public async Task GetPaymentDetailsCallsThroughToMediator()
{
Guid paymentId = Guid.NewGuid();
var mediator = new Mock <IMediator>();
var sut = new PaymentsController(mediator.Object);
await sut.GetPaymentDetails(paymentId);
mediator.Verify(x => x.Send(It.Is <GetPaymentRequest>(y => y.PaymentId == paymentId), It.IsAny <CancellationToken>()), Times.Once);
}