1 files changed, 96 insertions, 0 deletions
diff --git a/pw_sync/recursive_mutex_facade_test.cc b/pw_sync/recursive_mutex_facade_test.cc
new file mode 100644
index 000000000..6dd2bfbc8
--- /dev/null
+++ b/pw_sync/recursive_mutex_facade_test.cc
@@ -0,0 +1,96 @@
+// Copyright 2022 The Pigweed Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
+// use this file except in compliance with the License. You may obtain a copy of
+// the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations under
+// the License.
+
+#include <chrono>
+
+#include "gtest/gtest.h"
+#include "pw_sync/recursive_mutex.h"
+
+namespace pw::sync {
+namespace {
+
+extern "C" {
+
+// Functions defined in recusive_mutex_facade_test_c.c that call the API from C.
+void pw_sync_RecursiveMutex_CallLock(pw_sync_RecursiveMutex* mutex);
+bool pw_sync_RecursiveMutex_CallTryLock(pw_sync_RecursiveMutex* mutex);
+void pw_sync_RecursiveMutex_CallUnlock(pw_sync_RecursiveMutex* mutex);
+
+}  // extern "C"
+
+// TODO(b/235284163): Add real concurrency tests once we have pw::thread.
+
+TEST(RecursiveMutex, LockUnlock) PW_NO_LOCK_SAFETY_ANALYSIS {
+  pw::sync::RecursiveMutex mutex;
+  for (int i = 0; i < 10; ++i) {
+    mutex.lock();
+  }
+
+  for (int i = 0; i < 10; ++i) {
+    mutex.unlock();
+  }
+}
+
+RecursiveMutex static_mutex;
+TEST(RecursiveMutex, LockUnlockStatic) PW_NO_LOCK_SAFETY_ANALYSIS {
+  static_mutex.lock();
+  for (int i = 0; i < 10; ++i) {
+    EXPECT_TRUE(static_mutex.try_lock());
+  }
+  for (int i = 0; i < 10; ++i) {
+    static_mutex.unlock();  // undo the try_lock() calls
+  }
+  static_mutex.unlock();  // undo the inital lock() call
+}
+
+TEST(RecursiveMutex, TryLockUnlock) PW_NO_LOCK_SAFETY_ANALYSIS {
+  pw::sync::RecursiveMutex mutex;
+  ASSERT_TRUE(mutex.try_lock());
+
+  const bool locked_again = mutex.try_lock();
+  EXPECT_TRUE(locked_again);
+  if (locked_again) {
+    mutex.unlock();
+  }
+
+  mutex.unlock();
+}
+
+TEST(RecursiveMutex, LockUnlockInC) {
+  pw::sync::RecursiveMutex mutex;
+
+  pw_sync_RecursiveMutex_CallLock(&mutex);
+  pw_sync_RecursiveMutex_CallLock(&mutex);
+  pw_sync_RecursiveMutex_CallLock(&mutex);
+
+  pw_sync_RecursiveMutex_CallUnlock(&mutex);
+  pw_sync_RecursiveMutex_CallUnlock(&mutex);
+  pw_sync_RecursiveMutex_CallUnlock(&mutex);
+}
+
+TEST(RecursiveMutex, TryLockUnlockInC) {
+  pw::sync::RecursiveMutex mutex;
+  ASSERT_TRUE(pw_sync_RecursiveMutex_CallTryLock(&mutex));
+
+  const bool locked_again = pw_sync_RecursiveMutex_CallTryLock(&mutex);
+  EXPECT_TRUE(locked_again);
+  if (locked_again) {
+    pw_sync_RecursiveMutex_CallUnlock(&mutex);
+  }
+
+  pw_sync_RecursiveMutex_CallUnlock(&mutex);
+}
+
+}  // namespace
+}  // namespace pw::sync