diff --git a/libcxx/test/support/filesystem_test_helper.h b/libcxx/test/support/filesystem_test_helper.h
--- a/libcxx/test/support/filesystem_test_helper.h
+++ b/libcxx/test/support/filesystem_test_helper.h
@@ -18,6 +18,7 @@
 #include <string>
 #include <chrono>
 #include <vector>
+#include <random>
 
 #include "make_string.h"
 #include "test_macros.h"
@@ -30,6 +31,27 @@
 # include <sys/un.h>
 #endif
 
+#if !defined(_LIBCPP_HAS_NO_RANDOM_DEVICE)
+namespace random_utils {
+inline char to_hex(int ch) {
+  return ch < 10 ? static_cast<char>('0' + ch)
+                 : static_cast<char>('a' + (ch - 10));
+}
+
+inline char random_hex_char() {
+  static std::mt19937 rd{std::random_device{}()};
+  static std::uniform_int_distribution<int> mrand{0, 15};
+  return to_hex(mrand(rd));
+}
+std::string random_string(int n) {
+  std::string ret;
+  for (int i = 0; i < n; i++)
+    ret.push_back(random_hex_char());
+  return ret;
+}
+} // end namespace random_utils
+#endif
+
 namespace utils {
 #ifdef _WIN32
     inline int mkdir(const char* path, int mode) { (void)mode; return ::_mkdir(path); }
@@ -292,14 +314,16 @@
 
 private:
     // This could potentially introduce a filesystem race if multiple
-    // scoped_test_envs were created concurrently in the same test (hence
-    // sharing the same cwd). However, it is fairly unlikely to happen as
-    // we generally don't use scoped_test_env from multiple threads, so
-    // this is deemed acceptable.
+    // scoped_test_envs were created concurrently in the same test or if
+    // multiple tests with the same file name run concurrently. If a random
+    // device is available, append a short random string.
     static inline fs::path available_cwd_path() {
         fs::path const cwd = utils::getcwd();
         fs::path const tmp = fs::temp_directory_path();
         std::string base = cwd.filename().string();
+#if !defined(_LIBCPP_HAS_NO_RANDOM_DEVICE)
+        base += "-" + random_utils::random_string(4);
+#endif
         int i = 0;
         fs::path p = tmp / (base + "-static_env." + std::to_string(i));
         while (utils::exists(p.string())) {