diff --git a/Lib/test/test_userstring.py b/Lib/test/test_userstring.py
new file mode 100644
index 000000000..b6c11cc4e
--- /dev/null
+++ b/Lib/test/test_userstring.py
@@ -0,0 +1,84 @@
+# UserString is a wrapper around the native builtin string type.
+# UserString instances should behave similar to builtin string objects.
+
+import unittest
+from test import string_tests
+
+from collections import UserString
+
+class UserStringTest(
+    string_tests.CommonTest,
+    string_tests.MixinStrUnicodeUserStringTest,
+    unittest.TestCase
+    ):
+
+    type2test = UserString
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_removeprefix(self):
+        super().test_removeprefix()
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_removesuffix(self):
+        super().test_removesuffix()
+
+    # Overwrite the three testing methods, because UserString
+    # can't cope with arguments propagated to UserString
+    # (and we don't test with subclasses)
+    def checkequal(self, result, object, methodname, *args, **kwargs):
+        result = self.fixtype(result)
+        object = self.fixtype(object)
+        # we don't fix the arguments, because UserString can't cope with it
+        realresult = getattr(object, methodname)(*args, **kwargs)
+        self.assertEqual(
+            result,
+            realresult
+        )
+
+    def checkraises(self, exc, obj, methodname, *args):
+        obj = self.fixtype(obj)
+        # we don't fix the arguments, because UserString can't cope with it
+        with self.assertRaises(exc) as cm:
+            getattr(obj, methodname)(*args)
+        self.assertNotEqual(str(cm.exception), '')
+
+    def checkcall(self, object, methodname, *args):
+        object = self.fixtype(object)
+        # we don't fix the arguments, because UserString can't cope with it
+        getattr(object, methodname)(*args)
+
+    def test_rmod(self):
+        class ustr2(UserString):
+            pass
+
+        class ustr3(ustr2):
+            def __rmod__(self, other):
+                return super().__rmod__(other)
+
+        fmt2 = ustr2('value is %s')
+        str3 = ustr3('TEST')
+        self.assertEqual(fmt2 % str3, 'value is TEST')
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_encode_default_args(self):
+        self.checkequal(b'hello', 'hello', 'encode')
+        # Check that encoding defaults to utf-8
+        self.checkequal(b'\xf0\xa3\x91\x96', '\U00023456', 'encode')
+        # Check that errors defaults to 'strict'
+        self.checkraises(UnicodeError, '\ud800', 'encode')
+
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
+    def test_encode_explicit_none_args(self):
+        self.checkequal(b'hello', 'hello', 'encode', None, None)
+        # Check that encoding defaults to utf-8
+        self.checkequal(b'\xf0\xa3\x91\x96', '\U00023456', 'encode', None, None)
+        # Check that errors defaults to 'strict'
+        self.checkraises(UnicodeError, '\ud800', 'encode', None, None)
+
+
+if __name__ == "__main__":
+    unittest.main()