WebApi的一种集成测试写法(in-memory)
大家是如何对webApi写测试的呢？
1.利用Fiddler直接做请求，观察response的内容。
2.利用Httpclient做请求，断言response的内容。
3.直接调用webApi的action,这种方式的测试跟真实的调用还是有一定差距，不够完美。
接下来我介绍一种webApi的in-memory调用方法，也能够达到对webApi的测试，并且由于是in-memory调用，效率也比较高，非常适写单元测试。本文参考了In memory client, host and integration testing of your Web API service。
一、首先写一个OrderController用来做测试用
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public class OrderController : ApiController { // GET api/order public Order Get() { return new Order(){Id = 1,Descriptions = "descriptions",Name = "name"}; } // GET api/order/5 public string Get(int id) { return "value"; } // POST api/order public Order Post(Order order) { return order; } // DELETE api/order/5 public void Delete(int id) { } } |
二、WebApi的请求过程
webApi的核心是对消息的管道处理，整个核心是有一系列消息处理器(HttpMessageHandler)首尾连接的双向管道，管道头为HttpServer,管道尾为HttpControllerDispatcher,HttpControllerDispatcher负责对controller的激活和action的执行，然后相应的消息逆向流出管道。
所以我们可以利用HttpMessageInvoker将一个请求消息HttpRequestMessage发送到管道中，最后收到的消息HttpResponseMessage就代表一个真实的请求响应。
三、Get请求的测试
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[Test]public void GetTest(){ HttpConfiguration config = new HttpConfiguration(); WebApiConfig.Register(config); config.IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Always; HttpServer server = new HttpServer(config); HttpMessageInvoker messageInvoker = new HttpMessageInvoker(server); CancellationTokenSource cts = new CancellationTokenSource(); HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Get, baseAddress + "api/order"); using (HttpResponseMessage response = messageInvoker.SendAsync(request, cts.Token).Result) { var content = response.Content.ReadAsStringAsync().Result; var result = JsonConvert.DeserializeObject<Order>(content); result.Name.Should().Be("name"); }} |
四、Post请求的测试
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[Test]public void PostTest(){ HttpConfiguration config = new HttpConfiguration(); WebApiConfig.Register(config); config.IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Always; HttpServer server = new HttpServer(config); HttpMessageInvoker messageInvoker = new HttpMessageInvoker(server); CancellationTokenSource cts = new CancellationTokenSource(); HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, baseAddress + "api/order"); var order = new Order() { Id = 1, Name = "orderName", Descriptions = "orderDescriptions" }; request.Content = new ObjectContent<Order>(order, new JsonMediaTypeFormatter()); using (HttpResponseMessage response = messageInvoker.SendAsync(request, cts.Token).Result) { var content = JsonConvert.SerializeObject(order, new JsonSerializerSettings() { ContractResolver = new CamelCasePropertyNamesContractResolver() }); response.Content.ReadAsStringAsync().Result.Should().Be(content); }} |
四、重构
可以看到这两个测试大部分的代码是相同的，都是用来发送请求。因此我们提取一个webApiTestBase类，该基类可以提供InvokeGetRequest,InvokePostRequest,InvokePutRequest等方法
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public abstract class ApiTestBase { public abstract string GetBaseAddress(); protected TResult InvokeGetRequest<TResult>(string api) { using (var invoker = CreateMessageInvoker()) { using (var cts = new CancellationTokenSource()) { var request = new HttpRequestMessage(HttpMethod.Get, GetBaseAddress() + api); using (HttpResponseMessage response = invoker.SendAsync(request, cts.Token).Result) { var result = response.Content.ReadAsStringAsync().Result; return JsonConvert.DeserializeObject<TResult>(result); } } } } protected TResult InvokePostRequest<TResult, TArguemnt>(string api, TArguemnt arg) { var invoker = CreateMessageInvoker(); using (var cts = new CancellationTokenSource()) { var request = new HttpRequestMessage(HttpMethod.Post, GetBaseAddress() + api); request.Content = new ObjectContent<TArguemnt>(arg, new JsonMediaTypeFormatter()); using (HttpResponseMessage response = invoker.SendAsync(request, cts.Token).Result) { var result = response.Content.ReadAsStringAsync().Result; return JsonConvert.DeserializeObject<TResult>(result); } } } private HttpMessageInvoker CreateMessageInvoker() { var config = new HttpConfiguration(); WebApiConfig.Register(config); var server = new HttpServer(config); var messageInvoker = new HttpMessageInvoker(server); return messageInvoker; } } |
有了这个基类，我们写测试只需要重写方法GetBaseAddress()，然后直接调用基类方法并进行断言即可
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[TestFixture] public class OrderApiTests:ApiTestBase { public override string GetBaseAddress() { } [Test] public void Should_get_order_successfully() { var result = InvokeGetRequest<Order>("api/order"); result.Name.Should().Be("name"); result.Descriptions.Should().Be("descriptions"); result.Id.Should().Be(1); } [Test] public void Should_post_order_successfully() { var newOrder=new Order(){Name = "newOrder",Id = 100,Descriptions = "new-order-description"}; var result = InvokePostRequest<Order,Order>("api/order", newOrder); result.Name.Should().Be("newOrder"); result.Id.Should().Be(100); result.Descriptions.Should().Be("new-order-description"); } } |
是不是干净多了。
这种in-memory的测试方案有什么优点和缺点呢？
优点：
1.模拟真实调用，需要传入api地址即可得到结果，由于整个调用是in-memory的，所有效率很高，很适合集成测试。
2.整个测试时可以调试的，可以直接从单元测试调试进去，如果你写一个httpClient的测试，需要把webApi启动起来，然后。。。麻烦
缺点：我觉得原文作者说的那些缺点都可以忽略不计^_^