test performance: Pass in users to api_* helpers.

This reduces query counts in some cases, since
we no longer need to look up the user again. In
particular, it reduces some noise when we
count queries for O(N)-related tests.

The query count is usually reduced by 2 per
API call.  We no longer need to look up Realm
and UserProfile.  In most cases we are saving
these lookups for the whole tests, since we
usually already have the `user` objects for
other reasons.  In a few places we are simply
moving where that query happens within the
test.

In some places I shorten names like `test_user`
or `user_profile` to just be `user`.

zerver/lib/test_classes.py

@@ -430,14 +430,16 @@ class ZulipTestCase(TestCase):
 
         return self.encode_credentials(uuid, api_key)
 
+    def encode_user(self, user: UserProfile) -> str:
+        email = user.delivery_email
+        api_key = user.api_key
+        return self.encode_credentials(email, api_key)
+
     def encode_email(self, email: str, realm: str="zulip") -> str:
+        # TODO: use encode_user where possible
         assert '@' in email
-        if email in self.API_KEYS:
-            api_key = self.API_KEYS[email]
-        else:
-            user = get_user_by_delivery_email(email, get_realm(realm))
-            api_key = get_api_key(user)
-            self.API_KEYS[email] = api_key
+        user = get_user_by_delivery_email(email, get_realm(realm))
+        api_key = get_api_key(user)
 
         return self.encode_credentials(email, api_key)
 
@@ -456,20 +458,20 @@ class ZulipTestCase(TestCase):
         kwargs['HTTP_AUTHORIZATION'] = self.encode_uuid(identifier)
         return self.client_post(*args, **kwargs)
 
-    def api_get(self, identifier: str, *args: Any, **kwargs: Any) -> HttpResponse:
-        kwargs['HTTP_AUTHORIZATION'] = self.encode_email(identifier, kwargs.get('subdomain', 'zulip'))
+    def api_get(self, user: UserProfile, *args: Any, **kwargs: Any) -> HttpResponse:
+        kwargs['HTTP_AUTHORIZATION'] = self.encode_user(user)
         return self.client_get(*args, **kwargs)
 
-    def api_post(self, identifier: str, *args: Any, **kwargs: Any) -> HttpResponse:
-        kwargs['HTTP_AUTHORIZATION'] = self.encode_email(identifier, kwargs.get('subdomain', 'zulip'))
+    def api_post(self, user: UserProfile, *args: Any, **kwargs: Any) -> HttpResponse:
+        kwargs['HTTP_AUTHORIZATION'] = self.encode_user(user)
         return self.client_post(*args, **kwargs)
 
-    def api_patch(self, identifier: str, *args: Any, **kwargs: Any) -> HttpResponse:
-        kwargs['HTTP_AUTHORIZATION'] = self.encode_email(identifier, kwargs.get('subdomain', 'zulip'))
+    def api_patch(self, user: UserProfile, *args: Any, **kwargs: Any) -> HttpResponse:
+        kwargs['HTTP_AUTHORIZATION'] = self.encode_user(user)
         return self.client_patch(*args, **kwargs)
 
-    def api_delete(self, identifier: str, *args: Any, **kwargs: Any) -> HttpResponse:
-        kwargs['HTTP_AUTHORIZATION'] = self.encode_email(identifier, kwargs.get('subdomain', 'zulip'))
+    def api_delete(self, user: UserProfile, *args: Any, **kwargs: Any) -> HttpResponse:
+        kwargs['HTTP_AUTHORIZATION'] = self.encode_user(user)
         return self.client_delete(*args, **kwargs)
 
     def get_streams(self, user_profile: UserProfile) -> List[str]:
@@ -696,7 +698,7 @@ class ZulipTestCase(TestCase):
         post_data = {'subscriptions': ujson.dumps([{"name": stream} for stream in streams]),
                      'invite_only': ujson.dumps(invite_only)}
         post_data.update(extra_post_data)
-        result = self.api_post(user.email, "/api/v1/users/me/subscriptions", post_data, **kwargs)
+        result = self.api_post(user, "/api/v1/users/me/subscriptions", post_data, **kwargs)
         return result
 
     def check_user_subscribed_only_to_streams(self, user_name: str,
@@ -865,8 +867,8 @@ class WebhookTestCase(ZulipTestCase):
         super().setUp()
         self.url = self.build_webhook_url()
 
-    def api_stream_message(self, email: str, *args: Any, **kwargs: Any) -> HttpResponse:
-        kwargs['HTTP_AUTHORIZATION'] = self.encode_email(email)
+    def api_stream_message(self, user: UserProfile, *args: Any, **kwargs: Any) -> HttpResponse:
+        kwargs['HTTP_AUTHORIZATION'] = self.encode_user(user)
         return self.send_and_test_stream_message(*args, **kwargs)
 
     def send_and_test_stream_message(self, fixture_name: str, expected_topic: Optional[str]=None,