Move test into test/std subdirectory.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@224658 91177308-0d34-0410-b5e6-96231b3b80d8

test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.obs/mutex.pass.cpp

@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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
+
+// <shared_mutex>
+
+// template <class Mutex> class shared_lock;
+
+// mutex_type *mutex() const noexcept;
+
+#include <shared_mutex>
+#include <cassert>
+
+#if _LIBCPP_STD_VER > 11
+
+std::shared_timed_mutex m;
+
+#endif  // _LIBCPP_STD_VER > 11
+
+int main()
+{
+#if _LIBCPP_STD_VER > 11
+    std::shared_lock<std::shared_timed_mutex> lk0;
+    assert(lk0.mutex() == nullptr);
+    std::shared_lock<std::shared_timed_mutex> lk1(m);
+    assert(lk1.mutex() == &m);
+    lk1.unlock();
+    assert(lk1.mutex() == &m);
+    static_assert(noexcept(lk0.mutex()), "mutex() must be noexcept");
+#endif  // _LIBCPP_STD_VER > 11
+}