您如何对 ASP.NET 个 return 匿名对象的核心 MVC 控制器进行单元测试?

How do you unit test ASP.NET Core MVC Controllers that return anonymous objects?

我在单元测试 ASP.NET return 匿名对象的核心 MVC 控制器时遇到问题。单元测试设置在一个单独的项目中,并直接从主项目调用控制器方法。

控制器方法 return IActionResult 但通常这些方法是 OkObjectResultBadRequestObjectResult 对象,它们被转换为具有适当 HTTP 状态的 JSON 响应代码。匿名对象作为 ObjectResult 对象的构造函数参数传递,我正试图针对这些对象进行断言(可通过 ObjectResult.Value 访问)。

我发现这个问题 (how can i access internals in asp.net 5) 的答案是使用动态并添加

[assembly: InternalsVisibleTo("Namespace")]

到AssemblyInfo.cs允许测试项目访问匿名对象的内部对象属性。但是,ASP.NET 核心 MVC 的最新版本没有 AssemblyInfo.cs,并且按照链接问题的答案中的建议添加一个也不起作用。

现在有不同的位置可以添加 InternalsVisibleTo 还是我遗漏了什么?

来自 this answer 的原创想法,采用更通用的方法。使用自定义 DynamicObject 作为通过反射检查值的包装器,无需添加 InternalsVisibleTo

public class DynamicObjectResultValue : DynamicObject, IEquatable<DynamicObjectResultValue> {
    private readonly object value;

    public DynamicObjectResultValue(object value) {
        this.value = value;
    }

    #region Operators
    public static bool operator ==(DynamicObjectResultValue a, DynamicObjectResultValue b) {
        // If both are null, or both are same instance, return true.
        if (System.Object.ReferenceEquals(a, b)) {
            return true;
        }
        // If one is null, but not both, return false.
        if (ReferenceEquals((object)a, null) || ReferenceEquals((object)b, null)) {
            return false;
        }
        // Return true if the fields match:
        return a.value == b.value;
    }

    public static bool operator !=(DynamicObjectResultValue a, DynamicObjectResultValue b) {
        return !(a == b);
    }
    #endregion

    public override IEnumerable<string> GetDynamicMemberNames() {
        return value.GetType().GetProperties().Select(p => p.Name);
    }

    public override bool TryGetMember(GetMemberBinder binder, out object result) {
        //initialize value
        result = null;
        //Search possible matches and get its value
        var property = value.GetType().GetProperty(binder.Name);
        if (property != null) {
            // If the property is found, 
            // set the value parameter and return true. 
            var propertyValue = property.GetValue(value, null);
            result = propertyValue;
            return true;
        }
        // Otherwise, return false. 
        return false;
    }

    public override bool Equals(object obj) {
        if (obj is DynamicObjectResultValue)
            return Equals(obj as DynamicObjectResultValue);
        // If parameter is null return false.
        if (ReferenceEquals(obj, null)) return false;
        // Return true if the fields match:
        return this.value == obj;
    }

    public bool Equals(DynamicObjectResultValue other) {
        // If parameter is null return false.
        if (ReferenceEquals(other, null)) return false;
        // Return true if the fields match:
        return this.value == other.value;
    }

    public override int GetHashCode() {
        return ToString().GetHashCode();
    }

    public override string ToString() {
        return string.Format("{0}", value);
    }
}

假设控制器如下

public class FooController : Controller {

    public IActionResult GetAnonymousObject() {

        var jsonResult = new {
            id = 1,
            name = "Foo",
            type = "Bar"
        };

        return Ok(jsonResult);
    }

    public IActionResult GetAnonymousCollection() {

        var jsonResult = Enumerable.Range(1, 20).Select(x => new {
            id = x,
            name = "Foo" + x,
            type = "Bar" + x
        }).ToList();

        return Ok(jsonResult);
    }
}

测试可能看起来像

[TestMethod]
public void TestDynamicResults() {
    //Arrange
    var controller = new FooController();

    //Act
    var result = controller.GetAnonymousObject() as OkObjectResult;

    //Assert
    dynamic obj = new DynamicObjectResultValue(result.Value);

    Assert.IsNotNull(obj);
    Assert.AreEqual(1, obj.id);
    Assert.AreEqual("Foo", obj.name);
    Assert.AreEqual(3, obj.name.Length);
    Assert.AreEqual("Bar", obj.type);
}

[TestMethod]
public void TestDynamicCollection() {
    //Arrange
    var controller = new FooController();

    //Act
    var result = controller.GetAnonymousCollection() as OkObjectResult;

    //Assert
    Assert.IsNotNull(result, "No ActionResult returned from action method.");
    dynamic jsonCollection = result.Value;
    foreach (dynamic value in jsonCollection) {
        dynamic json = new DynamicObjectResultValue(value);

        Assert.IsNotNull(json.id,
            "JSON record does not contain \"id\" required property.");
        Assert.IsNotNull(json.name,
            "JSON record does not contain \"name\" required property.");
        Assert.IsNotNull(json.type,
            "JSON record does not contain \"type\" required property.");
    }
}