diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/mutex.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/mutex.pass.cpp
index 6025b0c3b465bd..a95c2ef0029de1 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/mutex.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.guard/mutex.pass.cpp
@@ -18,27 +18,29 @@
 //     -> lock_guard<_Mutex>;  // C++17
 
 #include <mutex>
-#include <cstdlib>
 #include <cassert>
-
-#include "make_test_thread.h"
 #include "test_macros.h"
 
-std::mutex m;
+struct TestMutex {
+    bool locked = false;
+    TestMutex() = default;
+    ~TestMutex() { assert(!locked); }
 
-void do_try_lock() {
-  assert(m.try_lock() == false);
-}
+    void lock() { assert(!locked); locked = true; }
+    bool try_lock() { if (locked) return false; locked = true; return true; }
+    void unlock() { assert(locked); locked = false; }
+
+    TestMutex(TestMutex const&) = delete;
+    TestMutex& operator=(TestMutex const&) = delete;
+};
 
 int main(int, char**) {
+  TestMutex m;
   {
-    std::lock_guard<std::mutex> lg(m);
-    std::thread t = support::make_test_thread(do_try_lock);
-    t.join();
+    std::lock_guard<TestMutex> lg(m);
+    assert(m.locked);
   }
-
-  m.lock();
-  m.unlock();
+  assert(!m.locked);
 
 #if TEST_STD_VER >= 17
   std::lock_guard lg(m);
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex.pass.cpp
index ece330134f2cda..863948763e2ef7 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex.pass.cpp
@@ -6,7 +6,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-// UNSUPPORTED: no-threads
 // UNSUPPORTED: c++03, c++11
 
 // <shared_mutex>
@@ -79,10 +78,12 @@ void test() {
 }
 
 int main(int, char**) {
+#ifndef TEST_HAS_NO_THREADS
 #if TEST_STD_VER >= 17
   test<std::shared_mutex>();
 #endif
   test<std::shared_timed_mutex>();
+#endif
   test<TrackedMutex>();
 
   // Use shared_lock with a dummy mutex class that tracks whether each
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/lock.pass.cpp
index d36ca1d38f8f13..9097ac74d1272b 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/lock.pass.cpp
@@ -6,7 +6,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-// UNSUPPORTED: no-threads
 // UNSUPPORTED: c++03, c++11
 
 // <shared_mutex>
@@ -99,10 +98,12 @@ void test() {
 }
 
 int main(int, char**) {
+#ifndef TEST_HAS_NO_THREADS
 #if TEST_STD_VER >= 17
   test<std::shared_mutex>();
 #endif
   test<std::shared_timed_mutex>();
+#endif
   test<TrackedMutex>();
 
   // Use shared_lock with a dummy mutex class that tracks whether each
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock.pass.cpp
index b6146680b6e353..ccab79d4db0160 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock.pass.cpp
@@ -6,7 +6,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-// UNSUPPORTED: no-threads
 // UNSUPPORTED: c++03, c++11
 
 // <shared_mutex>
@@ -104,10 +103,12 @@ void test() {
 }
 
 int main(int, char**) {
+#ifndef TEST_HAS_NO_THREADS
 #if TEST_STD_VER >= 17
   test<std::shared_mutex>();
 #endif
   test<std::shared_timed_mutex>();
+#endif
   test<TrackedMutex>();
 
   // Use shared_lock with a dummy mutex class that tracks whether each