.net - 在 .NET 5 中测试 Azure 函数

Question

我已经开始开发 Azure Functions，现在我想创建我的第一个单元/集成测试，但我完全陷入困境。虽然我有一个非常简单的函数，带有 HTTP 触发器、HTTP 和存储队列输出，但测试它似乎非常复杂。

代码(简化):

public class MyOutput
{
    [QueueOutput("my-queue-name", Connection = "my-connection")]
    public string QueueMessage { get; set; }

    public HttpResponseData HttpResponse { get; set; }
}

public static class MyFunction
{
    [Function(nameof(MyFunction))]
    public static async Task<MyOutput> Run(
        [HttpTrigger(AuthorizationLevel.Function, "POST")] HttpRequestData req,
        FunctionContext executionContext)
    {
        var logger = executionContext.GetLogger(nameof(MyFunction));
        logger.LogInformation("Received {Bytes} bytes", req.Body.Length);
        //implementation
    }
}

现在我希望构建这样的测试:

public async Task Test()
{
    var response = await MyFunction.Run(..., ...);
    Assert.IsNotNull(response);
}

在互联网上寻找了几个小时的好方法后，我仍然没有找到模拟 HttpRequestData 和 FunctionContext 的方法。我还通过设置服务器来寻找完整的集成测试，但这看起来非常复杂。我最终得到的唯一结果是:https://github.com/Azure/azure-functions-dotnet-worker/blob/72b9d17a485eda1e6e3626a9472948be1152ab7d/test/E2ETests/E2ETests/HttpEndToEndTests.cs

是否有人有在 .NET 5 中测试 Azure Functions 的经验，谁可以帮助我朝正确的方向前进？有没有关于如何在 dotnet-isolated 中测试 Azure Function 的好文章或示例？

Answer 1

解决方案1

我终于能够 mock 整件事了。绝对不是我最好的作品，可以使用一些重构，但至少我得到了一个工作原型(prototype):

var serviceCollection = new ServiceCollection();
serviceCollection.AddScoped<ILoggerFactory, LoggerFactory>();
var serviceProvider = serviceCollection.BuildServiceProvider();

var context = new Mock<FunctionContext>();
context.SetupProperty(c => c.InstanceServices, serviceProvider);

var byteArray = Encoding.ASCII.GetBytes("test");
var bodyStream = new MemoryStream(byteArray);

var request = new Mock<HttpRequestData>(context.Object);
request.Setup(r => r.Body).Returns(bodyStream);
request.Setup(r => r.CreateResponse()).Returns(() =>
{
    var response = new Mock<HttpResponseData>(context.Object);
    response.SetupProperty(r => r.Headers, new HttpHeadersCollection());
    response.SetupProperty(r => r.StatusCode);
    response.SetupProperty(r => r.Body, new MemoryStream());
    return response.Object;
});

var result = await MyFunction.Run(request.Object, context.Object);
result.HttpResponse.Body.Seek(0, SeekOrigin.Begin);
var reader = new StreamReader(result.HttpResponse.Body);
var responseBody = await reader.ReadToEndAsync();

Assert.IsNotNull(result);
Assert.AreEqual(HttpStatusCode.OK, result.HttpResponse.StatusCode);
Assert.AreEqual("Hello test", responseBody);

解决方案2

我通过依赖注入(inject)添加了记录器，并为 HttpRequestData 和 HttpResponseData 创建了自己的实现。这更容易重用，并使测试本身更干净。

public class FakeHttpRequestData : HttpRequestData
{
        public FakeHttpRequestData(FunctionContext functionContext, Uri url, Stream body = null) : base(functionContext)
    {
        Url = url;
        Body = body ?? new MemoryStream();
    }

    public override Stream Body { get; } = new MemoryStream();

    public override HttpHeadersCollection Headers { get; } = new HttpHeadersCollection();

    public override IReadOnlyCollection<IHttpCookie> Cookies { get; }

    public override Uri Url { get; }

    public override IEnumerable<ClaimsIdentity> Identities { get; }

    public override string Method { get; }

    public override HttpResponseData CreateResponse()
    {
        return new FakeHttpResponseData(FunctionContext);
    }
}

public class FakeHttpResponseData : HttpResponseData
{
    public FakeHttpResponseData(FunctionContext functionContext) : base(functionContext)
    {
    }

    public override HttpStatusCode StatusCode { get; set; }
    public override HttpHeadersCollection Headers { get; set; } = new HttpHeadersCollection();
    public override Stream Body { get; set; } = new MemoryStream();
    public override HttpCookies Cookies { get; }
}

现在测试看起来像这样:

// Arrange
var body = new MemoryStream(Encoding.ASCII.GetBytes("{ \"test\": true }"))
var context = new Mock<FunctionContext>();
var request = new FakeHttpRequestData(
                context.Object, 
                new Uri("https://stackoverflow.com"), 
                body);

// Act
var function = new MyFunction(new NullLogger<MyFunction>());
var result = await function.Run(request);
result.HttpResponse.Body.Position = 0;

// Assert
var reader = new StreamReader(result.HttpResponse.Body);
var responseBody = await reader.ReadToEndAsync();
Assert.IsNotNull(result);
Assert.AreEqual(HttpStatusCode.OK, result.HttpResponse.StatusCode);
Assert.AreEqual("Hello test", responseBody);