Add regression test for tapKeySeq code-expansion key drop

tapKeySeq drops a key when a code-expansion command (hexCodeOf / decCodeOf
/ altCodeOf / uCodeOf) appears earlier in the sequence. For example
`tapKeySeq x y hexCodeOf(!) x y` types `x y 2 1 x` instead of `x y 2 1 x y`.

This adds a TapKeySeq test module reproducing the bug on the right half.
It currently fails (the key after the expansion is dropped); the fix
follows in the next commit.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: kareltucek

right/src/test_suite/CMakeLists.txt

@@ -19,4 +19,5 @@ target_sources(${PROJECT_NAME} PRIVATE
     tests/test_sticky.c
     tests/test_playtime.c
     tests/test_transport.c
+    tests/test_tapkeyseq.c
 )

right/src/test_suite/tests/test_tapkeyseq.c

@@ -0,0 +1,51 @@
+#include "tests.h"
+
+// Regression test for a tapKeySeq bug: when a code-expansion command such as
+// hexCodeOf(...) sits in the middle of the sequence, the key that immediately
+// follows the expansion used to be dropped.
+//
+// `tapKeySeq x y hexCodeOf(!) x y` must type
+//     x y 2 1 x y
+// ('!' == U+0021, so hexCodeOf(!) expands to the key sequence `2 1`). The bug
+// dropped the final key of the whole sequence whenever a code-expansion command
+// preceded it, so the tail came out as `... x` instead of `... x y`. Distinct
+// keys (x/y) around the expansion make a dropped key surface as a wrong-char
+// mismatch rather than only a timeout.
+static const test_action_t test_tapkeyseq_hexcode[] = {
+    TEST_SET_MACRO("u",
+        "tapKeySeq x y hexCodeOf(!) x y\n"
+    ),
+    TEST_PRESS______("u"),
+    TEST_DELAY__(20),
+    // x
+    TEST_EXPECT__________("x"),
+    TEST_EXPECT__________(""),
+    // y
+    TEST_EXPECT__________("y"),
+    TEST_EXPECT__________(""),
+    // hexCodeOf(!) -> 2 1
+    TEST_EXPECT__________("2"),
+    TEST_EXPECT__________(""),
+    TEST_EXPECT__________("1"),
+    TEST_EXPECT__________(""),
+    // x
+    TEST_EXPECT__________("x"),
+    TEST_EXPECT__________(""),
+    // y  (the final key of the sequence — the one the bug dropped)
+    TEST_EXPECT__________("y"),
+    TEST_EXPECT__________(""),
+    TEST_RELEASE__U("u"),
+    TEST_DELAY__(20),
+    TEST_EXPECT__________(""),
+    TEST_END()
+};
+
+static const test_t tapkeyseq_tests[] = {
+    { .name = "tapkeyseq_hexcode", .actions = test_tapkeyseq_hexcode },
+};
+
+const test_module_t TestModule_TapKeySeq = {
+    .name = "TapKeySeq",
+    .tests = tapkeyseq_tests,
+    .testCount = sizeof(tapkeyseq_tests) / sizeof(tapkeyseq_tests[0])
+};

right/src/test_suite/tests/tests.c

@@ -18,6 +18,7 @@ const test_module_t * const AllTestModules[] = {
     &TestModule_Sticky,
     &TestModule_Playtime,
     &TestModule_Transport,
+    &TestModule_TapKeySeq,
 };
 
 const uint16_t AllTestModulesCount = sizeof(AllTestModules) / sizeof(AllTestModules[0]);

right/src/test_suite/tests/tests.h

@@ -32,5 +32,6 @@ extern const test_module_t TestModule_ParserBenevolence;
 extern const test_module_t TestModule_Sticky;
 extern const test_module_t TestModule_Playtime;
 extern const test_module_t TestModule_Transport;
+extern const test_module_t TestModule_TapKeySeq;
 
 #endif