Fix up "Test that invites can be rescinded over federation"

[erikjohnston]

Follows on from #797, which I merged Too Soon

c.f. element-hq/synapse#18823

[MadLittleMods]

Suggestion:

		t.Run("Non-inviter user cannot rescind invite over federation", func(t *testing.T) {
			t.Parallel()

			// First create a room that Bob is in. This is so that later we can
			// send a message to test that Bob doesn't see the rescission.
			roomID1 := alice.MustCreateRoom(t, map[string]interface{}{
				"preset": "private_chat",
				"invite": []string{bob.UserID},
			})
			since := bob.MustSyncUntil(t, client.SyncReq{}, client.SyncInvitedTo(bob.UserID, roomID1))
			bob.MustJoinRoom(t, roomID1, []spec.ServerName{})

			// Second room which Alice and Alice2 join, Alice2 invites Bob and
			// then Alice kicks him.
			roomID2 := alice.MustCreateRoom(t, map[string]interface{}{
				"preset": "private_chat",
				"invite": []string{alice2.UserID},
			})
			alice2.MustSyncUntil(t, client.SyncReq{}, client.SyncInvitedTo(alice2.UserID, roomID2))
			alice2.MustJoinRoom(t, roomID2, []spec.ServerName{})

			// `alice2` invites bob
			alice2.MustInviteRoom(t, roomID2, bob.UserID)
			bob.MustSyncUntil(t, client.SyncReq{}, client.SyncInvitedTo(bob.UserID, roomID2))

			// `alice`, not the original inviter (`alice2`), kicks bob.
			alice.MustDo(t, "POST", []string{"_matrix", "client", "v3", "rooms", roomID2, "kick"},
				client.WithJSONBody(t, map[string]interface{}{
					"user_id": bob.UserID,
					"reason":  "testing",
				}),
			)

			// Check bob *doesn't* see the rescission.  We do this by sending a message in
			// `roomID1` (on the same homeserver as `roomID2`) and checking that once Bob
			// receives that new message in `roomID1` he still hasn't seen the leave for `roomID2`.
			//
			// Ideally, bob could see the rescission, but currently we have no way to auth
			// that over federation.
			eventID := alice.SendEventSynced(t, roomID1, b.Event{
				Type: "m.room.message",
				Content: map[string]interface{}{
					"body":    "1",
					"msgtype": "m.text",
				},
				Sender: alice.UserID,
			})
			bob.MustSyncUntil(t, client.SyncReq{Since: since}, client.SyncTimelineHasEventID(roomID1, eventID))

			// Check bob is still invited to `roomID2` by doing an initial sync
			bob.MustSyncUntil(t, client.SyncReq{}, client.SyncInvitedTo(bob.UserID, roomID2))
		})