public async Task AddPaymentMethod_UserSignedIn_SetsActivePaymentMethodForUser()
{
//Arrange
var fakeMediator = Substitute.For <IMediator>();
var mapper = AutoMapperFactory.CreateValidMapper();
var controller = new PaymentController(
fakeMediator,
mapper);
controller.FakeAuthentication("some-identity-name");
//Act
await controller.AddPaymentMethod("some-payment-method-id");
//Assert
await fakeMediator
.Received(1)
.Send(Arg.Is <SetActivePaymentMethodForUserCommand>(arg =>
arg.PaymentMethodId == "some-payment-method-id"));
}