mocking - 方法内部的 FakeItEasy 模拟错误

Question

我有一个我正在尝试测试的方法，需要测试是否引发错误。如果员工存储库抛出错误，我想确保我得到 EmployeeServiceError 回来。我正在使用 FakeItEasy 模拟框架。

这是 FakeItEasy 代码：

//  Arrange
        var service = new EmployeeService(mockEmployeeRepository, mockCryptographer, mockApplicationUserRepository, mockEmployeeAddressRepository);

        IEnumerable<EmployeeDTO> employeeDTOs;

        //  Act
        employeeDTOs = service.GetEmployees();

        //  Assert
// How do I check the EmployeeServiceException thrown?

        A.CallTo(() => mockEmployeeRepository.GetAllForUi())
            .Throws(new NullReferenceException());

这是我正在测试的方法：

public IEnumerable<EmployeeDTO> GetEmployees()
        {
            IEnumerable<EmployeeDTO> employeeDTOs = null;

            try
            {
                var employees = _employeeRepository.GetAllForUi();
                employeeDTOs = Mapper.Map(employees, employeeDTOs);
            }
            catch (Exception exception)
            {
                throw new EmployeeServiceException(exception);
            }

            return employeeDTOs;
        }

Answer 1

使用 xUnit.net，我会这样做：

//  Arrange
A.CallTo(() => mockEmployeeRepository.GetAllForUi())
    .Throws(new NullReferenceException());

var service = new EmployeeService(
    mockEmployeeRepository,
    mockCryptographer,
    mockApplicationUserRepository,
    mockEmployeeAddressRepository);

//  Act
var exception = Record.Exception(() => service.GetEmployees();

//  Assert
Assert.IsType<EmployeeServiceException>(exception);

Record.Exception()是 xUnit.net 的一项功能。也许 NUnit 也有类似的东西。

顺便说一句 - 你不应该Exception在你的方法中捕捉到一般类型GetEmployees()，但这是一个单独的讨论。

Answer 2

This is how I would write it with NUnit:

A.CallTo(() => fakeEmployeeRepository.GetAllForUi())
    .Throws(new NullReferenceException());

var service = new EmployeeService(fakeEmployeeRepository, fakeCryptographer, fakeApplicationUserRepository, fakeEmployeeAddressRepository);

Assert.Throws<EmployeeServiceException>(() => service.GetEmployees());

I renamed the variables since they are not mocks. To prefix them with stub would also work.