public async Task CreatePaymentAsync() { //Arrange var payment = new ProcessPaymentRequest { Amount = 100, Currency = "EUR", FullName = "Dmitriy Purtseladze", CardNumber = "5555-5555-5555-5555", Cvv = 123, Expiry = "08/22" }; //Act await _subject.ProcessPaymentAsync(payment); //Assert await Mediator.Received().Send(Arg.Any <ProcessPaymentCommand>()); }