public void LogoutShouldBeEnabledOnlyWhenAuthorized()
{
var authorized = new BehaviorSubject <bool>(true);
_cloud.IsAuthorized.Returns(authorized);
_cloud.SupportsDirectAuth.Returns(true);
var model = BuildProviderViewModel();
model.Logout.CanExecute().Should().BeTrue();
model.Logout.Execute().Subscribe();
authorized.OnNext(false);
_cloud.Received(1).Logout();
model.Logout.CanExecute().Should().BeFalse();
}