diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index ddcd2cc387..f422f2feb6 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -880,6 +880,8 @@ if os.name == 'nt':
                   'Unicode filename tests may not be effective'
                   % (TESTFN_UNENCODABLE, TESTFN_ENCODING))
             TESTFN_UNENCODABLE = None
+elif sys.platform == 'emscripten':
+    pass
 # Mac OS X denies unencodable filenames (invalid utf-8)
 elif sys.platform != 'darwin':
     try: