diff --git a/aos/common/mutex_test.cpp b/aos/common/mutex_test.cpp
index 7a5c2ce..d9327a1 100644
--- a/aos/common/mutex_test.cpp
+++ b/aos/common/mutex_test.cpp
@@ -59,12 +59,13 @@
   }
   EXPECT_TRUE(test_mutex.TryLock());
 }
+
 TEST_F(MutexTest, MutexUnlocker) {
   test_mutex.Lock();
   {
     aos::MutexUnlocker unlocker(&test_mutex);
     // If this fails, then something weird is going on and the next line might
-    // hang.
+    // hang, so fail immediately.
     ASSERT_TRUE(test_mutex.TryLock());
     test_mutex.Unlock();
   }
@@ -122,6 +123,7 @@
 };
 int MutexFairnessWorkerThread::cyclesRun;
 int MutexFairnessWorkerThread::totalCycles;
+
 // Tests the fairness of the implementation. It does this by repeatedly locking
 // and unlocking a mutex in multiple threads and then checking the standard
 // deviation of the number of times each one locks.