public async Task HandleShouldReturnOk()
        {
            // Arrange
            var instructionReadRepositoryMock = new Mock <IInstructionReadRepository>();

            instructionReadRepositoryMock.Setup(x => x.ListAsync(It.IsAny <Expression <Func <Instruction, bool> > >(), It.IsAny <int?>(), It.IsAny <int?>())).Returns(Task.FromResult(Enumerable.Empty <Instruction>()));
            var instructionReadRepository = instructionReadRepositoryMock.Object;

            var mapperMock = new Mock <IMapper>();

            mapperMock.Setup(x => x.Map <IEnumerable <InstructionModel> >(It.IsAny <object>())).Returns(Enumerable.Empty <InstructionModel>());
            var mapper = mapperMock.Object;

            var query = new ListInstructionQuery(null, null, null);

            var handler = new ListInstructionQueryHandler(mapper, instructionReadRepository);

            // Act
            var result = await handler.Handle(query, CancellationToken.None);

            // Assert
            result.IsFailure.Should().BeFalse();
            result.Should().BeOfType(typeof(Result <InstructionsModel>));
        }
        public async Task HandleShouldReturnFailWhenDatabaseSpecificErrorOccurs()
        {
            // Arrange
            var instructionReadRepositoryMock = new Mock <IInstructionReadRepository>();

            instructionReadRepositoryMock.Setup(x => x.ListAsync(It.IsAny <Expression <Func <Instruction, bool> > >(), It.IsAny <int?>(), It.IsAny <int?>())).Throws <SomeDatabaseSpecificException>();
            var instructionReadRepository = instructionReadRepositoryMock.Object;

            var mapperMock = new Mock <IMapper>();

            mapperMock.Setup(x => x.Map <IEnumerable <InstructionModel> >(It.IsAny <object>())).Returns(Enumerable.Empty <InstructionModel>());
            var mapper = mapperMock.Object;

            var query = new ListInstructionQuery(null, null, null);

            var handler = new ListInstructionQueryHandler(mapper, instructionReadRepository);

            // Act
            var result = await handler.Handle(query, CancellationToken.None);

            // Assert
            result.IsFailure.Should().BeTrue();
            result.Failures.Should().OnlyContain(x => x.Message == CustomFailures.ListInstructionFailure);
        }