Fix Mod-Tap combo regression (#20669)

* Add keyevent for combo keyrecord

* Fix formatting

* Update quantum/process_keycode/process_combo.c

Co-authored-by: Sergey Vlasov <sigprof@gmail.com>

* Add combo unit-tests and hot-fix process_record_tap_hint

...as this function tries to lookup the combo keys passed in. This will
be refactored in a later pr.

---------

Co-authored-by: Sergey Vlasov <sigprof@gmail.com>
Co-authored-by: Stefan Kerkmann <karlk90@pm.me>

3 files changed, 84 insertions, 0 deletions

diff --git a/tests/combo/config.h b/tests/combo/config.h
new file mode 100644
index 0000000000..8052932634
--- /dev/null
+++ b/tests/combo/config.h
@@ -0,0 +1,8 @@
+// Copyright 2023 Stefan Kerkmann (@KarlK90)
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "test_common.h"
+
+#define TAPPING_TERM 200
diff --git a/tests/combo/test.mk b/tests/combo/test.mk
new file mode 100644
index 0000000000..ce6f9fc2b0
--- /dev/null
+++ b/tests/combo/test.mk
@@ -0,0 +1,4 @@
+# Copyright 2023 Stefan Kerkmann (@KarlK90)
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+COMBO_ENABLE = yes
diff --git a/tests/combo/test_combo.cpp b/tests/combo/test_combo.cpp
new file mode 100644
index 0000000000..b7aea27f4c
--- /dev/null
+++ b/tests/combo/test_combo.cpp
@@ -0,0 +1,72 @@
+// Copyright 2023 Stefan Kerkmann (@KarlK90)
+// Copyright 2023 @filterpaper
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "keyboard_report_util.hpp"
+#include "quantum.h"
+#include "keycode.h"
+#include "test_common.h"
+#include "test_driver.hpp"
+#include "test_fixture.hpp"
+#include "test_keymap_key.hpp"
+
+extern "C" {
+enum combos { modtest, osmshift, COMBO_LENGTH };
+uint16_t COMBO_LEN = COMBO_LENGTH;
+
+uint16_t const modtest_combo[]  = {KC_Y, KC_U, COMBO_END};
+uint16_t const osmshift_combo[] = {KC_Z, KC_X, COMBO_END};
+
+// clang-format off
+combo_t key_combos[] = {
+    [modtest]  = COMBO(modtest_combo, RSFT_T(KC_SPACE)),
+    [osmshift] = COMBO(osmshift_combo, OSM(MOD_LSFT))
+};
+// clang-format on
+}
+
+using testing::_;
+using testing::InSequence;
+
+class Combo : public TestFixture {};
+
+TEST_F(Combo, combo_modtest_tapped) {
+    TestDriver driver;
+    KeymapKey  key_y(0, 0, 1, KC_Y);
+    KeymapKey  key_u(0, 0, 2, KC_U);
+    set_keymap({key_y, key_u});
+
+    EXPECT_REPORT(driver, (KC_SPACE));
+    EXPECT_EMPTY_REPORT(driver);
+    tap_combo({key_y, key_u});
+    VERIFY_AND_CLEAR(driver);
+}
+
+TEST_F(Combo, combo_modtest_held_longer_than_tapping_term) {
+    TestDriver driver;
+    KeymapKey  key_y(0, 0, 1, KC_Y);
+    KeymapKey  key_u(0, 0, 2, KC_U);
+    set_keymap({key_y, key_u});
+
+    EXPECT_REPORT(driver, (KC_RIGHT_SHIFT));
+    EXPECT_EMPTY_REPORT(driver);
+    tap_combo({key_y, key_u}, TAPPING_TERM + 1);
+    VERIFY_AND_CLEAR(driver);
+}
+
+TEST_F(Combo, combo_osmshift_tapped) {
+    TestDriver driver;
+    KeymapKey  key_z(0, 0, 1, KC_Z);
+    KeymapKey  key_x(0, 0, 2, KC_X);
+    KeymapKey  key_i(0, 0, 3, KC_I);
+    set_keymap({key_z, key_x, key_i});
+
+    EXPECT_NO_REPORT(driver);
+    tap_combo({key_z, key_x});
+    VERIFY_AND_CLEAR(driver);
+
+    EXPECT_REPORT(driver, (KC_I, KC_LEFT_SHIFT));
+    EXPECT_EMPTY_REPORT(driver);
+    tap_key(key_i);
+    VERIFY_AND_CLEAR(driver);
+}