Misc typing fixes for tests, part 2 of N (#11330)

tests/rest/client/utils.py

@@ -28,11 +28,12 @@ from typing import (
     MutableMapping,
     Optional,
     Tuple,
-    Union,
+    overload,
 )
 from unittest.mock import patch
 
 import attr
+from typing_extensions import Literal
 
 from twisted.web.resource import Resource
 from twisted.web.server import Site
@@ -55,6 +56,32 @@ class RestHelper:
     site = attr.ib(type=Site)
     auth_user_id = attr.ib()
 
+    @overload
+    def create_room_as(
+        self,
+        room_creator: Optional[str] = ...,
+        is_public: Optional[bool] = ...,
+        room_version: Optional[str] = ...,
+        tok: Optional[str] = ...,
+        expect_code: Literal[200] = ...,
+        extra_content: Optional[Dict] = ...,
+        custom_headers: Optional[Iterable[Tuple[AnyStr, AnyStr]]] = ...,
+    ) -> str:
+        ...
+
+    @overload
+    def create_room_as(
+        self,
+        room_creator: Optional[str] = ...,
+        is_public: Optional[bool] = ...,
+        room_version: Optional[str] = ...,
+        tok: Optional[str] = ...,
+        expect_code: int = ...,
+        extra_content: Optional[Dict] = ...,
+        custom_headers: Optional[Iterable[Tuple[AnyStr, AnyStr]]] = ...,
+    ) -> Optional[str]:
+        ...
+
     def create_room_as(
         self,
         room_creator: Optional[str] = None,
@@ -64,7 +91,7 @@ class RestHelper:
         expect_code: int = 200,
         extra_content: Optional[Dict] = None,
         custom_headers: Optional[Iterable[Tuple[AnyStr, AnyStr]]] = None,
-    ) -> str:
+    ) -> Optional[str]:
         """
         Create a room.
 
@@ -107,6 +134,8 @@ class RestHelper:
 
         if expect_code == 200:
             return channel.json_body["room_id"]
+        else:
+            return None
 
     def invite(self, room=None, src=None, targ=None, expect_code=200, tok=None):
         self.change_membership(
@@ -176,7 +205,7 @@ class RestHelper:
         extra_data: Optional[dict] = None,
         tok: Optional[str] = None,
         expect_code: int = 200,
-        expect_errcode: str = None,
+        expect_errcode: Optional[str] = None,
     ) -> None:
         """
         Send a membership state event into a room.
@@ -260,9 +289,7 @@ class RestHelper:
         txn_id=None,
         tok=None,
         expect_code=200,
-        custom_headers: Optional[
-            Iterable[Tuple[Union[bytes, str], Union[bytes, str]]]
-        ] = None,
+        custom_headers: Optional[Iterable[Tuple[AnyStr, AnyStr]]] = None,
     ):
         if txn_id is None:
             txn_id = "m%s" % (str(time.time()))
@@ -509,7 +536,7 @@ class RestHelper:
             went.
         """
 
-        cookies = {}
+        cookies: Dict[str, str] = {}
 
         # if we're doing a ui auth, hit the ui auth redirect endpoint
         if ui_auth_session_id:
@@ -631,7 +658,13 @@ class RestHelper:
 
         # hit the redirect url again with the right Host header, which should now issue
         # a cookie and redirect to the SSO provider.
-        location = channel.headers.getRawHeaders("Location")[0]
+        def get_location(channel: FakeChannel) -> str:
+            location_values = channel.headers.getRawHeaders("Location")
+            # Keep mypy happy by asserting that location_values is nonempty
+            assert location_values
+            return location_values[0]
+
+        location = get_location(channel)
         parts = urllib.parse.urlsplit(location)
         channel = make_request(
             self.hs.get_reactor(),
@@ -645,7 +678,7 @@ class RestHelper:
 
         assert channel.code == 302
         channel.extract_cookies(cookies)
-        return channel.headers.getRawHeaders("Location")[0]
+        return get_location(channel)
 
     def initiate_sso_ui_auth(
         self, ui_auth_session_id: str, cookies: MutableMapping[str, str]