public async Task LogoutCall_Test() { IHttpService httpService = A.Fake <IHttpService>(); IEventAggregator evenAggregator = A.Fake <IEventAggregator>(); httpService = A.Fake <IHttpService>(); ServerListViewModel serverListViewModel = new ServerListViewModel(evenAggregator, httpService); await serverListViewModel.Servers(); A.CallTo(() => httpService.GetAsync <List <Server> >(A <string> ._, A <string> ._)).MustHaveHappened(); }