public async Task Given_A_Deck_If_User_Is_Not_Owner_Should_Not_Invoke_DeleteDeckByIdAndUserId() { // Arrange var deck = new DeckInputModel { MainDeck = new List <CardInputModel>() }; var command = new DeleteDeckCommand { Deck = deck }; _userService.IsUserDeckOwner(Arg.Any <string>(), Arg.Any <long>()).Returns(false); // Act await _sut.Handle(command, CancellationToken.None); // Assert await _deckService.DidNotReceive().DeleteDeckByIdAndUserId(Arg.Any <string>(), Arg.Any <long>()); }