Fix layer switching from tap dances by redoing the keymap lookup (#17935)

8 files changed, 874 insertions, 5 deletions

diff --git a/quantum/process_keycode/process_tap_dance.c b/quantum/process_keycode/process_tap_dance.c
index 3270a1b000..6e8e596673 100644
--- a/quantum/process_keycode/process_tap_dance.c
+++ b/quantum/process_keycode/process_tap_dance.c
@@ -115,12 +115,12 @@ static inline void process_tap_dance_action_on_dance_finished(qk_tap_dance_actio
     }
 }
 
-void preprocess_tap_dance(uint16_t keycode, keyrecord_t *record) {
+bool preprocess_tap_dance(uint16_t keycode, keyrecord_t *record) {
     qk_tap_dance_action_t *action;
 
-    if (!record->event.pressed) return;
+    if (!record->event.pressed) return false;
 
-    if (!active_td || keycode == active_td) return;
+    if (!active_td || keycode == active_td) return false;
 
     action                             = &tap_dance_actions[TD_INDEX(active_td)];
     action->state.interrupted          = true;
@@ -130,6 +130,12 @@ void preprocess_tap_dance(uint16_t keycode, keyrecord_t *record) {
     // Tap dance actions can leave some weak mods active (e.g., if the tap dance is mapped to a keycode with
     // modifiers), but these weak mods should not affect the keypress which interrupted the tap dance.
     clear_weak_mods();
+
+    // Signal that a tap dance has been finished due to being interrupted,
+    // therefore the keymap lookup for the currently processed event needs to
+    // be repeated with the current layer state that might have been updated by
+    // the finished tap dance.
+    return true;
 }
 
 bool process_tap_dance(uint16_t keycode, keyrecord_t *record) {
diff --git a/quantum/process_keycode/process_tap_dance.h b/quantum/process_keycode/process_tap_dance.h
index d97900d96b..d6d6c136dc 100644
--- a/quantum/process_keycode/process_tap_dance.h
+++ b/quantum/process_keycode/process_tap_dance.h
@@ -81,7 +81,7 @@ void reset_tap_dance(qk_tap_dance_state_t *state);
 
 /* To be used internally */
 
-void preprocess_tap_dance(uint16_t keycode, keyrecord_t *record);
+bool preprocess_tap_dance(uint16_t keycode, keyrecord_t *record);
 bool process_tap_dance(uint16_t keycode, keyrecord_t *record);
 void tap_dance_task(void);
 
diff --git a/quantum/quantum.c b/quantum/quantum.c
index ff36e14775..5b5364c8f1 100644
--- a/quantum/quantum.c
+++ b/quantum/quantum.c
@@ -251,7 +251,11 @@ bool process_record_quantum(keyrecord_t *record) {
 #endif
 
 #ifdef TAP_DANCE_ENABLE
-    preprocess_tap_dance(keycode, record);
+    if (preprocess_tap_dance(keycode, record)) {
+        // The tap dance might have updated the layer state, therefore the
+        // result of the keycode lookup might change.
+        keycode = get_record_keycode(record, true);
+    }
 #endif
 
     if (!(
diff --git a/tests/tap_dance/tap_dance_layers/config.h b/tests/tap_dance/tap_dance_layers/config.h
new file mode 100644
index 0000000000..32a19a8c68
--- /dev/null
+++ b/tests/tap_dance/tap_dance_layers/config.h
@@ -0,0 +1,6 @@
+// Copyright 2022 Sergey Vlasov (@sigprof)
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "test_common.h"
diff --git a/tests/tap_dance/tap_dance_layers/tap_dance_defs.c b/tests/tap_dance/tap_dance_layers/tap_dance_defs.c
new file mode 100644
index 0000000000..5ec900c041
--- /dev/null
+++ b/tests/tap_dance/tap_dance_layers/tap_dance_defs.c
@@ -0,0 +1,97 @@
+// Copyright 2022 Sergey Vlasov (@sigprof)
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "quantum.h"
+#include "tap_dance_defs.h"
+
+// Implement custom keycodes which are used to check that the layer switching
+// behaves properly.
+bool process_record_user(uint16_t keycode, keyrecord_t *record) {
+    switch (keycode) {
+        case FAST_AB:
+        case SLOW_AB:
+            if (record->event.pressed) {
+                tap_code(KC_A);
+            } else {
+                tap_code(KC_B);
+            }
+            return keycode == SLOW_AB;
+        case FAST_CD:
+        case SLOW_CD:
+            if (record->event.pressed) {
+                tap_code(KC_C);
+            } else {
+                tap_code(KC_D);
+            }
+            return keycode == SLOW_CD;
+    }
+    return true;
+}
+
+// Implement a custom tap dance with the following behavior:
+// - single tap: KC_APP
+// - single hold: MO(1)
+// - double tap/hold: KC_RCTL
+// (The single tap and hold actions are mostly equivalent to LT(1, KC_APP).)
+
+enum lt_app_state {
+    LTA_NONE,
+    LTA_SINGLE_TAP,
+    LTA_SINGLE_HOLD,
+    LTA_DOUBLE_HOLD,
+};
+
+static enum lt_app_state saved_lt_app_state;
+
+static enum lt_app_state get_lt_app_state(qk_tap_dance_state_t *state) {
+    if (state->count == 1) {
+        if (!state->pressed) {
+            return LTA_SINGLE_TAP;
+        } else {
+            return LTA_SINGLE_HOLD;
+        }
+    } else if (state->count == 2) {
+        return LTA_DOUBLE_HOLD;
+    } else {
+        return LTA_NONE;
+    }
+}
+
+static void lt_app_finished(qk_tap_dance_state_t *state, void *user_data) {
+    saved_lt_app_state = get_lt_app_state(state);
+    switch (saved_lt_app_state) {
+        case LTA_NONE:
+            break;
+        case LTA_SINGLE_TAP:
+            register_code(KC_APP);
+            break;
+        case LTA_SINGLE_HOLD:
+            layer_on(1);
+            break;
+        case LTA_DOUBLE_HOLD:
+            register_code(KC_RCTL);
+            break;
+    }
+}
+
+static void lt_app_reset(qk_tap_dance_state_t *state, void *user_data) {
+    switch (saved_lt_app_state) {
+        case LTA_NONE:
+            break;
+        case LTA_SINGLE_TAP:
+            unregister_code(KC_APP);
+            break;
+        case LTA_SINGLE_HOLD:
+            layer_off(1);
+            break;
+        case LTA_DOUBLE_HOLD:
+            unregister_code(KC_RCTL);
+            break;
+    }
+}
+
+qk_tap_dance_action_t tap_dance_actions[] = {
+    [TD_L_MOVE] = ACTION_TAP_DANCE_LAYER_MOVE(KC_APP, 1),
+    [TD_L_TOGG] = ACTION_TAP_DANCE_LAYER_TOGGLE(KC_APP, 1),
+    [TD_LT_APP] = ACTION_TAP_DANCE_FN_ADVANCED(NULL, lt_app_finished, lt_app_reset),
+};
diff --git a/tests/tap_dance/tap_dance_layers/tap_dance_defs.h b/tests/tap_dance/tap_dance_layers/tap_dance_defs.h
new file mode 100644
index 0000000000..37cab0c2cb
--- /dev/null
+++ b/tests/tap_dance/tap_dance_layers/tap_dance_defs.h
@@ -0,0 +1,29 @@
+// Copyright 2022 Sergey Vlasov (@sigprof)
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+enum custom_keycodes {
+    // (FAST|SLOW)_xy = tap KC_x on press, tap KC_y on release.  For FAST_xy
+    // process_record_user() returns false to stop processing early; for
+    // SLOW_xy process_record_user() returns true, therefore all other key
+    // handlers are invoked.
+    FAST_AB = SAFE_RANGE,
+    FAST_CD,
+    SLOW_AB,
+    SLOW_CD,
+};
+
+enum tap_dance_ids {
+    TD_L_MOVE, // ACTION_TAP_DANCE_LAYER_MOVE(KC_APP, 1)
+    TD_L_TOGG, // ACTION_TAP_DANCE_LAYER_TOGGLE(KC_APP, 1)
+    TD_LT_APP, // similar to LT(1, KC_APP) with KC_RCTL on tap+hold or double tap
+};
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/tests/tap_dance/tap_dance_layers/test.mk b/tests/tap_dance/tap_dance_layers/test.mk
new file mode 100644
index 0000000000..b4cdc9b088
--- /dev/null
+++ b/tests/tap_dance/tap_dance_layers/test.mk
@@ -0,0 +1,10 @@
+# Copyright 2022 Sergey Vlasov (@sigprof)
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+# --------------------------------------------------------------------------------
+# Keep this file, even if it is empty, as a marker that this folder contains tests
+# --------------------------------------------------------------------------------
+
+TAP_DANCE_ENABLE = yes
+
+SRC += tap_dance_defs.c
diff --git a/tests/tap_dance/tap_dance_layers/test_tap_dance_layers.cpp b/tests/tap_dance/tap_dance_layers/test_tap_dance_layers.cpp
new file mode 100644
index 0000000000..8b736b19c6
--- /dev/null
+++ b/tests/tap_dance/tap_dance_layers/test_tap_dance_layers.cpp
@@ -0,0 +1,717 @@
+// Copyright 2022 Sergey Vlasov (@sigprof)
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "keyboard_report_util.hpp"
+#include "keycode.h"
+#include "test_common.hpp"
+#include "action_tapping.h"
+#include "test_keymap_key.hpp"
+#include "tap_dance_defs.h"
+
+using testing::_;
+using testing::InSequence;
+
+struct TapDanceKeyParams {
+    std::string name;                  // Tap dance name (part of test name)
+    uint16_t    keycode;               // Tap dance keycode (TD(n))
+    uint16_t    expect_on_tap;         // Keycode for single tap
+    uint16_t    expect_on_hold;        // Keycode for single hold (may be MO(1))
+    uint16_t    expect_on_double_tap;  // Keycode for double tap (may be MO(1))
+    uint16_t    expect_on_double_hold; // Keycode for double hold (may be MO(1))
+};
+
+struct OtherKeyLayerParams {
+    uint16_t keycode;           // Keycode in the keymap
+    uint16_t expect_on_press;   // Keycode to expect on press
+    uint16_t expect_on_release; // Keycode to expect on release (may be KC_NO if none)
+};
+
+struct OtherKeyParams {
+    std::string         name; // Other key name (part of test name)
+    OtherKeyLayerParams l0;   // Keycodes for layer 0
+    OtherKeyLayerParams l1;   // Keycodes for layer 1
+};
+
+typedef std::tuple<TapDanceKeyParams, OtherKeyParams> TapDanceLayersParams;
+
+class TapDanceLayers : public ::testing::WithParamInterface<TapDanceLayersParams>, public TestFixture {
+   protected:
+    TapDanceKeyParams tap_dance;
+    OtherKeyParams    other_key;
+
+    std::unique_ptr<KeymapKey> key_td, key_td_l1, key_other, key_other_l1;
+
+    void SetUp() override {
+        std::tie(tap_dance, other_key) = GetParam();
+
+        key_td       = std::make_unique<KeymapKey>(0, 1, 0, tap_dance.keycode);
+        key_td_l1    = std::make_unique<KeymapKey>(1, 1, 0, KC_TRNS);
+        key_other    = std::make_unique<KeymapKey>(0, 2, 0, other_key.l0.keycode);
+        key_other_l1 = std::make_unique<KeymapKey>(1, 2, 0, other_key.l1.keycode);
+
+        set_keymap({*key_td, *key_td_l1, *key_other, *key_other_l1});
+    }
+};
+
+static const TapDanceKeyParams tap_dance_keys[] = {
+    TapDanceKeyParams{
+        "LayerMove",
+        TD(TD_L_MOVE),
+        KC_APP,
+        KC_APP,
+        MO(1),
+        MO(1),
+    },
+    TapDanceKeyParams{
+        "LayerToggle",
+        TD(TD_L_TOGG),
+        KC_APP,
+        KC_APP,
+        MO(1),
+        MO(1),
+    },
+    TapDanceKeyParams{
+        "CustomLT",
+        TD(TD_LT_APP),
+        KC_APP,
+        MO(1),
+        KC_RCTL,
+        KC_RCTL,
+    },
+};
+
+static const OtherKeyParams other_keys[] = {
+    OtherKeyParams{
+        "Builtin",
+        OtherKeyLayerParams{KC_A, KC_A, KC_NO},
+        OtherKeyLayerParams{KC_B, KC_B, KC_NO},
+    },
+    OtherKeyParams{
+        "CustomFast",
+        OtherKeyLayerParams{FAST_AB, KC_A, KC_B},
+        OtherKeyLayerParams{FAST_CD, KC_C, KC_D},
+    },
+    OtherKeyParams{
+        "CustomSlow",
+        OtherKeyLayerParams{SLOW_AB, KC_A, KC_B},
+        OtherKeyLayerParams{SLOW_CD, KC_C, KC_D},
+    },
+};
+
+// clang-format off
+INSTANTIATE_TEST_CASE_P(
+    Layers,
+    TapDanceLayers,
+    ::testing::Combine(
+        ::testing::ValuesIn(tap_dance_keys),
+        ::testing::ValuesIn(other_keys)
+    ),
+    [](const ::testing::TestParamInfo<TapDanceLayersParams>& info) {
+        return std::get<0>(info.param).name + std::get<1>(info.param).name;
+    }
+);
+// clang-format on
+
+// Test single tap of the tap dance key with tapping term delay after the tap.
+TEST_P(TapDanceLayers, SingleTap) {
+    TestDriver driver;
+    InSequence s;
+
+    // The tap of the tap dance key does not result in sending a report
+    // immediately.
+    EXPECT_NO_REPORT(driver);
+    tap_key(*key_td);
+
+    // After the tapping term expires, a tap event for the single tap keycode
+    // is generated.
+    idle_for(TAPPING_TERM - 1);
+    EXPECT_REPORT(driver, (tap_dance.expect_on_tap));
+    EXPECT_EMPTY_REPORT(driver);
+    run_one_scan_loop();
+
+    // Pressing the other key produces the reports for the layer 0 mapping of
+    // that key.
+    EXPECT_REPORT(driver, (other_key.l0.expect_on_press));
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_EMPTY_REPORT(driver);
+    }
+    key_other->press();
+    run_one_scan_loop();
+
+    // Releasing the other key produces the reports for the layer 0 mapping of
+    // that key.
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_REPORT(driver, (other_key.l0.expect_on_release));
+    }
+    EXPECT_EMPTY_REPORT(driver);
+    key_other->release();
+    run_one_scan_loop();
+}
+
+// Test single tap of the tap dance key without a delay between the tap dance
+// key and the other key.
+TEST_P(TapDanceLayers, SingleTapFast) {
+    TestDriver driver;
+    InSequence s;
+
+    // The tap of the tap dance key does not result in sending a report
+    // immediately.
+    EXPECT_NO_REPORT(driver);
+    tap_key(*key_td);
+
+    // A quick press of the other key causes the tap event for the tap dance to
+    // be sent before the press event for the other key, and the layer 0
+    // mapping is used for the other key.
+    EXPECT_REPORT(driver, (tap_dance.expect_on_tap));
+    EXPECT_EMPTY_REPORT(driver);
+    EXPECT_REPORT(driver, (other_key.l0.expect_on_press));
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_EMPTY_REPORT(driver);
+    }
+    key_other->press();
+    run_one_scan_loop();
+
+    // Releasing the other key produces the reports for the layer 0 mapping of
+    // that key.
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_REPORT(driver, (other_key.l0.expect_on_release));
+    }
+    EXPECT_EMPTY_REPORT(driver);
+    key_other->release();
+    run_one_scan_loop();
+}
+
+// Test single hold of the tap dance key with tapping term delay after the hold
+// (test variant for tap dances which switch the layer on hold).
+TEST_P(TapDanceLayers, SingleHoldLayer) {
+    if (tap_dance.expect_on_hold != MO(1)) {
+        // Do nothing - the SingleHoldKeycode test would run instead.
+        return;
+    }
+
+    TestDriver driver;
+    InSequence s;
+
+    // No report gets sent immediately after the hold of the tap dance key.
+    EXPECT_NO_REPORT(driver);
+    key_td->press();
+    run_one_scan_loop();
+
+    // After the tapping term expires, the tap dance finishes and switches the
+    // layer, but does not send a report.
+    EXPECT_NO_REPORT(driver);
+    idle_for(TAPPING_TERM);
+    run_one_scan_loop();
+
+    // Pressing the other key produces the reports for the layer 1 mapping of
+    // that key.
+    EXPECT_REPORT(driver, (other_key.l1.expect_on_press));
+    if (other_key.l1.expect_on_release != KC_NO) {
+        EXPECT_EMPTY_REPORT(driver);
+    }
+    key_other->press();
+    run_one_scan_loop();
+
+    // Releasing the tap dance key does not produce a report.
+    EXPECT_NO_REPORT(driver);
+    key_td->release();
+    run_one_scan_loop();
+
+    // Releasing the other key produces the report for the layer 1 mapping of
+    // that key.
+    if (other_key.l1.expect_on_release != KC_NO) {
+        EXPECT_REPORT(driver, (other_key.l1.expect_on_release));
+    }
+    EXPECT_EMPTY_REPORT(driver);
+    key_other->release();
+    run_one_scan_loop();
+}
+
+// Test single hold of the tap dance key with tapping term delay after the hold
+// (test variant for tap dances which send a keycode on single hold).
+TEST_P(TapDanceLayers, SingleHoldKeycode) {
+    if (tap_dance.expect_on_hold == MO(1)) {
+        // Do nothing - the SingleHoldLayer test would run instead.
+        return;
+    }
+
+    TestDriver driver;
+    InSequence s;
+
+    // No report gets sent immediately after the hold of the tap dance key.
+    EXPECT_NO_REPORT(driver);
+    key_td->press();
+    run_one_scan_loop();
+
+    // After the tapping term expires, the tap dance sends the report with the
+    // hold keycode.
+    EXPECT_NO_REPORT(driver);
+    idle_for(TAPPING_TERM);
+    EXPECT_REPORT(driver, (tap_dance.expect_on_hold));
+    run_one_scan_loop();
+
+    // Pressing the other key produces the reports for the layer 0 mapping of
+    // that key.
+    EXPECT_REPORT(driver, (tap_dance.expect_on_hold, other_key.l0.expect_on_press));
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_REPORT(driver, (tap_dance.expect_on_hold));
+    }
+    key_other->press();
+    run_one_scan_loop();
+
+    // Releasing the tap dance key sends the release report for the
+    // corresponding hold keycode.
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_EMPTY_REPORT(driver);
+    } else {
+        EXPECT_REPORT(driver, (other_key.l0.expect_on_press));
+    }
+    key_td->release();
+    run_one_scan_loop();
+
+    // Releasing the other key produces the reports for the layer 0 mapping of
+    // that key.
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_REPORT(driver, (other_key.l0.expect_on_release));
+    }
+    EXPECT_EMPTY_REPORT(driver);
+    key_other->release();
+    run_one_scan_loop();
+}
+
+// Test single hold of the tap dance key without tapping term delay after the
+// hold (test variant for tap dances which switch the layer on hold).
+TEST_P(TapDanceLayers, SingleHoldFastLayer) {
+    if (tap_dance.expect_on_hold != MO(1)) {
+        // Do nothing - the SingleHoldFastKeycode test would run instead.
+        return;
+    }
+
+    TestDriver driver;
+    InSequence s;
+
+    // No report gets sent immediately after the hold of the tap dance key.
+    EXPECT_NO_REPORT(driver);
+    key_td->press();
+    run_one_scan_loop();
+
+    // Pressing the other key produces the reports for the layer 1 mapping of
+    // that key.
+    EXPECT_REPORT(driver, (other_key.l1.expect_on_press));
+    if (other_key.l1.expect_on_release != KC_NO) {
+        EXPECT_EMPTY_REPORT(driver);
+    }
+    key_other->press();
+    run_one_scan_loop();
+
+    // Releasing the tap dance key does not produce a report.
+    EXPECT_NO_REPORT(driver);
+    key_td->release();
+    run_one_scan_loop();
+
+    // Releasing the other key produces the reports for the layer 1 mapping of
+    // that key.
+    if (other_key.l1.expect_on_release != KC_NO) {
+        EXPECT_REPORT(driver, (other_key.l1.expect_on_release));
+    }
+    EXPECT_EMPTY_REPORT(driver);
+    key_other->release();
+    run_one_scan_loop();
+}
+
+// Test single hold of the tap dance key without tapping term delay after the hold
+// (test variant for tap dances which send a keycode on single hold).
+TEST_P(TapDanceLayers, SingleHoldFastKeycode) {
+    if (tap_dance.expect_on_hold == MO(1)) {
+        // Do nothing - the SingleHoldFastLayer test would run instead.
+        return;
+    }
+
+    TestDriver driver;
+    InSequence s;
+
+    // No report gets sent immediately after the hold of the tap dance key.
+    EXPECT_NO_REPORT(driver);
+    key_td->press();
+    run_one_scan_loop();
+
+    // Pressing the other key produces first the report for the tap dance hold
+    // keycode, and then the reports for the layer 0 mapping of the other key.
+    EXPECT_REPORT(driver, (tap_dance.expect_on_hold));
+    EXPECT_REPORT(driver, (tap_dance.expect_on_hold, other_key.l0.expect_on_press));
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_REPORT(driver, (tap_dance.expect_on_hold));
+    }
+    key_other->press();
+    run_one_scan_loop();
+
+    // Releasing the tap dance key sends a release report for the corresponding
+    // hold keycode.
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_EMPTY_REPORT(driver);
+    } else {
+        EXPECT_REPORT(driver, (other_key.l0.expect_on_press));
+    }
+    key_td->release();
+    run_one_scan_loop();
+
+    // Releasing the other key produces the report for the layer 0 mapping of
+    // that key.
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_REPORT(driver, (other_key.l0.expect_on_release));
+    }
+    EXPECT_EMPTY_REPORT(driver);
+    key_other->release();
+    run_one_scan_loop();
+}
+
+// Test double tap of the tap dance key with tapping term delay after the hold
+// (test variant for tap dances which switch the layer on double tap).
+TEST_P(TapDanceLayers, DoubleTapLayer) {
+    if (tap_dance.expect_on_double_tap != MO(1)) {
+        // Do nothing - the DoubleTapKeycode test would run instead.
+        return;
+    }
+
+    TestDriver driver;
+    InSequence s;
+
+    // No report gets sent immediately after the double tap of the tap dance
+    // key.
+    EXPECT_NO_REPORT(driver);
+    tap_key(*key_td);
+    tap_key(*key_td);
+
+    // After the tapping term this tap dance does not send a report too.
+    EXPECT_NO_REPORT(driver);
+    idle_for(TAPPING_TERM);
+    run_one_scan_loop();
+
+    // Pressing the other key produces the reports for the layer 1 mapping of
+    // that key.
+    EXPECT_REPORT(driver, (other_key.l1.expect_on_press));
+    if (other_key.l1.expect_on_release != KC_NO) {
+        EXPECT_EMPTY_REPORT(driver);
+    }
+    key_other->press();
+    run_one_scan_loop();
+
+    // Releasing the other key produces the report for the layer 1 mapping of
+    // that key.
+    if (other_key.l1.expect_on_release != KC_NO) {
+        EXPECT_REPORT(driver, (other_key.l1.expect_on_release));
+    }
+    EXPECT_EMPTY_REPORT(driver);
+    key_other->release();
+    run_one_scan_loop();
+}
+
+// Test double tap of the tap dance key with tapping term delay after the hold
+// (test variant for tap dances which send a keycode on double tap).
+TEST_P(TapDanceLayers, DoubleTapKeycode) {
+    if (tap_dance.expect_on_double_tap == MO(1)) {
+        // Do nothing - the DoubleTapLayer test would run instead.
+        return;
+    }
+
+    TestDriver driver;
+    InSequence s;
+
+    // No report gets sent immediately after the double tap of the tap dance
+    // key.
+    EXPECT_NO_REPORT(driver);
+    tap_key(*key_td);
+    tap_key(*key_td);
+
+    // After the tapping term this tap dance sends the double tap keycode.
+    idle_for(TAPPING_TERM - 1);
+    EXPECT_REPORT(driver, (tap_dance.expect_on_double_tap));
+    EXPECT_EMPTY_REPORT(driver);
+    run_one_scan_loop();
+
+    // Pressing the other key produces the reports for the layer 0 mapping of
+    // that key.
+    EXPECT_REPORT(driver, (other_key.l0.expect_on_press));
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_EMPTY_REPORT(driver);
+    }
+    key_other->press();
+    run_one_scan_loop();
+
+    // Releasing the other key produces the report for the layer 0 mapping of
+    // that key.
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_REPORT(driver, (other_key.l0.expect_on_release));
+    }
+    EXPECT_EMPTY_REPORT(driver);
+    key_other->release();
+    run_one_scan_loop();
+}
+
+// Test double tap of the tap dance key without tapping term delay after the
+// hold (test variant for tap dances which switch the layer on double tap).
+TEST_P(TapDanceLayers, DoubleTapFastLayer) {
+    if (tap_dance.expect_on_double_tap != MO(1)) {
+        // Do nothing - the DoubleTapFastKeycode test would run instead.
+        return;
+    }
+
+    TestDriver driver;
+    InSequence s;
+
+    // No report gets sent immediately after the double tap of the tap dance
+    // key.
+    EXPECT_NO_REPORT(driver);
+    tap_key(*key_td);
+    tap_key(*key_td);
+
+    // Pressing the other key produces the reports for the layer 1 mapping of
+    // that key.
+    EXPECT_REPORT(driver, (other_key.l1.expect_on_press));
+    if (other_key.l1.expect_on_release != KC_NO) {
+        EXPECT_EMPTY_REPORT(driver);
+    }
+    key_other->press();
+    run_one_scan_loop();
+
+    // Releasing the other key produces the report for the layer 1 mapping of
+    // that key.
+    if (other_key.l1.expect_on_release != KC_NO) {
+        EXPECT_REPORT(driver, (other_key.l1.expect_on_release));
+    }
+    EXPECT_EMPTY_REPORT(driver);
+    key_other->release();
+    run_one_scan_loop();
+}
+
+// Test double tap of the tap dance key without tapping term delay after the
+// hold (test variant for tap dances which send a keycode on double tap).
+TEST_P(TapDanceLayers, DoubleTapFastKeycode) {
+    if (tap_dance.expect_on_double_tap == MO(1)) {
+        // Do nothing - the DoubleTapFastLayer test would run instead.
+        return;
+    }
+
+    TestDriver driver;
+    InSequence s;
+
+    // No report gets sent immediately after the double tap of the tap dance
+    // key.
+    EXPECT_NO_REPORT(driver);
+    tap_key(*key_td);
+    tap_key(*key_td);
+
+    // Pressing the other key produces first the report for the tap dance
+    // double tap keycode, and then the reports for the layer 0 mapping of the
+    // other key.
+    EXPECT_REPORT(driver, (tap_dance.expect_on_double_tap));
+    EXPECT_EMPTY_REPORT(driver);
+    EXPECT_REPORT(driver, (other_key.l0.expect_on_press));
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_EMPTY_REPORT(driver);
+    }
+    key_other->press();
+    run_one_scan_loop();
+
+    // Releasing the other key produces the report for the layer 0 mapping of
+    // that key.
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_REPORT(driver, (other_key.l0.expect_on_release));
+    }
+    EXPECT_EMPTY_REPORT(driver);
+    key_other->release();
+    run_one_scan_loop();
+}
+
+// Test double hold of the tap dance key with tapping term delay after the hold
+// (test variant for tap dances which switch the layer on double hold).
+TEST_P(TapDanceLayers, DoubleHoldLayer) {
+    if (tap_dance.expect_on_double_hold != MO(1)) {
+        // Do nothing - the DoubleHoldKeycode test would run instead.
+        return;
+    }
+
+    TestDriver driver;
+    InSequence s;
+
+    // No report gets sent immediately after the double hold of the tap dance
+    // key.
+    EXPECT_NO_REPORT(driver);
+    tap_key(*key_td);
+    key_td->press();
+    run_one_scan_loop();
+
+    // After the tapping term expires, the tap dance finishes and switches the
+    // layer, but does not send a report.
+    EXPECT_NO_REPORT(driver);
+    idle_for(TAPPING_TERM);
+    run_one_scan_loop();
+
+    // Pressing the other key produces the reports for the layer 1 mapping of
+    // that key.
+    EXPECT_REPORT(driver, (other_key.l1.expect_on_press));
+    if (other_key.l1.expect_on_release != KC_NO) {
+        EXPECT_EMPTY_REPORT(driver);
+    }
+    key_other->press();
+    run_one_scan_loop();
+
+    // Releasing the tap dance key does not produce a report.
+    EXPECT_NO_REPORT(driver);
+    key_td->release();
+    run_one_scan_loop();
+
+    // Releasing the other key produces the report for the layer 1 mapping of
+    // that key.
+    if (other_key.l1.expect_on_release != KC_NO) {
+        EXPECT_REPORT(driver, (other_key.l1.expect_on_release));
+    }
+    EXPECT_EMPTY_REPORT(driver);
+    key_other->release();
+    run_one_scan_loop();
+}
+
+// Test double hold of the tap dance key with tapping term delay after the hold
+// (test variant for tap dances which send a keycode on double hold).
+TEST_P(TapDanceLayers, DoubleHoldKeycode) {
+    if (tap_dance.expect_on_double_hold == MO(1)) {
+        // Do nothing - the DoubleHoldLayer test would run instead.
+        return;
+    }
+
+    TestDriver driver;
+    InSequence s;
+
+    // No report gets sent immediately after the double hold of the tap dance
+    // key.
+    EXPECT_NO_REPORT(driver);
+    tap_key(*key_td);
+    key_td->press();
+    run_one_scan_loop();
+
+    // After the tapping term expires, the tap dance sends the report with the
+    // double hold keycode.
+    EXPECT_NO_REPORT(driver);
+    idle_for(TAPPING_TERM);
+    EXPECT_REPORT(driver, (tap_dance.expect_on_double_hold));
+    run_one_scan_loop();
+
+    // Pressing the other key produces the reports for the layer 0 mapping of
+    // that key.
+    EXPECT_REPORT(driver, (tap_dance.expect_on_double_hold, other_key.l0.expect_on_press));
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_REPORT(driver, (tap_dance.expect_on_double_hold));
+    }
+    key_other->press();
+    run_one_scan_loop();
+
+    // Releasing the tap dance key sends the release report for the
+    // corresponding double hold keycode.
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_EMPTY_REPORT(driver);
+    } else {
+        EXPECT_REPORT(driver, (other_key.l0.expect_on_press));
+    }
+    key_td->release();
+    run_one_scan_loop();
+
+    // Releasing the other key produces the reports for the layer 0 mapping of
+    // that key.
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_REPORT(driver, (other_key.l0.expect_on_release));
+    }
+    EXPECT_EMPTY_REPORT(driver);
+    key_other->release();
+    run_one_scan_loop();
+}
+
+// Test double hold of the tap dance key without tapping term delay after the
+// hold (test variant for tap dances which switch the layer on double hold).
+TEST_P(TapDanceLayers, DoubleHoldFastLayer) {
+    if (tap_dance.expect_on_double_hold != MO(1)) {
+        // Do nothing - the DoubleHoldFastKeycode test would run instead.
+        return;
+    }
+
+    TestDriver driver;
+    InSequence s;
+
+    // No report gets sent immediately after the double hold of the tap dance
+    // key.
+    EXPECT_NO_REPORT(driver);
+    tap_key(*key_td);
+    key_td->press();
+    run_one_scan_loop();
+
+    // Pressing the other key produces the reports for the layer 1 mapping of
+    // that key.
+    EXPECT_REPORT(driver, (other_key.l1.expect_on_press));
+    if (other_key.l1.expect_on_release != KC_NO) {
+        EXPECT_EMPTY_REPORT(driver);
+    }
+    key_other->press();
+    run_one_scan_loop();
+
+    // Releasing the tap dance key does not produce a report.
+    EXPECT_NO_REPORT(driver);
+    key_td->release();
+    run_one_scan_loop();
+
+    // Releasing the other key produces the reports for the layer 1 mapping of
+    // that key.
+    if (other_key.l1.expect_on_release != KC_NO) {
+        EXPECT_REPORT(driver, (other_key.l1.expect_on_release));
+    }
+    EXPECT_EMPTY_REPORT(driver);
+    key_other->release();
+    run_one_scan_loop();
+}
+
+// Test double hold of the tap dance key without tapping term delay after the hold
+// (test variant for tap dances which send a keycode on double hold).
+TEST_P(TapDanceLayers, DoubleHoldFastKeycode) {
+    if (tap_dance.expect_on_double_hold == MO(1)) {
+        // Do nothing - the DoubleHoldFastLayer test would run instead.
+        return;
+    }
+
+    TestDriver driver;
+    InSequence s;
+
+    // No report gets sent immediately after the double hold of the tap dance
+    // key.
+    EXPECT_NO_REPORT(driver);
+    tap_key(*key_td);
+    key_td->press();
+    run_one_scan_loop();
+
+    // Pressing the other key produces first the report for the tap dance
+    // double hold keycode, and then the reports for the layer 0 mapping of the
+    // other key.
+    EXPECT_REPORT(driver, (tap_dance.expect_on_double_hold));
+    EXPECT_REPORT(driver, (tap_dance.expect_on_double_hold, other_key.l0.expect_on_press));
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_REPORT(driver, (tap_dance.expect_on_double_hold));
+    }
+    key_other->press();
+    run_one_scan_loop();
+
+    // Releasing the tap dance key sends a release report for the corresponding
+    // double hold keycode.
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_EMPTY_REPORT(driver);
+    } else {
+        EXPECT_REPORT(driver, (other_key.l0.expect_on_press));
+    }
+    key_td->release();
+    run_one_scan_loop();
+
+    // Releasing the other key produces the report for the layer 0 mapping of
+    // that key.
+    if (other_key.l0.expect_on_release != KC_NO) {
+        EXPECT_REPORT(driver, (other_key.l0.expect_on_release));
+    }
+    EXPECT_EMPTY_REPORT(driver);
+    key_other->release();
+    run_one_scan_loop();
+}