diff --git a/tests/pthread_test.cpp b/tests/pthread_test.cpp
index 27d992b..78dbd39 100755
--- a/tests/pthread_test.cpp
+++ b/tests/pthread_test.cpp
@@ -1536,6 +1536,9 @@
 
   ASSERT_EQ(0, pthread_mutex_lock(&m.lock));
   ASSERT_EQ(0, pthread_mutex_unlock(&m.lock));
+  ASSERT_EQ(0, pthread_mutex_trylock(&m.lock));
+  ASSERT_EQ(EBUSY, pthread_mutex_trylock(&m.lock));
+  ASSERT_EQ(0, pthread_mutex_unlock(&m.lock));
 }
 
 TEST(pthread, pthread_mutex_lock_ERRORCHECK) {
@@ -1558,6 +1561,8 @@
   ASSERT_EQ(0, pthread_mutex_unlock(&m.lock));
   ASSERT_EQ(0, pthread_mutex_unlock(&m.lock));
   ASSERT_EQ(0, pthread_mutex_trylock(&m.lock));
+  ASSERT_EQ(0, pthread_mutex_trylock(&m.lock));
+  ASSERT_EQ(0, pthread_mutex_unlock(&m.lock));
   ASSERT_EQ(0, pthread_mutex_unlock(&m.lock));
   ASSERT_EQ(EPERM, pthread_mutex_unlock(&m.lock));
 }