KC_A};
+    set_keymap({layer_key, regular_key, KeymapKey{1, 1, 0, KC_B}});
+
+    /* Press MO. */
+    /* TODO: QMK currently sends an empty report even if nothing needs to be reported to the host! */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(1);
+    layer_key.press();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press key on layer 1 */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_B))).Times(1);
+    regular_key.press();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release key on layer 1 */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(1);
+    regular_key.release();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release MO */
+    /* TODO: QMK currently sends an empty report even if nothing needs to be reported to the host! */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(1);
+    layer_key.release();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(0));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(ActionLayer, ToggleLayerDoesNothing) {
+    GTEST_SKIP() << "TODO: Toggle layer does not activate the expected layer on key press but on release.";
+
+    TestDriver driver;
+    KeymapKey  layer_key = KeymapKey{0, 0, 0, TG(1)};
+
+    set_keymap({layer_key});
+
+    /* Press TG. Layer state should not change as it's applied on release. */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    layer_key.press();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release TG. */
+    /* TODO: QMK currently sends an empty report even if nothing needs to be reported to the host! */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(1);
+    layer_key.release();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(ActionLayer, ToggleLayerUpAndDown) {
+    GTEST_SKIP() << "TODO: Toggle layer does not activate the expected layer on key press but on release.";
+
+    TestDriver driver;
+    KeymapKey  toggle_layer_1_on_layer_0 = KeymapKey{0, 0, 0, TG(1)};
+    KeymapKey  toggle_layer_0_on_layer_1 = KeymapKey{1, 1, 0, TG(0)};
+
+    set_keymap({toggle_layer_1_on_layer_0, toggle_layer_0_on_layer_1});
+
+    /* Toggle Layer 1. */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    toggle_layer_1_on_layer_0.press();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* TODO: QMK currently sends an empty report even if nothing needs to be reported to the host! */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(1);
+    toggle_layer_1_on_layer_0.release();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Toggle Layer 0. */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    toggle_layer_0_on_layer_1.press();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(0));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* TODO: QMK currently sends an empty report even if nothing needs to be reported to the host! */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(1);
+    toggle_layer_0_on_layer_1.release();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(0));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(ActionLayer, LayerTapToggleDoesNothing) {
+    GTEST_SKIP() << "TODO: Tap toggle layer does not activate the expected layer on key press.";
+
+    TestDriver driver;
+    KeymapKey  layer_key = KeymapKey{0, 0, 0, TT(1)};
+
+    set_keymap({layer_key});
+
+    /* Press and release TT. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(0);
+    layer_key.press();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* TODO: QMK currently sends an empty report even if nothing needs to be reported to the host! */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(2);
+    layer_key.release();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(0));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(ActionLayer, LayerTapToggleWithKeypress) {
+    GTEST_SKIP() << "TODO: Tap toggle layer does not activate the expected layer on key press.";
+
+    TestDriver driver;
+    KeymapKey  layer_key = KeymapKey{0, 0, 0, TT(1)};
+
+    /* These keys must have the same position in the matrix, only the layer is different. */
+    KeymapKey regular_key = KeymapKey{0, 1, 0, KC_A};
+    set_keymap({layer_key, regular_key, KeymapKey{1, 1, 0, KC_B}});
+
+    /* Press TT. */
+    /* TODO: QMK currently sends an empty report even if nothing needs to be reported to the host! */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(0);
+    layer_key.press();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_B))).Times(1);
+    regular_key.press();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(1);
+    regular_key.release();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* TODO: QMK currently sends an empty report even if nothing needs to be reported to the host! */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(1);
+    layer_key.release();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(0));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(ActionLayer, LayerTapToggleWithToggleWithKeypress) {
+    GTEST_SKIP() << "TODO: Tap toggle layer does not activate the expected layer on key press.";
+
+    TestDriver driver;
+    KeymapKey  layer_key = KeymapKey{0, 0, 0, TT(1)};
+
+    /* These keys must have the same position in the matrix, only the layer is different. */
+    KeymapKey regular_key = KeymapKey{0, 1, 0, KC_A};
+    set_keymap({layer_key, regular_key, KeymapKey{1, 1, 0, KC_B}});
+
+    /* Tap TT five times . */
+    /* TODO: QMK currently sends an empty report even if nothing needs to be reported to the host! */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(9);
+
+    layer_key.press();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    layer_key.release();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(0));
+
+    layer_key.press();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    layer_key.release();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(0));
+
+    layer_key.press();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    layer_key.release();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(0));
+
+    layer_key.press();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    layer_key.release();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(0));
+
+    layer_key.press();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    layer_key.release();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_B))).Times(1);
+    regular_key.press();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(1);
+    regular_key.release();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    testing::Mock::VerifyAndClearExpectations(&driver);
 }
 
-// TEST_F(ActionLayer, LayerClear) {
-//     layer_clear();
-//     EXPECT_EQ(layer_state, 0);
-// }
-
-// TEST_F(ActionLayer, LayerMove) {
-//     layer_move(0);
-//     EXPECT_EQ(layer_state, 1);
-//     layer_move(3);
-//     EXPECT_EQ(layer_state, 0b1000);
-// }
-
-// TEST_F(ActionLayer, LayerOn) {
-//     layer_clear();
-//     layer_on(1);
-//     layer_on(3);
-//     layer_on(3);
-//     EXPECT_EQ(layer_state, 0b1010);
-// }
-
-// TEST_F(ActionLayer, LayerOff) {
-//     layer_clear();
-//     layer_on(1);
-//     layer_on(3);
-//     layer_off(3);
-//     layer_off(2);
-//     EXPECT_EQ(layer_state, 0b1000);
-// }
+TEST_F(ActionLayer, LayerTapReleasedBeforeKeypressReleaseWithModifiers) {
+    GTEST_SKIP() << "TODO: Modifiers are erroneously discarded on layer changes, although a key that introduced the modifier is still held.";
+    TestDriver driver;
+    InSequence s;
+
+    KeymapKey layer_0_key_0 = KeymapKey{0, 0, 0, LT(1, KC_T)};
+    KeymapKey layer_1_key_1 = KeymapKey{1, 1, 0, RALT(KC_9)};
+
+    set_keymap({layer_0_key_0, layer_1_key_1});
+
+    /* Press layer tap and wait for tapping term to switch to layer 1 */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(0);
+    layer_0_key_0.press();
+    idle_for(TAPPING_TERM);
+    EXPECT_TRUE(layer_state_is(0));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press key with layer 1 mapping, result basically expected
+     * altough more reports are send then necessary. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_RALT))).Times(1);
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_RALT, KC_9))).Times(1);
+    layer_1_key_1.press();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(1));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release layer tap key, no report is send because key is still held. */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    layer_0_key_0.release();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(0));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Unregister keycode and modifier. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_RALT))).Times(1);
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(1);
+    layer_1_key_1.release();
+    run_one_scan_loop();
+    EXPECT_TRUE(layer_state_is(0));
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
diff --git a/tests/basic/test_keypress.cpp b/tests/basic/test_keypress.cpp
index cf839f8c16..70613bbd6d 100644
--- a/tests/basic/test_keypress.cpp
+++ b/tests/basic/test_keypress.cpp
@@ -14,11 +14,11 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include "keycode.h"
 #include "test_common.hpp"
 
 using testing::_;
 using testing::InSequence;
-using testing::Return;
 
 class KeyPress : public TestFixture {};
 
@@ -30,95 +30,156 @@ TEST_F(KeyPress, SendKeyboardIsNotCalledWhenNoKeyIsPressed) {
 
 TEST_F(KeyPress, CorrectKeyIsReportedWhenPressed) {
     TestDriver driver;
-    press_key(0, 0);
-    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_A)));
+    auto       key = KeymapKey(0, 0, 0, KC_A);
+
+    set_keymap({key});
+
+    key.press();
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(key.report_code)));
     keyboard_task();
-    release_key(0, 0);
+
+    key.release();
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
     keyboard_task();
 }
 
+TEST_F(KeyPress, ANonMappedKeyDoesNothing) {
+    TestDriver driver;
+    auto       key = KeymapKey(0, 0, 0, KC_NO);
+
+    set_keymap({key});
+
+    key.press();
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    keyboard_task();
+    keyboard_task();
+}
+
 TEST_F(KeyPress, CorrectKeysAreReportedWhenTwoKeysArePressed) {
     TestDriver driver;
-    press_key(1, 0);
-    press_key(0, 3);
+    auto       key_b = KeymapKey(0, 0, 0, KC_B);
+    auto       key_c = KeymapKey(0, 1, 1, KC_C);
+
+    set_keymap({key_b, key_c});
+
+    key_b.press();
+    key_c.press();
     // Note that QMK only processes one key at a time
     // See issue #1476 for more information
-    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_B)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(key_b.report_code)));
     keyboard_task();
-    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_B, KC_C)));
+
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(key_b.report_code, key_c.report_code)));
     keyboard_task();
-    release_key(1, 0);
-    release_key(0, 3);
+
+    key_b.release();
+    key_c.release();
     // Note that the first key released is the first one in the matrix order
-    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_C)));
-    keyboard_task();
-    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(key_c.report_code)));
     keyboard_task();
-}
 
-TEST_F(KeyPress, ANonMappedKeyDoesNothing) {
-    TestDriver driver;
-    press_key(2, 0);
-    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
-    keyboard_task();
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
     keyboard_task();
 }
 
 TEST_F(KeyPress, LeftShiftIsReportedCorrectly) {
     TestDriver driver;
-    press_key(3, 0);
-    press_key(0, 0);
+    auto       key_a    = KeymapKey(0, 0, 0, KC_A);
+    auto       key_lsft = KeymapKey(0, 3, 0, KC_LEFT_SHIFT);
+
+    set_keymap({key_a, key_lsft});
+
+    key_lsft.press();
+    key_a.press();
+
     // Unfortunately modifiers are also processed in the wrong order
     // See issue #1476 for more information
-    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_A)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(key_a.report_code)));
     keyboard_task();
-    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_A, KC_LEFT_SHIFT)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(key_a.report_code, key_lsft.report_code)));
     keyboard_task();
-    release_key(0, 0);
-    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT)));
+
+    key_a.release();
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(key_lsft.report_code)));
     keyboard_task();
-    release_key(3, 0);
+
+    key_lsft.release();
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
     keyboard_task();
 }
 
 TEST_F(KeyPress, PressLeftShiftAndControl) {
     TestDriver driver;
-    press_key(3, 0);
-    press_key(5, 0);
+    auto       key_lsft  = KeymapKey(0, 3, 0, KC_LEFT_SHIFT);
+    auto       key_lctrl = KeymapKey(0, 5, 0, KC_LEFT_CTRL);
+
+    set_keymap({key_lctrl, key_lsft});
+
+    key_lsft.press();
+    key_lctrl.press();
+
     // Unfortunately modifiers are also processed in the wrong order
     // See issue #1476 for more information
-    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(key_lsft.report_code)));
     keyboard_task();
-    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT, KC_LEFT_CTRL)));
+
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(key_lsft.report_code, key_lctrl.report_code)));
+    keyboard_task();
+
+    key_lsft.release();
+    key_lctrl.release();
+
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(key_lctrl.report_code)));
+    keyboard_task();
+
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
     keyboard_task();
 }
 
 TEST_F(KeyPress, LeftAndRightShiftCanBePressedAtTheSameTime) {
     TestDriver driver;
-    press_key(3, 0);
-    press_key(4, 0);
+    auto       key_lsft = KeymapKey(0, 3, 0, KC_LEFT_SHIFT);
+    auto       key_rsft = KeymapKey(0, 4, 0, KC_RIGHT_SHIFT);
+
+    set_keymap({key_rsft, key_lsft});
+
+    key_lsft.press();
+    key_rsft.press();
     // Unfortunately modifiers are also processed in the wrong order
     // See issue #1476 for more information
-    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(key_lsft.report_code)));
+    keyboard_task();
+
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(key_lsft.report_code, key_rsft.report_code)));
+    keyboard_task();
+
+    key_lsft.release();
+    key_rsft.release();
+
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(key_rsft.report_code)));
     keyboard_task();
-    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT, KC_RIGHT_SHIFT)));
+
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
     keyboard_task();
 }
 
 TEST_F(KeyPress, RightShiftLeftControlAndCharWithTheSameKey) {
     TestDriver driver;
-    press_key(6, 0);
+    auto       combo_key = KeymapKey(0, 0, 0, RSFT(LCTL(KC_O)));
+
+    set_keymap({combo_key});
+
     // BUG: The press is split into two reports
     // BUG: It reports RSFT instead of LSFT
     // See issue #524 for more information
     // The underlying cause is that we use only one bit to represent the right hand
     // modifiers.
+    combo_key.press();
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_RIGHT_SHIFT, KC_RIGHT_CTRL)));
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_RIGHT_SHIFT, KC_RIGHT_CTRL, KC_O)));
     keyboard_task();
-    release_key(6, 0);
+
+    combo_key.release();
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_RIGHT_SHIFT, KC_RIGHT_CTRL)));
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
     keyboard_task();
@@ -127,25 +188,29 @@ TEST_F(KeyPress, RightShiftLeftControlAndCharWithTheSameKey) {
 TEST_F(KeyPress, PressPlusEqualReleaseBeforePress) {
     TestDriver driver;
     InSequence s;
+    auto       key_plus = KeymapKey(0, 1, 1, KC_PLUS);
+    auto       key_eql  = KeymapKey(0, 0, 1, KC_EQL);
+
+    set_keymap({key_plus, key_eql});
 
-    press_key(1, 1);  // KC_PLUS
+    key_plus.press();
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT)));
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT, KC_EQUAL)));
     run_one_scan_loop();
     testing::Mock::VerifyAndClearExpectations(&driver);
 
-    release_key(1, 1);  // KC_PLUS
+    key_plus.release();
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT)));
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
     run_one_scan_loop();
     testing::Mock::VerifyAndClearExpectations(&driver);
 
-    press_key(0, 1);  // KC_EQUAL
-    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_EQUAL)));
+    key_eql.press();
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(key_eql.report_code)));
     run_one_scan_loop();
     testing::Mock::VerifyAndClearExpectations(&driver);
 
-    release_key(0, 1);  // KC_EQUAL
+    key_eql.release();
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
     run_one_scan_loop();
     testing::Mock::VerifyAndClearExpectations(&driver);
@@ -154,27 +219,31 @@ TEST_F(KeyPress, PressPlusEqualReleaseBeforePress) {
 TEST_F(KeyPress, PressPlusEqualDontReleaseBeforePress) {
     TestDriver driver;
     InSequence s;
+    auto       key_plus = KeymapKey(0, 1, 1, KC_PLUS);
+    auto       key_eql  = KeymapKey(0, 0, 1, KC_EQUAL);
+
+    set_keymap({key_plus, key_eql});
 
-    press_key(1, 1);  // KC_PLUS
+    key_plus.press();
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT)));
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT, KC_EQUAL)));
     run_one_scan_loop();
     testing::Mock::VerifyAndClearExpectations(&driver);
 
-    press_key(0, 1);  // KC_EQUAL
+    key_eql.press();
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_EQUAL)));
     run_one_scan_loop();
     testing::Mock::VerifyAndClearExpectations(&driver);
 
-    release_key(1, 1);  // KC_PLUS
+    key_plus.release();
     // BUG: Should really still return KC_EQUAL, but this is fine too
     // It's also called twice for some reason
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(2);
     run_one_scan_loop();
     testing::Mock::VerifyAndClearExpectations(&driver);
 
-    release_key(0, 1);  // KC_EQUAL
+    key_eql.release();
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
     run_one_scan_loop();
     testing::Mock::VerifyAndClearExpectations(&driver);
@@ -183,24 +252,28 @@ TEST_F(KeyPress, PressPlusEqualDontReleaseBeforePress) {
 TEST_F(KeyPress, PressEqualPlusReleaseBeforePress) {
     TestDriver driver;
     InSequence s;
+    auto       key_plus = KeymapKey(0, 1, 1, KC_PLUS);
+    auto       key_eql  = KeymapKey(0, 0, 1, KC_EQUAL);
 
-    press_key(0, 1);  // KC_EQUAL
+    set_keymap({key_plus, key_eql});
+
+    key_eql.press();
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_EQUAL)));
     run_one_scan_loop();
     testing::Mock::VerifyAndClearExpectations(&driver);
 
-    release_key(0, 1);  // KC_EQUAL
+    key_eql.release();
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
     run_one_scan_loop();
     testing::Mock::VerifyAndClearExpectations(&driver);
 
-    press_key(1, 1);  // KC_PLUS
+    key_plus.press();
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT)));
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT, KC_EQUAL)));
     run_one_scan_loop();
     testing::Mock::VerifyAndClearExpectations(&driver);
 
-    release_key(1, 1);  // KC_PLUS
+    key_plus.release();
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT)));
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
     run_one_scan_loop();
@@ -210,13 +283,17 @@ TEST_F(KeyPress, PressEqualPlusReleaseBeforePress) {
 TEST_F(KeyPress, PressEqualPlusDontReleaseBeforePress) {
     TestDriver driver;
     InSequence s;
+    auto       key_plus = KeymapKey(0, 1, 1, KC_PLUS);
+    auto       key_eql  = KeymapKey(0, 0, 1, KC_EQL);
+
+    set_keymap({key_plus, key_eql});
 
-    press_key(0, 1);  // KC_EQUAL
+    key_eql.press();
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_EQUAL)));
     run_one_scan_loop();
     testing::Mock::VerifyAndClearExpectations(&driver);
 
-    press_key(1, 1);  // KC_PLUS
+    key_plus.press();
     // BUG: The sequence is a bit strange, but it works, the end result is that
     // KC_PLUS is sent
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT, KC_EQUAL)));
@@ -225,16 +302,16 @@ TEST_F(KeyPress, PressEqualPlusDontReleaseBeforePress) {
     run_one_scan_loop();
     testing::Mock::VerifyAndClearExpectations(&driver);
 
-    release_key(0, 1);  // KC_EQUAL
+    key_eql.release();
     // I guess it's fine to still report shift here
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT)));
     run_one_scan_loop();
     testing::Mock::VerifyAndClearExpectations(&driver);
 
-    release_key(1, 1);  // KC_PLUS
+    key_plus.release();
     // This report is not needed
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT)));
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
     run_one_scan_loop();
     testing::Mock::VerifyAndClearExpectations(&driver);
-}
+}
\ No newline at end of file
diff --git a/tests/basic/test_macro.cpp b/tests/basic/test_macro.cpp
index 1ac6f473fc..ae2f3b32e3 100644
--- a/tests/basic/test_macro.cpp
+++ b/tests/basic/test_macro.cpp
@@ -24,10 +24,25 @@ class Macro : public TestFixture {};
 
 #define AT_TIME(t) WillOnce(InvokeWithoutArgs([current_time]() { EXPECT_EQ(timer_elapsed32(current_time), t); }))
 
+extern "C" const macro_t *action_get_macro(keyrecord_t *record, uint8_t id, uint8_t opt) {
+    if (record->event.pressed) {
+        switch (id) {
+            case 0:
+                return MACRO(D(LSFT), T(H), U(LSFT), T(E), T(L), T(L), T(O), T(SPACE), W(100), D(LSFT), T(W), U(LSFT), I(10), T(O), T(R), T(L), T(D), D(LSFT), T(1), U(LSFT), END);
+        }
+    }
+    return MACRO_NONE;
+};
+
 TEST_F(Macro, PlayASimpleMacro) {
     TestDriver driver;
     InSequence s;
-    press_key(8, 0);
+    auto       key_macro = KeymapKey(0, 8, 0, M(0));
+
+    set_keymap({key_macro});
+
+    key_macro.press();
+
     uint32_t current_time = timer_read32();
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT))).AT_TIME(0);
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT, KC_H))).AT_TIME(0);
@@ -68,4 +83,6 @@ TEST_F(Macro, PlayASimpleMacro) {
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT))).AT_TIME(210);
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).AT_TIME(220);
     run_one_scan_loop();
+
+    key_macro.release();
 }
diff --git a/tests/basic/test_one_shot_keys.cpp b/tests/basic/test_one_shot_keys.cpp
new file mode 100644
index 0000000000..98178912e4
--- /dev/null
+++ b/tests/basic/test_one_shot_keys.cpp
@@ -0,0 +1,197 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "action_util.h"
+#include "keyboard_report_util.hpp"
+#include "test_common.hpp"
+
+using testing::_;
+using testing::InSequence;
+
+class OneShot : public TestFixture {};
+class OneShotParametrizedTestFixture : public ::testing::WithParamInterface<std::pair<KeymapKey, KeymapKey>>, public OneShot {};
+
+TEST_F(OneShot, OSMWithoutAdditionalKeypressDoesNothing) {
+    TestDriver driver;
+    auto       osm_key = KeymapKey(0, 0, 0, OSM(MOD_LSFT), KC_LSFT);
+
+    set_keymap({osm_key});
+
+    /* Press and release OSM key*/
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    osm_key.press();
+    run_one_scan_loop();
+    osm_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* OSM are added when an actual report is send */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(osm_key.report_code)));
+    send_keyboard_report();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Make unit-test pass */
+    clear_oneshot_mods();
+}
+
+#if defined(ONESHOT_TIMEOUT)
+
+TEST_P(OneShotParametrizedTestFixture, OSMExpiredDoesNothing) {
+    TestDriver driver;
+    KeymapKey  osm_key     = GetParam().first;
+    KeymapKey  regular_key = GetParam().second;
+
+    set_keymap({osm_key, regular_key});
+
+    /* Press and release OSM */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    osm_key.press();
+    run_one_scan_loop();
+    osm_key.release();
+    idle_for(ONESHOT_TIMEOUT);
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(regular_key.report_code))).Times(1);
+    regular_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    regular_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+#endif
+
+TEST_P(OneShotParametrizedTestFixture, OSMWithAdditionalKeypress) {
+    TestDriver driver;
+    KeymapKey  osm_key     = GetParam().first;
+    KeymapKey  regular_key = GetParam().second;
+
+    set_keymap({osm_key, regular_key});
+
+    /* Press and release OSM */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    osm_key.press();
+    run_one_scan_loop();
+    osm_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(osm_key.report_code, regular_key.report_code))).Times(1);
+    regular_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    regular_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_P(OneShotParametrizedTestFixture, OSMAsRegularModifierWithAdditionalKeypress) {
+    TestDriver          driver;
+    testing::InSequence s;
+
+    KeymapKey osm_key     = GetParam().first;
+    KeymapKey regular_key = GetParam().second;
+
+    set_keymap({osm_key, regular_key});
+
+    /* Press OSM */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    osm_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release OSM */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(regular_key.report_code, osm_key.report_code))).Times(1);
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(1);
+    osm_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+// clang-format off
+
+INSTANTIATE_TEST_CASE_P(
+    OneShotModifierTests,
+    OneShotParametrizedTestFixture,
+    ::testing::Values(
+        /* first is osm key, second is regular key. */
+        std::make_pair(KeymapKey{0, 0, 0, OSM(MOD_LSFT), KC_LSFT}, KeymapKey{0, 1, 1, KC_A}),
+        std::make_pair(KeymapKey{0, 0, 0, OSM(MOD_LCTL), KC_LCTL}, KeymapKey{0, 1, 1, KC_A}),
+        std::make_pair(KeymapKey{0, 0, 0, OSM(MOD_LALT), KC_LALT}, KeymapKey{0, 1, 1, KC_A}),
+        std::make_pair(KeymapKey{0, 0, 0, OSM(MOD_LGUI), KC_LGUI}, KeymapKey{0, 1, 1, KC_A}),
+        std::make_pair(KeymapKey{0, 0, 0, OSM(MOD_RCTL), KC_RCTL}, KeymapKey{0, 1, 1, KC_A}),
+        std::make_pair(KeymapKey{0, 0, 0, OSM(MOD_RSFT), KC_RSFT}, KeymapKey{0, 1, 1, KC_A}),
+        std::make_pair(KeymapKey{0, 0, 0, OSM(MOD_RALT), KC_RALT}, KeymapKey{0, 1, 1, KC_A}),
+        std::make_pair(KeymapKey{0, 0, 0, OSM(MOD_RGUI), KC_RGUI}, KeymapKey{0, 1, 1, KC_A})
+        ));
+// clang-format on
+
+TEST_F(OneShot, OSLWithAdditionalKeypress) {
+    TestDriver driver;
+    InSequence s;
+    KeymapKey  osl_key     = KeymapKey{0, 0, 0, OSL(1)};
+    KeymapKey  regular_key = KeymapKey{1, 1, 0, KC_A};
+
+    set_keymap({osl_key, regular_key});
+
+    /* Press OSL key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    osl_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release OSL key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(2);
+    osl_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(regular_key.report_code))).Times(2);
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    regular_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    regular_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
diff --git a/tests/basic/test_tapping.cpp b/tests/basic/test_tapping.cpp
index 88ab97eb6e..181b7ca89e 100644
--- a/tests/basic/test_tapping.cpp
+++ b/tests/basic/test_tapping.cpp
@@ -14,8 +14,11 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include "keyboard_report_util.hpp"
+#include "keycode.h"
 #include "test_common.hpp"
 #include "action_tapping.h"
+#include "test_keymap_key.hpp"
 
 using testing::_;
 using testing::InSequence;
@@ -25,14 +28,19 @@ class Tapping : public TestFixture {};
 TEST_F(Tapping, TapA_SHFT_T_KeyReportsKey) {
     TestDriver driver;
     InSequence s;
+    auto       key_shift_hold_p_tap = KeymapKey(0, 7, 0, SFT_T(KC_P));
+
+    set_keymap({key_shift_hold_p_tap});
 
-    press_key(7, 0);
     // Tapping keys does nothing on press
+    key_shift_hold_p_tap.press();
     EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
     run_one_scan_loop();
-    release_key(7, 0);
+
     // First we get the key press
+    key_shift_hold_p_tap.release();
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+
     // Then the release
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
     run_one_scan_loop();
@@ -41,25 +49,38 @@ TEST_F(Tapping, TapA_SHFT_T_KeyReportsKey) {
 TEST_F(Tapping, HoldA_SHFT_T_KeyReportsShift) {
     TestDriver driver;
     InSequence s;
+    auto       mod_tap_hold_key = KeymapKey(0, 7, 0, SFT_T(KC_P));
+
+    set_keymap({mod_tap_hold_key});
+
+    mod_tap_hold_key.press();
 
-    press_key(7, 0);
     // Tapping keys does nothing on press
     EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
     idle_for(TAPPING_TERM);
+
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT)));
     run_one_scan_loop();
+
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
 }
 
 TEST_F(Tapping, ANewTapWithinTappingTermIsBuggy) {
     // See issue #1478 for more information
     TestDriver driver;
     InSequence s;
+    auto       key_shift_hold_p_tap = KeymapKey(0, 7, 0, SFT_T(KC_P));
+
+    set_keymap({key_shift_hold_p_tap});
 
-    press_key(7, 0);
     // Tapping keys does nothing on press
+    key_shift_hold_p_tap.press();
     EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
     run_one_scan_loop();
-    release_key(7, 0);
+    key_shift_hold_p_tap.release();
+
     // First we get the key press
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
     // Then the release
@@ -67,19 +88,20 @@ TEST_F(Tapping, ANewTapWithinTappingTermIsBuggy) {
     run_one_scan_loop();
 
     // This sends KC_P, even if it should do nothing
-    press_key(7, 0);
+    key_shift_hold_p_tap.press();
     // This test should not succed if everything works correctly
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
     run_one_scan_loop();
-    release_key(7, 0);
+
+    key_shift_hold_p_tap.release();
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
     idle_for(TAPPING_TERM + 1);
 
     // On the other hand, nothing is sent if we are outside the tapping term
-    press_key(7, 0);
+    key_shift_hold_p_tap.press();
     EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
     run_one_scan_loop();
-    release_key(7, 0);
+    key_shift_hold_p_tap.release();
 
     // First we get the key press
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
@@ -90,8 +112,12 @@ TEST_F(Tapping, ANewTapWithinTappingTermIsBuggy) {
     // Now we are geting into strange territory, as the hold registers too early here
     // But the stranges part is:
     // If TAPPING_TERM + 1 above is changed to TAPPING_TERM or TAPPING_TERM + 2 it doesn't
-    press_key(7, 0);
+    key_shift_hold_p_tap.press();
     // Shouldn't be called here really
     EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LEFT_SHIFT))).Times(1);
     idle_for(TAPPING_TERM);
-}
+
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    key_shift_hold_p_tap.release();
+    run_one_scan_loop();
+}
\ No newline at end of file
diff --git a/tests/tap_hold_configurations/default_mod_tap/config.h b/tests/tap_hold_configurations/default_mod_tap/config.h
new file mode 100644
index 0000000000..5955b8600a
--- /dev/null
+++ b/tests/tap_hold_configurations/default_mod_tap/config.h
@@ -0,0 +1,21 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "test_common.h"
+
+#define IGNORE_MOD_TAP_INTERRUPT
\ No newline at end of file
diff --git a/tests/tap_hold_configurations/default_mod_tap/test.mk b/tests/tap_hold_configurations/default_mod_tap/test.mk
new file mode 100644
index 0000000000..cfab996e0e
--- /dev/null
+++ b/tests/tap_hold_configurations/default_mod_tap/test.mk
@@ -0,0 +1,18 @@
+# Copyright 2021 Stefan Kerkmann
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# --------------------------------------------------------------------------------
+# Keep this file, even if it is empty, as a marker that this folder contains tests
+# --------------------------------------------------------------------------------
\ No newline at end of file
diff --git a/tests/tap_hold_configurations/default_mod_tap/test_tap_hold.cpp b/tests/tap_hold_configurations/default_mod_tap/test_tap_hold.cpp
new file mode 100644
index 0000000000..90befcdffd
--- /dev/null
+++ b/tests/tap_hold_configurations/default_mod_tap/test_tap_hold.cpp
@@ -0,0 +1,230 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "keyboard_report_util.hpp"
+#include "keycode.h"
+#include "test_common.hpp"
+#include "action_tapping.h"
+#include "test_fixture.hpp"
+#include "test_keymap_key.hpp"
+
+using testing::_;
+using testing::InSequence;
+
+class DefaultTapHold : public TestFixture {};
+
+TEST_F(DefaultTapHold, tap_regular_key_while_mod_tap_key_is_held) {
+    TestDriver driver;
+    InSequence s;
+    auto       mod_tap_hold_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+    auto       regular_key      = KeymapKey(0, 2, 0, KC_A);
+
+    set_keymap({mod_tap_hold_key, regular_key});
+
+    /* Press mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press regular key. */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release regular key. */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P, KC_A)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Idle for tapping term of mod tap hold key. */
+    idle_for(TAPPING_TERM - 3);
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(DefaultTapHold, tap_mod_tap_key_while_mod_tap_key_is_held) {
+    TestDriver driver;
+    InSequence s;
+    auto       first_mod_tap_hold_key  = KeymapKey(0, 1, 0, SFT_T(KC_P));
+    auto       second_mod_tap_hold_key = KeymapKey(0, 2, 0, RSFT_T(KC_A));
+
+    set_keymap({first_mod_tap_hold_key, second_mod_tap_hold_key});
+
+    /* Press first mod-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    first_mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press second tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    second_mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release second tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    second_mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release first mod-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P, KC_A)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    first_mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(DefaultTapHold, tap_regular_key_while_layer_tap_key_is_held) {
+    TestDriver driver;
+    InSequence s;
+    auto       layer_tap_hold_key = KeymapKey(0, 1, 0, LT(1, KC_P));
+    auto       regular_key        = KeymapKey(0, 2, 0, KC_A);
+    auto       layer_key          = KeymapKey(1, 2, 0, KC_B);
+
+    set_keymap({layer_tap_hold_key, regular_key, layer_key});
+
+    /* Press layer-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    layer_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release layer-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_A, KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(_));
+    layer_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(DefaultTapHold, tap_mod_tap_hold_key_two_times) {
+    GTEST_SKIP() << "TODO:Holding a modtap key results in out of bounds access to the keymap, this is a bug in QMK.";
+
+    TestDriver driver;
+    InSequence s;
+    auto       mod_tap_hold_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+
+    set_keymap({mod_tap_hold_key});
+
+    /* Press mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press mod-tap-hold key again. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    mod_tap_hold_key.press();
+    idle_for(TAPPING_TERM);
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(DefaultTapHold, tap_mod_tap_hold_key_twice_and_hold_on_second_time) {
+    GTEST_SKIP() << "TODO:Holding a modtap key results in out of bounds access to the keymap, this is a bug in QMK.";
+
+    TestDriver driver;
+    InSequence s;
+    auto       mod_tap_hold_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+
+    set_keymap({mod_tap_hold_key});
+
+    /* Press mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press mod-tap-hold key again. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    mod_tap_hold_key.press();
+    idle_for(TAPPING_TERM);
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(DefaultTapHold, tap_and_hold_mod_tap_hold_key) {
+    TestDriver driver;
+    InSequence s;
+    auto       mod_tap_hold_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+
+    set_keymap({mod_tap_hold_key});
+
+    /* Press mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSHIFT)));
+    mod_tap_hold_key.press();
+    idle_for(TAPPING_TERM + 1);
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
\ No newline at end of file
diff --git a/tests/tap_hold_configurations/ignore_mod_tap_interrupt/config.h b/tests/tap_hold_configurations/ignore_mod_tap_interrupt/config.h
new file mode 100644
index 0000000000..5955b8600a
--- /dev/null
+++ b/tests/tap_hold_configurations/ignore_mod_tap_interrupt/config.h
@@ -0,0 +1,21 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "test_common.h"
+
+#define IGNORE_MOD_TAP_INTERRUPT
\ No newline at end of file
diff --git a/tests/tap_hold_configurations/ignore_mod_tap_interrupt/test.mk b/tests/tap_hold_configurations/ignore_mod_tap_interrupt/test.mk
new file mode 100644
index 0000000000..efecca2c22
--- /dev/null
+++ b/tests/tap_hold_configurations/ignore_mod_tap_interrupt/test.mk
@@ -0,0 +1,18 @@
+# Copyright 2021 Stefan Kerkmann
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# --------------------------------------------------------------------------------
+# Keep this file, even if it is empty, as a marker that this folder contains tests
+# --------------------------------------------------------------------------------
diff --git a/tests/tap_hold_configurations/ignore_mod_tap_interrupt/test_tap_hold.cpp b/tests/tap_hold_configurations/ignore_mod_tap_interrupt/test_tap_hold.cpp
new file mode 100644
index 0000000000..1702d604d3
--- /dev/null
+++ b/tests/tap_hold_configurations/ignore_mod_tap_interrupt/test_tap_hold.cpp
@@ -0,0 +1,136 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "keyboard_report_util.hpp"
+#include "keycode.h"
+#include "test_common.hpp"
+#include "action_tapping.h"
+#include "test_fixture.hpp"
+#include "test_keymap_key.hpp"
+
+using testing::_;
+using testing::InSequence;
+
+class IgnoreModTapInterrupt : public TestFixture {};
+
+TEST_F(IgnoreModTapInterrupt, tap_regular_key_while_mod_tap_key_is_held) {
+    TestDriver driver;
+    InSequence s;
+    auto       mod_tap_hold_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+    auto       regular_key      = KeymapKey(0, 2, 0, KC_A);
+
+    set_keymap({mod_tap_hold_key, regular_key});
+
+    /* Press mod-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_A, KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(IgnoreModTapInterrupt, tap_mod_tap_key_while_mod_tap_key_is_held) {
+    TestDriver driver;
+    InSequence s;
+    auto       first_mod_tap_hold_key  = KeymapKey(0, 1, 0, SFT_T(KC_P));
+    auto       second_mod_tap_hold_key = KeymapKey(0, 2, 0, RSFT_T(KC_A));
+
+    set_keymap({first_mod_tap_hold_key, second_mod_tap_hold_key});
+
+    /* Press first mod-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    first_mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press second tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    second_mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release second tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    second_mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release first mod-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_A, KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    first_mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(IgnoreModTapInterrupt, tap_regular_key_while_layer_tap_key_is_held) {
+    TestDriver driver;
+    InSequence s;
+    auto       layer_tap_hold_key = KeymapKey(0, 1, 0, LT(1, KC_P));
+    auto       regular_key        = KeymapKey(0, 2, 0, KC_A);
+    auto       layer_key          = KeymapKey(1, 2, 0, KC_B);
+
+    set_keymap({layer_tap_hold_key, regular_key, layer_key});
+
+    /* Press layer-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    layer_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release layer-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P, regular_key.report_code)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    layer_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
diff --git a/tests/tap_hold_configurations/permissive_hold/config.h b/tests/tap_hold_configurations/permissive_hold/config.h
new file mode 100644
index 0000000000..2d5a9849e7
--- /dev/null
+++ b/tests/tap_hold_configurations/permissive_hold/config.h
@@ -0,0 +1,21 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "test_common.h"
+
+#define PERMISSIVE_HOLD
\ No newline at end of file
diff --git a/tests/tap_hold_configurations/permissive_hold/test.mk b/tests/tap_hold_configurations/permissive_hold/test.mk
new file mode 100644
index 0000000000..efecca2c22
--- /dev/null
+++ b/tests/tap_hold_configurations/permissive_hold/test.mk
@@ -0,0 +1,18 @@
+# Copyright 2021 Stefan Kerkmann
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# --------------------------------------------------------------------------------
+# Keep this file, even if it is empty, as a marker that this folder contains tests
+# --------------------------------------------------------------------------------
diff --git a/tests/tap_hold_configurations/permissive_hold/test_one_shot_keys.cpp b/tests/tap_hold_configurations/permissive_hold/test_one_shot_keys.cpp
new file mode 100644
index 0000000000..aa71ec397f
--- /dev/null
+++ b/tests/tap_hold_configurations/permissive_hold/test_one_shot_keys.cpp
@@ -0,0 +1,76 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "action_util.h"
+#include "keyboard_report_util.hpp"
+#include "test_common.hpp"
+
+using testing::_;
+using testing::InSequence;
+
+class OneShot : public TestFixture {};
+class OneShotParametrizedTestFixture : public ::testing::WithParamInterface<std::pair<KeymapKey, KeymapKey>>, public OneShot {};
+
+TEST_P(OneShotParametrizedTestFixture, OSMAsRegularModifierWithAdditionalKeypress) {
+    TestDriver driver;
+    KeymapKey  osm_key     = GetParam().first;
+    KeymapKey  regular_key = GetParam().second;
+
+    set_keymap({osm_key, regular_key});
+
+    /* Press OSM */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    osm_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(osm_key.report_code))).Times(2);
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(regular_key.report_code, osm_key.report_code))).Times(1);
+    regular_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release OSM */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(1);
+    osm_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+// clang-format off
+
+INSTANTIATE_TEST_CASE_P(
+    OneShotModifierTests,
+    OneShotParametrizedTestFixture,
+    ::testing::Values(
+        /* first is osm key, second is regular key. */
+        std::make_pair(KeymapKey{0, 0, 0, OSM(MOD_LSFT), KC_LSFT}, KeymapKey{0, 1, 1, KC_A}),
+        std::make_pair(KeymapKey{0, 0, 0, OSM(MOD_LCTL), KC_LCTL}, KeymapKey{0, 1, 1, KC_A}),
+        std::make_pair(KeymapKey{0, 0, 0, OSM(MOD_LALT), KC_LALT}, KeymapKey{0, 1, 1, KC_A}),
+        std::make_pair(KeymapKey{0, 0, 0, OSM(MOD_LGUI), KC_LGUI}, KeymapKey{0, 1, 1, KC_A}),
+        std::make_pair(KeymapKey{0, 0, 0, OSM(MOD_RCTL), KC_RCTL}, KeymapKey{0, 1, 1, KC_A}),
+        std::make_pair(KeymapKey{0, 0, 0, OSM(MOD_RSFT), KC_RSFT}, KeymapKey{0, 1, 1, KC_A}),
+        std::make_pair(KeymapKey{0, 0, 0, OSM(MOD_RALT), KC_RALT}, KeymapKey{0, 1, 1, KC_A}),
+        std::make_pair(KeymapKey{0, 0, 0, OSM(MOD_RGUI), KC_RGUI}, KeymapKey{0, 1, 1, KC_A})
+        ));
+// clang-format on
\ No newline at end of file
diff --git a/tests/tap_hold_configurations/permissive_hold/test_tap_hold.cpp b/tests/tap_hold_configurations/permissive_hold/test_tap_hold.cpp
new file mode 100644
index 0000000000..ab9dd1518b
--- /dev/null
+++ b/tests/tap_hold_configurations/permissive_hold/test_tap_hold.cpp
@@ -0,0 +1,132 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "keyboard_report_util.hpp"
+#include "keycode.h"
+#include "test_common.hpp"
+#include "action_tapping.h"
+#include "test_fixture.hpp"
+#include "test_keymap_key.hpp"
+
+using testing::_;
+using testing::InSequence;
+class PermissiveHold : public TestFixture {};
+
+TEST_F(PermissiveHold, tap_regular_key_while_mod_tap_key_is_held) {
+    TestDriver driver;
+    InSequence s;
+    auto       mod_tap_hold_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+    auto       regular_key      = KeymapKey(0, 2, 0, KC_A);
+
+    set_keymap({mod_tap_hold_key, regular_key});
+
+    /* Press mod-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSHIFT)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSHIFT, regular_key.report_code)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSHIFT)));
+    regular_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(PermissiveHold, tap_mod_tap_key_while_mod_tap_key_is_held) {
+    TestDriver driver;
+    InSequence s;
+    auto       first_mod_tap_hold_key  = KeymapKey(0, 1, 0, SFT_T(KC_P));
+    auto       second_mod_tap_hold_key = KeymapKey(0, 2, 0, RSFT_T(KC_A));
+
+    set_keymap({first_mod_tap_hold_key, second_mod_tap_hold_key});
+
+    /* Press first mod-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    first_mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press second mod-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    second_mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release second mod-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSHIFT)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSHIFT, second_mod_tap_hold_key.report_code)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSHIFT)));
+    second_mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release first mod-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    first_mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(PermissiveHold, tap_regular_key_while_layer_tap_key_is_held) {
+    TestDriver driver;
+    InSequence s;
+    auto       layer_tap_hold_key = KeymapKey(0, 1, 0, LT(1, KC_P));
+    auto       regular_key        = KeymapKey(0, 2, 0, KC_A);
+    auto       layer_key          = KeymapKey(1, 2, 0, KC_B);
+
+    set_keymap({layer_tap_hold_key, regular_key, layer_key});
+
+    /* Press layer-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    layer_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(layer_key.report_code)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    regular_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release layer-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    layer_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
\ No newline at end of file
diff --git a/tests/tap_hold_configurations/permissive_hold_ignore_mod_tap_interrupt/config.h b/tests/tap_hold_configurations/permissive_hold_ignore_mod_tap_interrupt/config.h
new file mode 100644
index 0000000000..a6abd50bbe
--- /dev/null
+++ b/tests/tap_hold_configurations/permissive_hold_ignore_mod_tap_interrupt/config.h
@@ -0,0 +1,22 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "test_common.h"
+
+#define IGNORE_MOD_TAP_INTERRUPT
+#define PERMISSIVE_HOLD
\ No newline at end of file
diff --git a/tests/tap_hold_configurations/permissive_hold_ignore_mod_tap_interrupt/test.mk b/tests/tap_hold_configurations/permissive_hold_ignore_mod_tap_interrupt/test.mk
new file mode 100644
index 0000000000..efecca2c22
--- /dev/null
+++ b/tests/tap_hold_configurations/permissive_hold_ignore_mod_tap_interrupt/test.mk
@@ -0,0 +1,18 @@
+# Copyright 2021 Stefan Kerkmann
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# --------------------------------------------------------------------------------
+# Keep this file, even if it is empty, as a marker that this folder contains tests
+# --------------------------------------------------------------------------------
diff --git a/tests/tap_hold_configurations/permissive_hold_ignore_mod_tap_interrupt/test_tap_hold.cpp b/tests/tap_hold_configurations/permissive_hold_ignore_mod_tap_interrupt/test_tap_hold.cpp
new file mode 100644
index 0000000000..67f394653f
--- /dev/null
+++ b/tests/tap_hold_configurations/permissive_hold_ignore_mod_tap_interrupt/test_tap_hold.cpp
@@ -0,0 +1,134 @@
+
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "keyboard_report_util.hpp"
+#include "keycode.h"
+#include "test_common.hpp"
+#include "action_tapping.h"
+#include "test_fixture.hpp"
+#include "test_keymap_key.hpp"
+
+using testing::_;
+using testing::InSequence;
+
+class PermissiveHold_IgnoreModTapInterrupt : public TestFixture {};
+
+TEST_F(PermissiveHold_IgnoreModTapInterrupt, tap_regular_key_while_mod_tap_key_is_held) {
+    TestDriver driver;
+    InSequence s;
+    auto       mod_tap_hold_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+    auto       regular_key      = KeymapKey(0, 2, 0, KC_A);
+
+    set_keymap({mod_tap_hold_key, regular_key});
+
+    /* Press mod-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSFT)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSFT, KC_A)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSFT)));
+    regular_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(PermissiveHold_IgnoreModTapInterrupt, tap_mod_tap_key_while_mod_tap_key_is_held) {
+    TestDriver driver;
+    InSequence s;
+    auto       first_mod_tap_hold_key  = KeymapKey(0, 1, 0, SFT_T(KC_P));
+    auto       second_mod_tap_hold_key = KeymapKey(0, 2, 0, RSFT_T(KC_A));
+
+    set_keymap({first_mod_tap_hold_key, second_mod_tap_hold_key});
+
+    /* Press first mod-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    first_mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press second tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    second_mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release second tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSFT)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSFT, KC_A)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSFT)));
+    second_mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release first mod-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    first_mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(PermissiveHold_IgnoreModTapInterrupt, tap_regular_key_while_layer_tap_key_is_held) {
+    TestDriver driver;
+    InSequence s;
+    auto       layer_tap_hold_key = KeymapKey(0, 1, 0, LT(1, KC_P));
+    auto       regular_key        = KeymapKey(0, 2, 0, KC_A);
+    auto       layer_key          = KeymapKey(1, 2, 0, KC_B);
+
+    set_keymap({layer_tap_hold_key, regular_key, layer_key});
+
+    /* Press layer-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    layer_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_B)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    regular_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release layer-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    layer_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
\ No newline at end of file
diff --git a/tests/tap_hold_configurations/retro_tapping/config.h b/tests/tap_hold_configurations/retro_tapping/config.h
new file mode 100644
index 0000000000..4b38f2644b
--- /dev/null
+++ b/tests/tap_hold_configurations/retro_tapping/config.h
@@ -0,0 +1,21 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "test_common.h"
+
+#define RETRO_TAPPING
\ No newline at end of file
diff --git a/tests/tap_hold_configurations/retro_tapping/test.mk b/tests/tap_hold_configurations/retro_tapping/test.mk
new file mode 100644
index 0000000000..efecca2c22
--- /dev/null
+++ b/tests/tap_hold_configurations/retro_tapping/test.mk
@@ -0,0 +1,18 @@
+# Copyright 2021 Stefan Kerkmann
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# --------------------------------------------------------------------------------
+# Keep this file, even if it is empty, as a marker that this folder contains tests
+# --------------------------------------------------------------------------------
diff --git a/tests/tap_hold_configurations/retro_tapping/test_tap_hold.cpp b/tests/tap_hold_configurations/retro_tapping/test_tap_hold.cpp
new file mode 100644
index 0000000000..59ae77f781
--- /dev/null
+++ b/tests/tap_hold_configurations/retro_tapping/test_tap_hold.cpp
@@ -0,0 +1,52 @@
+
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "keyboard_report_util.hpp"
+#include "keycode.h"
+#include "test_common.hpp"
+#include "action_tapping.h"
+#include "test_fixture.hpp"
+#include "test_keymap_key.hpp"
+
+using testing::_;
+using testing::InSequence;
+
+class RetroTapping : public TestFixture {};
+
+TEST_F(RetroTapping, tap_and_hold_mod_tap_hold_key) {
+    TestDriver driver;
+    InSequence s;
+    auto       mod_tap_hold_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+
+    set_keymap({mod_tap_hold_key});
+
+    /* Press mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    mod_tap_hold_key.press();
+    idle_for(TAPPING_TERM);
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod-tap-hold key. */
+    /* TODO: Why is LSHIFT send at all? */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSHIFT)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
\ No newline at end of file
diff --git a/tests/tap_hold_configurations/retro_tapping/test_tapping.cpp b/tests/tap_hold_configurations/retro_tapping/test_tapping.cpp
new file mode 100644
index 0000000000..cf23df8317
--- /dev/null
+++ b/tests/tap_hold_configurations/retro_tapping/test_tapping.cpp
@@ -0,0 +1,112 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "keyboard_report_util.hpp"
+#include "keycode.h"
+#include "test_common.hpp"
+#include "action_tapping.h"
+#include "test_keymap_key.hpp"
+
+using testing::_;
+using testing::InSequence;
+
+class Tapping : public TestFixture {};
+
+TEST_F(Tapping, HoldA_SHFT_T_KeyReportsShift) {
+    TestDriver driver;
+    InSequence s;
+    auto       mod_tap_hold_key = KeymapKey(0, 7, 0, SFT_T(KC_P));
+
+    set_keymap({mod_tap_hold_key});
+
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    mod_tap_hold_key.press();
+    idle_for(TAPPING_TERM);
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSFT)));
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(Tapping, ANewTapWithinTappingTermIsBuggy) {
+    TestDriver driver;
+    InSequence s;
+    auto       key_shift_hold_p_tap = KeymapKey(0, 7, 0, SFT_T(KC_P));
+
+    set_keymap({key_shift_hold_p_tap});
+
+    /* Press mod_tap_hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    key_shift_hold_p_tap.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod_tap_hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    key_shift_hold_p_tap.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press mod_tap_hold key again */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    key_shift_hold_p_tap.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod_tap_hold key again */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    key_shift_hold_p_tap.release();
+    idle_for(TAPPING_TERM + 1);
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press mod_tap_hold key again */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    key_shift_hold_p_tap.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod_tap_hold key again */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    key_shift_hold_p_tap.release();
+    idle_for(TAPPING_TERM + 1);
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press mod_tap_hold key again */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    key_shift_hold_p_tap.press();
+    idle_for(TAPPING_TERM);
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod_tap_hold key again */
+    /* TODO: Why is KC_LSFT send? */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSFT)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    key_shift_hold_p_tap.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
\ No newline at end of file
diff --git a/tests/tap_hold_configurations/tapping_force_hold/config.h b/tests/tap_hold_configurations/tapping_force_hold/config.h
new file mode 100644
index 0000000000..3b4646338a
--- /dev/null
+++ b/tests/tap_hold_configurations/tapping_force_hold/config.h
@@ -0,0 +1,21 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "test_common.h"
+
+#define TAPPING_FORCE_HOLD
\ No newline at end of file
diff --git a/tests/tap_hold_configurations/tapping_force_hold/test.mk b/tests/tap_hold_configurations/tapping_force_hold/test.mk
new file mode 100644
index 0000000000..efecca2c22
--- /dev/null
+++ b/tests/tap_hold_configurations/tapping_force_hold/test.mk
@@ -0,0 +1,18 @@
+# Copyright 2021 Stefan Kerkmann
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# --------------------------------------------------------------------------------
+# Keep this file, even if it is empty, as a marker that this folder contains tests
+# --------------------------------------------------------------------------------
diff --git a/tests/tap_hold_configurations/tapping_force_hold/test_action_layer.cpp b/tests/tap_hold_configurations/tapping_force_hold/test_action_layer.cpp
new file mode 100644
index 0000000000..02416eed73
--- /dev/null
+++ b/tests/tap_hold_configurations/tapping_force_hold/test_action_layer.cpp
@@ -0,0 +1,81 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "keyboard_report_util.hpp"
+#include "test_common.hpp"
+
+using testing::_;
+using testing::InSequence;
+
+class ActionLayer : public TestFixture {};
+
+TEST_F(ActionLayer, LayerTapToggleWithToggleWithKeypress) {
+    TestDriver driver;
+    KeymapKey  layer_key = KeymapKey{0, 0, 0, TT(1)};
+
+    /* These keys must have the same position in the matrix, only the layer is different. */
+    KeymapKey regular_key = KeymapKey{0, 1, 0, KC_A};
+    set_keymap({layer_key, regular_key, KeymapKey{1, 1, 0, KC_B}});
+
+    /* Tap TT five times . */
+    /* TODO: QMK currently sends an empty report even if nothing needs to be reported to the host! */
+    /* TODO: Tapping Force Hold breaks TT */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(10);
+
+    layer_key.press();
+    run_one_scan_loop();
+    layer_key.release();
+    run_one_scan_loop();
+    expect_layer_state(0);
+
+    layer_key.press();
+    run_one_scan_loop();
+    layer_key.release();
+    run_one_scan_loop();
+    expect_layer_state(0);
+
+    layer_key.press();
+    run_one_scan_loop();
+    layer_key.release();
+    run_one_scan_loop();
+    expect_layer_state(0);
+
+    layer_key.press();
+    run_one_scan_loop();
+    layer_key.release();
+    run_one_scan_loop();
+    expect_layer_state(0);
+
+    layer_key.press();
+    run_one_scan_loop();
+    layer_key.release();
+    run_one_scan_loop();
+    expect_layer_state(0);
+
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_A))).Times(1);
+    regular_key.press();
+    run_one_scan_loop();
+    expect_layer_state(0);
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(1);
+    regular_key.release();
+    run_one_scan_loop();
+    expect_layer_state(0);
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
\ No newline at end of file
diff --git a/tests/tap_hold_configurations/tapping_force_hold/test_tap_hold.cpp b/tests/tap_hold_configurations/tapping_force_hold/test_tap_hold.cpp
new file mode 100644
index 0000000000..cb68429617
--- /dev/null
+++ b/tests/tap_hold_configurations/tapping_force_hold/test_tap_hold.cpp
@@ -0,0 +1,215 @@
+
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "keyboard_report_util.hpp"
+#include "keycode.h"
+#include "test_common.hpp"
+#include "action_tapping.h"
+#include "test_fixture.hpp"
+#include "test_keymap_key.hpp"
+
+using testing::_;
+using testing::InSequence;
+
+class TappingForceHold : public TestFixture {};
+
+TEST_F(TappingForceHold, tap_regular_key_while_mod_tap_key_is_held) {
+    TestDriver driver;
+    InSequence s;
+    auto       mod_tap_hold_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+    auto       regular_key      = KeymapKey(0, 2, 0, KC_A);
+
+    set_keymap({mod_tap_hold_key, regular_key});
+
+    /* Press mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press regular key. */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release regular key. */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSFT)));
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Idle for tapping term of mod tap hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSFT)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSFT, KC_A)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSFT)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    idle_for(TAPPING_TERM - 3);
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(TappingForceHold, tap_mod_tap_key_while_mod_tap_key_is_held) {
+    TestDriver driver;
+    InSequence s;
+    auto       first_mod_tap_hold_key  = KeymapKey(0, 1, 0, SFT_T(KC_P));
+    auto       second_mod_tap_hold_key = KeymapKey(0, 2, 0, RSFT_T(KC_A));
+
+    set_keymap({first_mod_tap_hold_key, second_mod_tap_hold_key});
+
+    /* Press first mod-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    first_mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press second tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    second_mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release second tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    second_mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release first mod-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSFT)));
+    first_mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Idle for tapping term of first mod tap hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSFT)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSFT, KC_A)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSFT)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    idle_for(TAPPING_TERM - 3);
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(TappingForceHold, tap_regular_key_while_layer_tap_key_is_held) {
+    TestDriver driver;
+    InSequence s;
+    auto       layer_tap_hold_key = KeymapKey(0, 1, 0, LT(1, KC_P));
+    auto       regular_key        = KeymapKey(0, 2, 0, KC_A);
+    auto       layer_key          = KeymapKey(1, 2, 0, KC_B);
+
+    set_keymap({layer_tap_hold_key, regular_key, layer_key});
+
+    /* Press layer-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    layer_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release regular key */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    regular_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release layer-tap-hold key */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_A, KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(_));
+    layer_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(TappingForceHold, tap_mod_tap_hold_key_two_times) {
+    TestDriver driver;
+    InSequence s;
+    auto       mod_tap_hold_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+
+    set_keymap({mod_tap_hold_key});
+
+    /* Press mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press mod-tap-hold key again. */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
+
+TEST_F(TappingForceHold, tap_mod_tap_hold_key_twice_and_hold_on_second_time) {
+    TestDriver driver;
+    InSequence s;
+    auto       mod_tap_hold_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+
+    set_keymap({mod_tap_hold_key});
+
+    /* Press mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    mod_tap_hold_key.press();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_P)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Press mod-tap-hold key again. */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    mod_tap_hold_key.press();
+    idle_for(TAPPING_TERM);
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Release mod-tap-hold key. */
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport(KC_LSHIFT)));
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport()));
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    testing::Mock::VerifyAndClearExpectations(&driver);
+}
diff --git a/tests/basic/rules.mk b/tests/test_common/build.mk
index 9fb5d43610..aeb3057854 100644
--- a/tests/basic/rules.mk
+++ b/tests/test_common/build.mk
@@ -1,4 +1,4 @@
-# Copyright 2017 Fred Sundvik
+# Copyright 2021 Stefan Kerkmann
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -13,4 +13,4 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-CUSTOM_MATRIX=yes
+CUSTOM_MATRIX=yes
\ No newline at end of file
diff --git a/tests/test_common/keyboard_report_util.cpp b/tests/test_common/keyboard_report_util.cpp
index f73cf239e0..e148c76beb 100644
--- a/tests/test_common/keyboard_report_util.cpp
+++ b/tests/test_common/keyboard_report_util.cpp
@@ -44,16 +44,21 @@ bool operator==(const report_keyboard_t& lhs, const report_keyboard_t& rhs) {
     return lhs.mods == rhs.mods && lhskeys == rhskeys;
 }
 
-std::ostream& operator<<(std::ostream& stream, const report_keyboard_t& value) {
-    stream << "Keyboard report:" << std::endl;
-    stream << "Mods: " << (uint32_t)value.mods << std::endl;
-    stream << "Keys: ";
+std::ostream& operator<<(std::ostream& stream, const report_keyboard_t& report) {
+    auto keys = get_keys(report);
+
     // TODO: This should probably print friendly names for the keys
-    for (uint32_t k : get_keys(value)) {
-        stream << k << " ";
+    stream << "Keyboard Report: Mods (" << (uint32_t)report.mods << ") Keys (";
+
+    for (auto key = keys.cbegin(); key != keys.cend();) {
+        stream << +(*key);
+        key++;
+        if (key != keys.cend()) {
+            stream << ",";
+        }
     }
-    stream << std::endl;
-    return stream;
+
+    return stream << ")" << std::endl;
 }
 
 KeyboardReportMatcher::KeyboardReportMatcher(const std::vector<uint8_t>& keys) {
diff --git a/tests/test_common/keymap.c b/tests/test_common/keymap.c
new file mode 100644
index 0000000000..fc3a56a007
--- /dev/null
+++ b/tests/test_common/keymap.c
@@ -0,0 +1,33 @@
+/* Copyright 2017 Fred Sundvik
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "quantum.h"
+
+// clang-format off
+
+const uint16_t PROGMEM
+               keymaps[][MATRIX_ROWS][MATRIX_COLS] =
+        {
+            [0] =
+                {
+                   {KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO},
+                   {KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO},
+                   {KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO},
+                   {KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO, KC_NO},
+                },
+};
+
+// clang-format on
diff --git a/tests/test_common/test_common.h b/tests/test_common/test_common.h
new file mode 100644
index 0000000000..19ffcddcea
--- /dev/null
+++ b/tests/test_common/test_common.h
@@ -0,0 +1,4 @@
+#pragma once
+
+#define MATRIX_ROWS 4
+#define MATRIX_COLS 10
\ No newline at end of file
diff --git a/tests/test_common/test_driver.cpp b/tests/test_common/test_driver.cpp
index 84e249d838..2fa2b6a2e7 100644
--- a/tests/test_common/test_driver.cpp
+++ b/tests/test_common/test_driver.cpp
@@ -27,7 +27,10 @@ TestDriver::~TestDriver() { m_this = nullptr; }
 
 uint8_t TestDriver::keyboard_leds(void) { return m_this->m_leds; }
 
-void TestDriver::send_keyboard(report_keyboard_t* report) { m_this->send_keyboard_mock(*report); }
+void TestDriver::send_keyboard(report_keyboard_t* report) {
+    test_logger.trace() << *report;
+    m_this->send_keyboard_mock(*report);
+}
 
 void TestDriver::send_mouse(report_mouse_t* report) { m_this->send_mouse_mock(*report); }
 
diff --git a/tests/test_common/test_driver.hpp b/tests/test_common/test_driver.hpp
index f86308df95..f9197b3634 100644
--- a/tests/test_common/test_driver.hpp
+++ b/tests/test_common/test_driver.hpp
@@ -20,25 +20,26 @@
 #include <stdint.h>
 #include "host.h"
 #include "keyboard_report_util.hpp"
-
+#include "test_logger.hpp"
 
 class TestDriver {
-public:
+   public:
     TestDriver();
     ~TestDriver();
     void set_leds(uint8_t leds) { m_leds = leds; }
 
-    MOCK_METHOD1(send_keyboard_mock, void (report_keyboard_t&));
-    MOCK_METHOD1(send_mouse_mock, void (report_mouse_t&));
-    MOCK_METHOD1(send_system_mock, void (uint16_t));
-    MOCK_METHOD1(send_consumer_mock, void (uint16_t));
-private:
-    static uint8_t keyboard_leds(void);
-    static void send_keyboard(report_keyboard_t *report);
-    static void send_mouse(report_mouse_t* report);
-    static void send_system(uint16_t data);
-    static void send_consumer(uint16_t data);
-    host_driver_t m_driver;
-    uint8_t m_leds = 0;
+    MOCK_METHOD1(send_keyboard_mock, void(report_keyboard_t&));
+    MOCK_METHOD1(send_mouse_mock, void(report_mouse_t&));
+    MOCK_METHOD1(send_system_mock, void(uint16_t));
+    MOCK_METHOD1(send_consumer_mock, void(uint16_t));
+
+   private:
+    static uint8_t     keyboard_leds(void);
+    static void        send_keyboard(report_keyboard_t* report);
+    static void        send_mouse(report_mouse_t* report);
+    static void        send_system(uint16_t data);
+    static void        send_consumer(uint16_t data);
+    host_driver_t      m_driver;
+    uint8_t            m_leds = 0;
     static TestDriver* m_this;
 };
diff --git a/tests/test_common/test_fixture.cpp b/tests/test_common/test_fixture.cpp
index e041df7128..0601b17191 100644
--- a/tests/test_common/test_fixture.cpp
+++ b/tests/test_common/test_fixture.cpp
@@ -1,26 +1,48 @@
 #include "test_fixture.hpp"
+#include <algorithm>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include "gmock/gmock-cardinalities.h"
 #include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "keyboard_report_util.hpp"
+#include "keycode.h"
 #include "test_driver.hpp"
+#include "test_logger.hpp"
 #include "test_matrix.h"
-#include "keyboard.h"
-#include "action.h"
-#include "action_tapping.h"
+#include "test_keymap_key.hpp"
 
 extern "C" {
+#include "action.h"
+#include "action_tapping.h"
+#include "action_util.h"
+#include "action_layer.h"
 #include "debug.h"
 #include "eeconfig.h"
-#include "action_layer.h"
+#include "keyboard.h"
+#include "keymap.h"
 
 void set_time(uint32_t t);
 void advance_time(uint32_t ms);
 }
 
 using testing::_;
-using testing::AnyNumber;
-using testing::Between;
-using testing::Return;
+
+/* This is used for dynamic dispatching keymap_key_to_keycode calls to the current active test_fixture. */
+TestFixture* TestFixture::m_this = nullptr;
+
+/* Override weak QMK function to allow the usage of isolated per-test keymaps in unit-tests.
+ * The actual call is dynamicaly dispatched to the current active test fixture, which in turn has it's own keymap. */
+extern "C" uint16_t keymap_key_to_keycode(uint8_t layer, keypos_t position) {
+    uint16_t keycode;
+    TestFixture::m_this->get_keycode(layer, position, &keycode);
+    return keycode;
+}
 
 void TestFixture::SetUpTestCase() {
+    test_logger.info() << "TestFixture setup-up start." << std::endl;
+
     // The following is enough to bootstrap the values set in main
     eeconfig_init_quantum();
     eeconfig_update_debug(debug_config.raw);
@@ -28,23 +50,99 @@ void TestFixture::SetUpTestCase() {
     TestDriver driver;
     EXPECT_CALL(driver, send_keyboard_mock(_));
     keyboard_init();
+
+    test_logger.info() << "TestFixture setup-up end." << std::endl;
 }
 
 void TestFixture::TearDownTestCase() {}
 
-TestFixture::TestFixture() {}
+TestFixture::TestFixture() { m_this = this; }
 
 TestFixture::~TestFixture() {
+    test_logger.info() << "TestFixture clean-up start." << std::endl;
     TestDriver driver;
-    // Run for a while to make sure all keys are completely released
-    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(AnyNumber());
-    layer_clear();
+
+    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(2);
+
+    /* Reset keyboard state. */
     clear_all_keys();
-    idle_for(TAPPING_TERM + 10);
+
+    clear_keyboard();
+
+    clear_oneshot_mods();
+    clear_oneshot_locked_mods();
+    reset_oneshot_layer();
+
+    layer_clear();
+
+#if defined(SWAP_HANDS_ENABLE)
+    clear_oneshot_swaphands();
+#endif
+
+    idle_for(TAPPING_TERM * 10);
+    testing::Mock::VerifyAndClearExpectations(&driver);
+
+    /* Verify that the matrix really is cleared */
+    EXPECT_CALL(driver, send_keyboard_mock(_)).Times(0);
+    idle_for(TAPPING_TERM * 10);
     testing::Mock::VerifyAndClearExpectations(&driver);
-    // Verify that the matrix really is cleared
-    EXPECT_CALL(driver, send_keyboard_mock(KeyboardReport())).Times(0);
-    idle_for(TAPPING_TERM + 10);
+
+    m_this = nullptr;
+
+    test_logger.info() << "TestFixture clean-up end." << std::endl;
+
+    print_test_log();
+}
+
+void TestFixture::add_key(KeymapKey key) {
+    if (this->find_key(key.layer, key.position)) {
+        FAIL() << "Key is already mapped for layer " << +key.layer << " and (column,row) (" << +key.position.col << "," << +key.position.row << ")";
+    }
+
+    this->keymap.push_back(key);
+}
+
+void TestFixture::set_keymap(std::initializer_list<KeymapKey> keys) {
+    this->keymap.clear();
+    for (auto& key : keys) {
+        add_key(key);
+    }
+}
+
+const KeymapKey* TestFixture::find_key(layer_t layer, keypos_t position) const {
+    auto keymap_key_predicate = [&](KeymapKey candidate) { return candidate.layer == layer && candidate.position.col == position.col && candidate.position.row == position.row; };
+
+    auto result = std::find_if(this->keymap.begin(), this->keymap.end(), keymap_key_predicate);
+
+    if (result != std::end(this->keymap)) {
+        return &(*result);
+    }
+    return nullptr;
+}
+
+void TestFixture::get_keycode(const layer_t layer, const keypos_t position, uint16_t* result) const {
+    bool key_is_out_of_bounds = position.col >= MATRIX_COLS && position.row >= MATRIX_ROWS;
+
+    if (key_is_out_of_bounds) {
+        /* See if this is done in hardware as well, because this is 100% out of bounds reads on all QMK keebs out there. */
+        auto msg = [&]() {
+            std::stringstream msg;
+            msg << "Keycode for position (" << +position.col << "," << +position.row << ") requested! This is out of bounds." << std::endl;
+            return msg.str();
+        }();
+
+        *result = KC_NO;
+        test_logger.error() << msg;
+        EXPECT_FALSE(key_is_out_of_bounds) << msg;
+        return;
+    }
+
+    if (auto key = this->find_key(layer, position)) {
+        *result = key->code;
+        return;
+    }
+
+    FAIL() << "No key is mapped for layer " << +layer << " and (column,row) " << +position.col << "," << +position.row << ")";
 }
 
 void TestFixture::run_one_scan_loop() {
@@ -57,3 +155,17 @@ void TestFixture::idle_for(unsigned time) {
         run_one_scan_loop();
     }
 }
+
+void TestFixture::print_test_log() const {
+    const ::testing::TestInfo* const test_info = ::testing::UnitTest::GetInstance()->current_test_info();
+    if (HasFailure()) {
+        std::cerr << test_info->test_case_name() << "." << test_info->name() << " failed!" << std::endl;
+        test_logger.print_log();
+    }
+    test_logger.reset();
+}
+
+void TestFixture::expect_layer_state(layer_t layer_state) const {
+    test_logger.trace() << "Layer state: (" << +layer_state << ") Highest layer bit: (" << +get_highest_layer(layer_state) << ")" << std::endl;
+    EXPECT_TRUE(layer_state_is(layer_state));
+}
diff --git a/tests/test_common/test_fixture.hpp b/tests/test_common/test_fixture.hpp
index 340503665b..73b5d8d3e8 100644
--- a/tests/test_common/test_fixture.hpp
+++ b/tests/test_common/test_fixture.hpp
@@ -16,15 +16,34 @@
 
 #pragma once
 
+#include <cstdint>
+#include <unordered_map>
+#include <optional>
 #include "gtest/gtest.h"
+#include "keyboard.h"
+#include "test_keymap_key.hpp"
 
 class TestFixture : public testing::Test {
-public:
+   public:
+    static TestFixture* m_this;
+
     TestFixture();
     ~TestFixture();
     static void SetUpTestCase();
     static void TearDownTestCase();
 
+    void set_keymap(std::initializer_list<KeymapKey> keycodes);
+    void add_key(const KeymapKey key);
+
+    const KeymapKey* find_key(const layer_t layer_t, const keypos_t position) const;
+    void                     get_keycode(const layer_t layer, const keypos_t position, uint16_t* result) const;
+
     void run_one_scan_loop();
     void idle_for(unsigned ms);
+
+    void expect_layer_state(layer_t layer) const;
+
+   protected:
+    void                   print_test_log() const;
+    std::vector<KeymapKey> keymap;
 };
diff --git a/tests/test_common/test_keymap_key.cpp b/tests/test_common/test_keymap_key.cpp
new file mode 100644
index 0000000000..878ae097bf
--- /dev/null
+++ b/tests/test_common/test_keymap_key.cpp
@@ -0,0 +1,30 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "test_keymap_key.hpp"
+#include "test_logger.hpp"
+#include "gtest/gtest-message.h"
+#include "gtest/gtest.h"
+
+void KeymapKey::press() {
+    test_logger.trace() << "Key pressed:  (" << +this->position.col << "," << +this->position.row << ")" << std::endl;
+    press_key(this->position.col, this->position.row);
+}
+
+void KeymapKey::release() {
+    test_logger.trace() << "Key released: (" << +this->position.col << "," << +this->position.row << ")" << std::endl;
+    release_key(this->position.col, this->position.row);
+}
\ No newline at end of file
diff --git a/tests/test_common/test_keymap_key.hpp b/tests/test_common/test_keymap_key.hpp
new file mode 100644
index 0000000000..7861cb4a32
--- /dev/null
+++ b/tests/test_common/test_keymap_key.hpp
@@ -0,0 +1,46 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+extern "C" {
+#include "keyboard.h"
+#include "test_matrix.h"
+}
+
+#include <cassert>
+
+typedef uint8_t layer_t;
+
+struct KeymapKey {
+    KeymapKey(layer_t layer, uint8_t col, uint8_t row, uint16_t keycode) : layer(layer), position({.col = col, .row = row}), code(keycode), report_code(keycode) { validate(); }
+    KeymapKey(layer_t layer, uint8_t col, uint8_t row, uint16_t keycode, uint16_t report_code) : layer(layer), position({.col = col, .row = row}), code(keycode), report_code(report_code) { validate(); }
+
+    void press();
+    void release();
+
+    const layer_t  layer;
+    const keypos_t position;
+    const uint16_t code;
+    /* Sometimes the keycode does not match the code that is send in the usb report, so we provide it here. */
+    const uint16_t report_code;
+
+   private:
+    void validate() {
+        assert(position.col <= MATRIX_COLS);
+        assert(position.row <= MATRIX_ROWS);
+    }
+};
\ No newline at end of file
diff --git a/tests/test_common/test_logger.cpp b/tests/test_common/test_logger.cpp
new file mode 100644
index 0000000000..959fdde5ec
--- /dev/null
+++ b/tests/test_common/test_logger.cpp
@@ -0,0 +1,39 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <iostream>
+#include "test_logger.hpp"
+
+TestLogger test_logger;
+
+TestLogger& TestLogger::info() {
+    *this << "[ INFO     ] ";
+    return *this;
+}
+
+TestLogger& TestLogger::trace() {
+    *this << "[ TRACE    ] ";
+    return *this;
+}
+
+TestLogger& TestLogger::error() {
+    *this << "[ ERROR    ] ";
+    return *this;
+}
+
+void TestLogger::reset() { this->m_log.str(""); };
+
+void TestLogger::print_log() { std::cerr << this->m_log.str(); }
diff --git a/tests/test_common/test_logger.hpp b/tests/test_common/test_logger.hpp
new file mode 100644
index 0000000000..348af7fab8
--- /dev/null
+++ b/tests/test_common/test_logger.hpp
@@ -0,0 +1,35 @@
+/* Copyright 2021 Stefan Kerkmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <ostream>
+#include <sstream>
+
+class TestLogger : public std::ostream {
+   public:
+    TestLogger() : std::ostream(&m_log){};
+    TestLogger& info();
+    TestLogger& trace();
+    TestLogger& error();
+    void print_log();
+    void reset();
+
+   private:
+    std::stringbuf m_log;
+};
+
+extern TestLogger test_logger;
\ No newline at end of file