Fix module logic, updated tests, add tests (#584)

Tests/TactilityKernel/Source/FileMutexTest.cpp

@@ -0,0 +1,122 @@
+#include "doctest.h"
+#include <tactility/filesystem/file_mutex.h>
+
+namespace {
+
+int lock_calls = 0;
+int unlock_calls = 0;
+int try_lock_calls = 0;
+bool try_lock_result = true;
+uint32_t try_lock_timeout_seen = 0;
+
+void mock_lock() { lock_calls++; }
+void mock_unlock() { unlock_calls++; }
+bool mock_try_lock(uint32_t timeout) {
+    try_lock_calls++;
+    try_lock_timeout_seen = timeout;
+    return try_lock_result;
+}
+
+int lock_a_calls = 0;
+int lock_b_calls = 0;
+void mock_lock_a() { lock_a_calls++; }
+void mock_lock_b() { lock_b_calls++; }
+
+void reset_mocks() {
+    lock_calls = 0;
+    unlock_calls = 0;
+    try_lock_calls = 0;
+    try_lock_result = true;
+    try_lock_timeout_seen = 0;
+    lock_a_calls = 0;
+    lock_b_calls = 0;
+}
+
+} // namespace
+
+TEST_CASE("file_mutex_get with zero registrations returns a no-op mutex") {
+    FileMutex mutex;
+    file_mutex_get(&mutex, "/nowhere/file.txt");
+
+    CHECK_EQ(mutex.lock, nullptr);
+    CHECK_EQ(mutex.try_lock, nullptr);
+    CHECK_EQ(mutex.unlock, nullptr);
+
+    // Calling through a no-op mutex must be safe, and try_lock must report success.
+    file_mutex_lock(&mutex);
+    CHECK_EQ(file_mutex_try_lock(&mutex, 123), true);
+    file_mutex_unlock(&mutex);
+}
+
+TEST_CASE("file_mutex_register/get with a single registration") {
+    reset_mocks();
+    FileMutex registered = { .lock = mock_lock, .try_lock = mock_try_lock, .unlock = mock_unlock };
+    file_mutex_register(&registered, "/mock1");
+
+    FileMutex mutex;
+
+    // Exact mount path match.
+    file_mutex_get(&mutex, "/mock1");
+    CHECK_EQ(mutex.lock, mock_lock);
+    CHECK_EQ(mutex.try_lock, mock_try_lock);
+    CHECK_EQ(mutex.unlock, mock_unlock);
+
+    // Descendant path match.
+    file_mutex_get(&mutex, "/mock1/nested/file.txt");
+    CHECK_EQ(mutex.lock, mock_lock);
+
+    // Unrelated path falls back to no-op.
+    FileMutex unrelated;
+    file_mutex_get(&unrelated, "/other/file.txt");
+    CHECK_EQ(unrelated.lock, nullptr);
+
+    // Prefix-but-not-descendant path (e.g. "/mock1x") must not match "/mock1".
+    FileMutex prefix_only;
+    file_mutex_get(&prefix_only, "/mock1x/file.txt");
+    CHECK_EQ(prefix_only.lock, nullptr);
+
+    // Exercise the resolved callbacks.
+    file_mutex_get(&mutex, "/mock1");
+    file_mutex_lock(&mutex);
+    CHECK_EQ(lock_calls, 1);
+    CHECK_EQ(file_mutex_try_lock(&mutex, 42), true);
+    CHECK_EQ(try_lock_calls, 1);
+    CHECK_EQ(try_lock_timeout_seen, 42);
+    file_mutex_unlock(&mutex);
+    CHECK_EQ(unlock_calls, 1);
+
+    // Re-registering the same path is a no-op: original callbacks remain in place.
+    FileMutex replacement = { .lock = nullptr, .try_lock = nullptr, .unlock = nullptr };
+    file_mutex_register(&replacement, "/mock1");
+    file_mutex_get(&mutex, "/mock1");
+    CHECK_EQ(mutex.lock, mock_lock);
+}
+
+TEST_CASE("file_mutex_register/get with two registrations resolves to the matching path") {
+    reset_mocks();
+
+    FileMutex mutex_a = { .lock = mock_lock_a, .try_lock = nullptr, .unlock = nullptr };
+    FileMutex mutex_b = { .lock = mock_lock_b, .try_lock = nullptr, .unlock = nullptr };
+
+    file_mutex_register(&mutex_a, "/mock2a");
+    file_mutex_register(&mutex_b, "/mock2b");
+
+    FileMutex resolved;
+
+    file_mutex_get(&resolved, "/mock2a/file.txt");
+    CHECK_EQ(resolved.lock, mock_lock_a);
+
+    file_mutex_get(&resolved, "/mock2b/file.txt");
+    CHECK_EQ(resolved.lock, mock_lock_b);
+
+    // Path matching neither registration falls back to no-op.
+    file_mutex_get(&resolved, "/mock2c/file.txt");
+    CHECK_EQ(resolved.lock, nullptr);
+
+    // Registration order matters: the first matching entry wins, not the longest
+    // prefix. A mount nested under an earlier one is shadowed by it.
+    FileMutex mutex_nested = { .lock = nullptr, .try_lock = nullptr, .unlock = nullptr };
+    file_mutex_register(&mutex_nested, "/mock2a/nested");
+    file_mutex_get(&resolved, "/mock2a/nested/file.txt");
+    CHECK_EQ(resolved.lock, mock_lock_a); // still /mock2a, registered first
+}