如何在 ASP.net 核心中为自定义模型绑定器编写单元测试

Question

我已经为一个属性编写了自定义模型绑定器。现在我正在尝试为相同但无法为模型绑定器创建对象编写单元测试。谁能帮我？下面是我必须编写测试的代码。

public class JourneyTypesModelBinder : IModelBinder
{
    public Task BindModelAsync(ModelBindingContext bindingContext)
    {
        bool IsSingleWay = Convert.ToBoolean((bindingContext.ValueProvider.GetValue("IsSingleWay")).FirstValue);
        bool IsMultiWay = Convert.ToBoolean((bindingContext.ValueProvider.GetValue("IsMultiWay")).FirstValue);
        JourneyTypes journeyType = JourneyTypes.None;
        bool hasJourneyType = Enum.TryParse((bindingContext.ValueProvider.GetValue("JourneyType")).FirstValue, out journeyType);
        if (!hasJourneyType)
        {
            if (IsSingleWay)
                journeyType = JourneyTypes.Single;
            else journeyType = JourneyTypes.MultiWay;
        }
        bindingContext.Result = ModelBindingResult.Success(journeyType);
        return Task.CompletedTask;
    } }  

Answer 1

我已经用Nunit创建了单元测试（这与XUnit几乎相同），并且我用Moq嘲笑了依赖关系。由于在线 C# 编译器，可能会有一些错误，但下面显示的代码会给你这个想法。

[TestFixture]
public class BindModelAsyncTest()
{
    private JourneyTypesModelBinder _modelBinder;
    private Mock<ModelBindingContext> _mockedContext;
    // Setting up things
    public BindModelAsyncTest()
    {
        _modelBinder = new JourneyTypesModelBinder();
        _mockedContext = new Mock<ModelBindingContext>();
        _mockedContext.Setup(c => c.ValueProvider)
            .Returns(new ValueProvider() 
            {
                // Initialize values that are used in this function
                // "IsSingleWay" and the other values
            });
    }
    private JourneyTypesModelBinder CreateService => new JourneyTypesModelBinder();
    [Test]                       
    public Task BindModelAsync_Unittest()
    {
        //Arrange
        //We set variables in setup function.
        var unitUnderTest = CreateService();
        //Act
        var result = unitUnderTest.BindModelAsync(_mockedContext);
        //Assert
        Assert.IsNotNull(result);
        Assert.IsTrue(result is Task.CompletedTask);
    }
} 

Answer 2

您可以使用

实例DefaultModelBindingContext传递到BindModelAsync()：

    [Fact]
    public void JourneyTypesModelBinderTest()
    {
        var bindingContext = new DefaultModelBindingContext();
        var bindingSource = new BindingSource("", "", false, false);
        var routeValueDictionary = new RouteValueDictionary
        {
            {"IsSingleWay", true},
            {"JourneyType", "Single"}
        };
        bindingContext.ValueProvider = new RouteValueProvider(bindingSource, routeValueDictionary);
        var binder = new JourneyTypesModelBinder();
        binder.BindModelAsync(bindingContext);
        Assert.True(bindingContext.Result.IsModelSet);
        Assert.Equal(JourneyTypes.Single, bindingContext.Result.Model);
    }

这可以是使用模拟对象进行bindingContext的替代方法。