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用MOQ模拟嵌套依赖项

moq unit-testing c#

JTech · 技术社区 · 9 年前

我假设MOQ会自动为任何嵌套依赖项创建Mock。

我正在对ASP进行单元测试。Net MVC控制器:

public class TransactionController : Controller
{
    private readonly ITransactionService _transactionService;
    private readonly SearchPanelVmBuilder _searchPanelVmBuilder;
    private readonly TransactionVmsBuilder _transactionVmsBuilder;

    public TransactionController(TransactionVmsBuilder transactionVmsBuilder, ITransactionService transactionService, SearchPanelVmBuilder searchPanelVmBuilder)
    {
        _transactionVmsBuilder = transactionVmsBuilder;
        _transactionService = transactionService;
        _searchPanelVmBuilder = searchPanelVmBuilder;
    }

    // other methods omitted for brevity

    public PartialViewResult SearchPanel()
    {
        var vm = _searchPanelVmBuilder.BuildVm();

        return PartialView("_SearchPanel", vm);
    }
}

单元测试代码:

[Fact]
public void SeachPanel_Calls_BuildSearchPanelVm()
{
    // Arrange
    var mockTransService = new Mock<ITransactionService>();
    var mockTransVmsBuilder = new Mock<TransactionVmsBuilder>();
    var mockSearchPanelVmBuilder = new Mock<SearchPanelVmBuilder>();
    var controller = new TransactionController(mockTransVmsBuilder.Object, mockTransService.Object, mockSearchPanelVmBuilder.Object);

    // Act
    controller.SearchPanel();

    // Assert
    mockSearchPanelVmBuilder.Verify(x => x.BuildVm());
}

MOQ抱怨:

无法实例化类MCIP.Web.UI.ViewModelBuilders.Singular.SearchPanelVmBuilder的代理。找不到无参数构造函数。

它无法实例化代理的类:

public class SearchPanelVmBuilder
{
    private readonly ITransactionTypeService _transactionTypeService;
    private readonly TransactionTypeVmBuilder _transactionTypeVmBuilder;
    private readonly UserProvider _userProvider;

    public SearchPanelVmBuilder(
        UserProvider userProvider,
        ITransactionTypeService transactionTypeService,
        TransactionTypeVmBuilder transactionTypeVmBuilder
        )
    {
        _userProvider = userProvider;
        _transactionTypeService = transactionTypeService;
        _transactionTypeVmBuilder = transactionTypeVmBuilder;
    }

    public virtual SearchPanelVm BuildVm()
    {
        return new SearchPanelVm
        {
            Userlist = _userProvider.GetOperators(),
            TransactionTypes =
                _transactionTypeService.GetAll().Select(x => _transactionTypeVmBuilder.BuildVmFromModel(x)).ToList()
        };
    }
}

其对应的依赖关系:

public class UserProvider
{
    private static int retryCount;

    public virtual List<string> GetOperators()...

    public virtual List<string> GetGroupsForUser(WindowsIdentity identity)...
}

public interface ITransactionTypeService
{
    List<TransactionType> GetAll();
}

public class TransactionTypeVmBuilder
{
    public virtual TransactionTypeVm BuildVmFromModel(TransactionType transactionType)...
}

我做错什么了吗?

我必须明确告诉MOQ开始自动模拟嵌套依赖吗?

或者我必须显式地设置嵌套的Mocks-像这样:

var mockUserProvider = new Mock<UserProvider>();
var mockTransTypeService = new Mock<ITransactionTypeService>();
var mockTransactionTypeVmBuilder = new Mock<TransactionTypeVmBuilder>();
var mockSearchPanelVmBuilder = new Mock<SearchPanelVmBuilder>(mockUserProvider.Object, mockTransTypeService.Object, mockTransactionTypeVmBuilder.Object);

2 回复 | 直到 9 年前

gembird 9 年前

是的,你的假设是正确的。因为班级 SearchPanelVmBuilder 没有为这个类提供无参数构造函数Mock。不能像这样创建:

var mockSearchPanelVmBuilder = new Mock<SearchPanelVmBuilder>()

原因异常: Could not find a parameterless constructor .

相反,通过提供所有参数来创建Mock,如下所示:

UserProvider userProvider = new UserProvider();
Mock<ITransactionTypeService> transactionTypeService = new Mock<ITransactionTypeService>();
TransactionTypeVmBuilder transactionTypeVmBuilder = new TransactionTypeVmBuilder();

// Use constructor with parameters here because SearchPanelVmBuilder 
// doesn't have parameterless constructor
var mockSearchPanelVmBuilder = new Mock<SearchPanelVmBuilder>(
    userProvider, transactionTypeService.Object, transactionTypeVmBuilder);

var mockTransService = new Mock<ITransactionService>();
var mockTransVmsBuilder = new Mock<TransactionVmsBuilder>();

var controller = new TransactionController(
    mockTransVmsBuilder.Object, 
    mockTransService.Object, 
    mockSearchPanelVmBuilder.Object);

然后控制器的实例 TransactionController 可以创建和方法 SearchPanel 可以调用它。

chief7 9 年前

在这种情况下,您需要测试的只是调用BuildVM并返回结果,因此不需要模拟内部依赖关系。在调用SearchPanel方法之前,您确实需要在“排列”部分中为BuildVM方法设置一个返回值。

mockSearchPanelVmBuilder.Setup(x => x.BuildVM()).Returns(mockSearchPanelVM);

因为如果不设置返回值,则会模拟类和虚拟方法,所以实际的实现将运行。对于接口,将抛出一个错误,指示您应该设置一个返回值。