1 files changed, 31 insertions, 0 deletions
diff --git a/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.obs/op_bool.pass.cpp b/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.obs/op_bool.pass.cpp
new file mode 100644
index 000000000000..7004ac0092e1
--- /dev/null
+++ b/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.obs/op_bool.pass.cpp
@@ -0,0 +1,31 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// UNSUPPORTED: libcpp-has-no-threads
+
+// <mutex>
+
+// template <class Mutex> class unique_lock;
+
+// explicit operator bool() const;
+
+#include <mutex>
+#include <cassert>
+
+std::mutex m;
+
+int main()
+{
+    std::unique_lock<std::mutex> lk0;
+    assert(static_cast<bool>(lk0) == false);
+    std::unique_lock<std::mutex> lk1(m);
+    assert(static_cast<bool>(lk1) == true);
+    lk1.unlock();
+    assert(static_cast<bool>(lk1) == false);
+}