如何在ASP中测试反序列化.. NET Web API

Question

在Web API中编写反序列化JSON对象的单元测试的正确方法是什么?

在我的应用程序中，我注意到Web API试图通过调用JsonMeadiaTypeFormatter.ReadFromAsync来反序列化来自请求体的对象参数。我试图隔离问题，所以我写了这些测试。ReadTestItem失败。另一个例子通过了ReadInt，所以看起来我在正确的轨道上，但我不确定这是否是Web API真正在做的。

EDIT: code fixed and FormatterConfig add

class TestClass
{
    public string Type { get; set; }
    public string Value { get; set; }
}
[TestClass]
public class FormatterTest
{
    [TestMethod]
    public void ReadTestItem()
    {
        MediaTypeFormatterCollection formatters = new MediaTypeFormatterCollection();
        FormatterConfig.RegisterGlobalFormatters(formatters);
        JsonMediaTypeFormatter formatter = formatters[0] as JsonMediaTypeFormatter;
        Stream s = GenerateStreamFromString("{ type: "Equal", value: "1" }");
        var content = new StreamContent(s);
        var logger = new Mock<IFormatterLogger>().Object;
        var task = formatter.ReadFromStreamAsync(typeof(TestClass), s, content, logger);
        TestClass result = task.Result as TestClass;
        Assert.AreEqual("Equal", result.Type);
        Assert.AreEqual("1", result.Value);
    }
    [TestMethod]
    public void TestReadInt()
    {
        MediaTypeFormatterCollection formatters = new MediaTypeFormatterCollection();
        FormatterConfig.RegisterGlobalFormatters(formatters);
        JsonMediaTypeFormatter formatter = formatters[0] as JsonMediaTypeFormatter;
        Stream s = GenerateStreamFromString("2");
        var content = new StreamContent(s);
        var logger = new Mock<IFormatterLogger>().Object;
        var task = formatter.ReadFromStreamAsync(typeof(int), s, content, logger);
        Assert.AreEqual(2, task.Result);
    }
    public Stream GenerateStreamFromString(string s)
    {
        MemoryStream stream = new MemoryStream();
        StreamWriter writer = new StreamWriter(stream);
        writer.Write(s);
        writer.Flush();
        stream.Position = 0;
        return stream;
    }
}

下面是格式化器的配置:

public class FormatterConfig
{
    public static void RegisterGlobalFormatters(MediaTypeFormatterCollection formatters)
    {
        var jsonSerializerSettings = formatters.JsonFormatter.SerializerSettings;
        jsonSerializerSettings.Converters.Add(new IsoDateTimeConverter());
        // serialize every enum as a string
        jsonSerializerSettings.Converters.Add(new Newtonsoft.Json.Converters.StringEnumConverter());
        // include null value fields
        jsonSerializerSettings.NullValueHandling = NullValueHandling.Ignore;
        // use camel case
        jsonSerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();
        // indented formatting
        bool indent;
        Boolean.TryParse(ConfigurationManager.AppSettings["dex.indentjson"], out indent);
        formatters.JsonFormatter.Indent = indent;
        formatters.Remove(formatters.XmlFormatter);
    }
}

Answer 1

我觉得这个方法不错。注意到ReadFromStreamAsync在请求体上被调用是正确的。这里有两件奇怪的事情:

您传递给第一个测试的类型是FilterItemDTO。但是你期望结果是一个TestClass?传递给格式化程序的任何类型都是您应该期望反序列化的类型。你是否打算将TestClass传递给ReadFromStreamAsync ?

• TestClass有成员Type和Value，所以是Json。. NET将期望JSON中的成员"Type"one_answers"Value"，而不是"Type"one_answers"Value"。外壳很重要。但是有一种简单的方法可以使用这行代码获得驼峰式大小写:

  config.Formatters.JsonFormatter.SerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();