Fix mismatched stopSyncing call which could cause test pollution

internal/api/rust/rust.go

@@ -186,6 +186,7 @@ func (c *RustClient) StartSyncing(t ct.TestLike) (stopSyncing func(), err error)
 	return func() {
 		t.Logf("%s: Stopping sync service", c.userID)
 		syncService.Stop()
+		syncService.Destroy()
 	}, nil
 }
 

tests/go_templates/login_rust_client_and_send_msg/login_rust_client_and_send_msg.go

@@ -24,8 +24,9 @@ func main() {
 	if err := client.Login(t, cfg); err != nil {
 		panic(err)
 	}
-	client.MustStartSyncing(t)
+	stopSyncing := client.MustStartSyncing(t)
 	defer client.Close(t)
+	defer stopSyncing()
 	roomID := "{{.RoomID}}"
 	fmt.Println("Client logged in. Sending '{{.Body}}' in room {{.RoomID}}")
 	eventID := client.SendMessage(t, "{{.RoomID}}", "{{.Body}}")

tests/room_keys_test.go

@@ -199,11 +199,10 @@ func testRoomKeyIsNotCycledOnClientRestartJS(t *testing.T, clientType api.Client
 
 	// Alice and Bob are in a room.
 	alice := tc.MustLoginClient(t, tc.Alice, clientType, WithPersistentStorage())
+	aliceStopSyncing := alice.MustStartSyncing(t)
 	// no close here as we'll close it in the test mid-way
 	bob := tc.MustLoginClient(t, tc.Bob, clientType)
 	defer bob.Close(t)
-	aliceStopSyncing := alice.MustStartSyncing(t)
-	defer aliceStopSyncing()
 	bobStopSyncing := bob.MustStartSyncing(t)
 	defer bobStopSyncing()
 
@@ -235,6 +234,7 @@ func testRoomKeyIsNotCycledOnClientRestartJS(t *testing.T, clientType api.Client
 		},
 	}, func() {
 		// now alice is going to restart her client
+		aliceStopSyncing()
 		alice.Close(t)
 
 		alice = tc.MustCreateClient(t, tc.Alice, clientType, WithPersistentStorage())

tests/state_synchronisation_test.go

@@ -103,9 +103,10 @@ func testSigkillBeforeKeysUploadResponseRust(t *testing.T, clientType api.Client
 		// now make the same client
 		alice := MustCreateClient(t, clientType, cfg, tc.Deployment.SlidingSyncURL(t))
 		alice.Login(t, cfg) // login should work
-		alice.MustStartSyncing(t)
+		stopSyncing := alice.MustStartSyncing(t)
 		// ensure we see the 2nd keys/upload
 		seenSecondKeysUploadWaiter.Wait(t, 5*time.Second)
+		stopSyncing()
 		alice.Close(t)
 	})
 }