Prepping for async

test/thread/test_thread.c

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+/**
+ * Copyright (c) 2026 Dominic Masters
+ *
+ * This software is released under the MIT License.
+ * https://opensource.org/licenses/MIT
+ */
+
+#include "dusktest.h"
+#include "thread/thread.h"
+#include "util/memory.h"
+
+// --- Helpers ---
+
+static void helper_noop(thread_t *thread) {
+  // intentionally empty: one-shot thread that exits immediately
+}
+
+static void helper_loop(thread_t *thread) {
+  while(!threadShouldStop(thread)) {}
+}
+
+static void helper_write_data(thread_t *thread) {
+  int32_t *value = (int32_t *)thread->data;
+  *value = 42;
+}
+
+// --- thread_t tests ---
+
+static void test_threadInit(void **state) {
+  thread_t thread;
+  threadInit(&thread, helper_noop);
+
+  assert_int_equal(thread.state, THREAD_STATE_STOPPED);
+  assert_ptr_equal(thread.callback, helper_noop);
+  assert_null(thread.data);
+}
+
+static void test_thread_start_stop(void **state) {
+  thread_t thread;
+  threadInit(&thread, helper_noop);
+  threadStart(&thread);
+  threadStop(&thread);
+
+  assert_int_equal(thread.state, THREAD_STATE_STOPPED);
+}
+
+static void test_thread_should_stop(void **state) {
+  // threadStop blocks until STOPPED — if threadShouldStop is broken the
+  // looping callback never exits and this test hangs / times out.
+  thread_t thread;
+  threadInit(&thread, helper_loop);
+  threadStart(&thread);
+  threadStop(&thread);
+
+  assert_int_equal(thread.state, THREAD_STATE_STOPPED);
+}
+
+static void test_thread_data(void **state) {
+  int32_t value = 0;
+
+  thread_t thread;
+  threadInit(&thread, helper_write_data);
+  thread.data = &value;
+  threadStart(&thread);
+  threadStop(&thread);
+
+  // After threadStop the callback has definitely run.
+  assert_int_equal(value, 42);
+}
+
+static void test_thread_restart(void **state) {
+  // A thread can be started, stopped, and started again.
+  thread_t thread;
+  threadInit(&thread, helper_noop);
+
+  threadStart(&thread);
+  threadStop(&thread);
+  assert_int_equal(thread.state, THREAD_STATE_STOPPED);
+
+  // Re-initialise so threadId / state are reset, then start again.
+  threadInit(&thread, helper_noop);
+  threadStart(&thread);
+  threadStop(&thread);
+  assert_int_equal(thread.state, THREAD_STATE_STOPPED);
+}
+
+// --- threadmutex_t tests ---
+
+static void test_threadMutex_lock_unlock(void **state) {
+  threadmutex_t mutex;
+  threadMutexInit(&mutex);
+
+  threadMutexLock(&mutex);
+  threadMutexUnlock(&mutex);
+
+  threadMutexDispose(&mutex);
+}
+
+// Shared data for try-lock test. Uses volatile phase to coordinate the two
+// threads without introducing a second mutex.
+typedef struct {
+  threadmutex_t *target;
+  volatile int32_t phase;
+  bool_t resultWhileLocked;
+  bool_t resultAfterUnlock;
+} trylock_data_t;
+
+static void helper_trylock(thread_t *thread) {
+  trylock_data_t *data = (trylock_data_t *)thread->data;
+
+  // Phase 1: main holds the lock — trylock must fail.
+  while(data->phase != 1) {}
+  data->resultWhileLocked = threadMutexTryLock(data->target);
+  data->phase = 2;
+
+  // Phase 3: main released the lock — trylock must succeed.
+  while(data->phase != 3) {}
+  data->resultAfterUnlock = threadMutexTryLock(data->target);
+  if(data->resultAfterUnlock) {
+    threadMutexUnlock(data->target);
+  }
+  data->phase = 4;
+}
+
+static void test_threadMutex_try_lock(void **state) {
+  threadmutex_t mutex;
+  threadMutexInit(&mutex);
+
+  trylock_data_t data = {
+    .target = &mutex,
+    .phase = 0,
+    .resultWhileLocked = false,
+    .resultAfterUnlock = false
+  };
+
+  thread_t thread;
+  threadInit(&thread, helper_trylock);
+  thread.data = &data;
+  threadStart(&thread);
+
+  // Hold the lock, then let the helper try.
+  threadMutexLock(&mutex);
+  data.phase = 1;
+  while(data.phase != 2) {}
+  assert_false(data.resultWhileLocked);
+
+  // Release, then let the helper try again.
+  threadMutexUnlock(&mutex);
+  data.phase = 3;
+  while(data.phase != 4) {}
+  assert_true(data.resultAfterUnlock);
+
+  threadStop(&thread);
+  threadMutexDispose(&mutex);
+}
+
+// Mutual-exclusion test: N threads each increment a shared counter M times
+// under a mutex. The final value must be exactly N*M.
+#define MUTEX_THREADS     4
+#define MUTEX_ITERATIONS  10000
+
+typedef struct {
+  threadmutex_t *mutex;
+  int32_t *counter;
+} counter_data_t;
+
+static counter_data_t counter_thread_data[MUTEX_THREADS];
+static thread_t counter_threads[MUTEX_THREADS];
+
+static void helper_increment(thread_t *thread) {
+  counter_data_t *data = (counter_data_t *)thread->data;
+  for(int32_t i = 0; i < MUTEX_ITERATIONS; i++) {
+    threadMutexLock(data->mutex);
+    (*data->counter)++;
+    threadMutexUnlock(data->mutex);
+  }
+}
+
+static void test_threadMutex_mutual_exclusion(void **state) {
+  threadmutex_t mutex;
+  threadMutexInit(&mutex);
+  int32_t counter = 0;
+
+  for(int32_t i = 0; i < MUTEX_THREADS; i++) {
+    counter_thread_data[i].mutex = &mutex;
+    counter_thread_data[i].counter = &counter;
+    threadInit(&counter_threads[i], helper_increment);
+    counter_threads[i].data = &counter_thread_data[i];
+  }
+
+  for(int32_t i = 0; i < MUTEX_THREADS; i++) {
+    threadStart(&counter_threads[i]);
+  }
+
+  for(int32_t i = 0; i < MUTEX_THREADS; i++) {
+    threadStop(&counter_threads[i]);
+  }
+
+  assert_int_equal(counter, MUTEX_THREADS * MUTEX_ITERATIONS);
+
+  threadMutexDispose(&mutex);
+}
+
+int main(void) {
+  const struct CMUnitTest tests[] = {
+    cmocka_unit_test(test_threadInit),
+    cmocka_unit_test(test_thread_start_stop),
+    cmocka_unit_test(test_thread_should_stop),
+    cmocka_unit_test(test_thread_data),
+    cmocka_unit_test(test_thread_restart),
+    cmocka_unit_test(test_threadMutex_lock_unlock),
+    cmocka_unit_test(test_threadMutex_try_lock),
+    cmocka_unit_test(test_threadMutex_mutual_exclusion),
+  };
+  return cmocka_run_group_tests(tests, NULL, NULL);
+}