c# - AutoFixture CompositeDataAttribute 不适用于 PropertyDataAttribute

Question

我正在尝试基于此示例中的 CompositeDataAttribute 创建 AutoPropertyDataAttribute AutoFixture: PropertyData and heterogeneous parameters .

它对单组参数有效，但对更多参数组无效。这是代码:

public static IEnumerable<object[]> NumericSequence
{
    get
    {
        yield return new object[] {1};
        //yield return new object[] {2};
    }
}

[Theory]
[AutoPropertyData("NumericSequence")]
public void Test(int? p1, int? p2, int? p3)
{
    Assert.NotNull(p1);
    Assert.NotNull(p2);
}

public class AutoPropertyDataAttribute : CompositeDataAttribute
{
    public AutoPropertyDataAttribute(string propertyName)
        : base(
              new DataAttribute[] { 
                  new PropertyDataAttribute(propertyName), 
                  new AutoDataAttribute()
              })
    {
    }
}

尝试取消注释第二个 yield 将中断测试并显示消息:

System.InvalidOperationException: Expected 2 parameters, got 1 parameters
   at Ploeh.AutoFixture.Xunit.CompositeDataAttribute.<GetData>d__0.MoveNext()
   at Xunit.Extensions.TheoryAttribute.<GetData>d__7.MoveNext()
   at Xunit.Extensions.TheoryAttribute.EnumerateTestCommands(IMethodInfo method)

ClassDataAttribute 也是如此

Answer 1

我遇到了这个问题并决定实现一个自定义的 DataAttribute 来解决这个问题。我不能使用任何一个属性作为基类(原因如下)所以我只是从每个属性的源中获取我需要的东西。谢谢OSS :)

注意事项:

• 我想稍微改变一下语义，这样我就可以选择生成单个对象而不是数组。只是让单对象参数的代码看起来更整洁。这意味着我不能将 PropertyDataAttribute 用作基类
• 每次生成一组新参数时都需要创建夹具。这意味着我不能将 AutoDataAttribute 用作基类

Gist

或下面的内联源代码:

public class AutoPropertyDataAttribute : DataAttribute
{
    private readonly string _propertyName;
    private readonly Func<IFixture> _createFixture;

    public AutoPropertyDataAttribute(string propertyName)
        : this(propertyName, () => new Fixture())
    { }

    protected AutoPropertyDataAttribute(string propertyName, Func<IFixture> createFixture)
    {
        _propertyName = propertyName;
        _createFixture = createFixture;
    }

    public Type PropertyHost { get; set; }

    private IEnumerable<object[]> GetAllParameterObjects(MethodInfo methodUnderTest)
    {
        var type = PropertyHost ?? methodUnderTest.DeclaringType;
        var property = type.GetProperty(_propertyName, BindingFlags.Static | BindingFlags.Public | BindingFlags.FlattenHierarchy);

        if (property == null)
            throw new ArgumentException(string.Format("Could not find public static property {0} on {1}", _propertyName, type.FullName));
        var obj = property.GetValue(null, null);
        if (obj == null)
            return null;

        var enumerable = obj as IEnumerable<object[]>;
        if (enumerable != null)
            return enumerable;

        var singleEnumerable = obj as IEnumerable<object>;
        if (singleEnumerable != null)
            return singleEnumerable.Select(x => new[] {x});

        throw new ArgumentException(string.Format("Property {0} on {1} did not return IEnumerable<object[]>", _propertyName, type.FullName));
    }

    private object[] GetObjects(object[] parameterized, ParameterInfo[] parameters, IFixture fixture)
    {
        var result = new object[parameters.Length];

        for (int i = 0; i < parameters.Length; i++)
        {
            if (i < parameterized.Length)
                result[i] = parameterized[i];
            else
                result[i] = CustomizeAndCreate(fixture, parameters[i]);
        }

        return result;
    }

    private object CustomizeAndCreate(IFixture fixture, ParameterInfo p)
    {
        var customizations = p.GetCustomAttributes(typeof (CustomizeAttribute), false)
            .OfType<CustomizeAttribute>()
            .Select(attr => attr.GetCustomization(p));

        foreach (var c in customizations)
        {
            fixture.Customize(c);
        }

        var context = new SpecimenContext(fixture);
        return context.Resolve(p);
    }

    public override IEnumerable<object[]> GetData(MethodInfo methodUnderTest, Type[] parameterTypes)
    {
        foreach (var values in GetAllParameterObjects(methodUnderTest))
        {
            yield return GetObjects(values, methodUnderTest.GetParameters(), _createFixture());
        }
    }
}