diff --git a/tests/rest/client/test_register.py b/tests/rest/client/test_register.py
index 6e7c0f11df..407dd32a73 100644
--- a/tests/rest/client/test_register.py
+++ b/tests/rest/client/test_register.py
@@ -726,6 +726,47 @@ class RegisterRestServletTestCase(unittest.HomeserverTestCase):
{"errcode": "M_UNKNOWN", "error": "Unable to parse email address"},
)
+ @override_config(
+ {
+ "inhibit_user_in_use_error": True,
+ }
+ )
+ def test_inhibit_user_in_use_error(self):
+ """Tests that the 'inhibit_user_in_use_error' configuration flag behaves
+ correctly.
+ """
+ username = "arthur"
+
+ # Manually register the user, so we know the test isn't passing because of a lack
+ # of clashing.
+ reg_handler = self.hs.get_registration_handler()
+ self.get_success(reg_handler.register_user(username))
+
+ # Check that /available correctly ignores the username provided despite the
+ # username being already registered.
+ channel = self.make_request("GET", "register/available?username=" + username)
+ self.assertEquals(200, channel.code, channel.result)
+
+ # Test that when starting a UIA registration flow the request doesn't fail because
+ # of a conflicting username
+ channel = self.make_request(
+ "POST",
+ "register",
+ {"username": username, "type": "m.login.password", "password": "foo"},
+ )
+ self.assertEqual(channel.code, 401)
+ self.assertIn("session", channel.json_body)
+
+ # Test that finishing the registration fails because of a conflicting username.
+ session = channel.json_body["session"]
+ channel = self.make_request(
+ "POST",
+ "register",
+ {"auth": {"session": session, "type": LoginType.DUMMY}},
+ )
+ self.assertEqual(channel.code, 400, channel.json_body)
+ self.assertEqual(channel.json_body["errcode"], Codes.USER_IN_USE)
+
class AccountValidityTestCase(unittest.HomeserverTestCase):
|