public WriteableApiClientTests(ITestOutputHelper output,
                                ApiLauncherFactory <TStartup> fixture,
                                string testUser = "******")
 {
     Output       = output;
     ApiClient    = TestApiClientFactory.CreateWriteableClient <TClient, TStartup>(fixture, testUser);
     HttpClient   = ApiClient.HttpClient;
     InstanceName = ApiClient.GetInstanceName();
 }