public async Task Logout()
        {
            //Setup
            var sessionMock  = new Mock <ISessionService>();
            var eventAggMock = new Mock <IEventAggregator>();
            var clientMock   = new Mock <IApiClient>();
            var model        = new ServerListViewModel(sessionMock.Object, eventAggMock.Object, clientMock.Object);

            //Act
            model.Servers = new BindableCollection <Server>();
            model.Logout();

            //Assert
            sessionMock.Verify(m => m.Logout(), Times.Once);
            Assert.IsNull(model.Servers);
        }