测试自定义工厂中间件

Question

我正在创建一个 asp.net 核心网络应用程序，它从用户定义的源（配置、数据库等）创建路由。我使用了一种基于中间件工厂的方法，效果很好，但我不知道如何隔离中间件以进行单元/集成测试。我使用来自 HttpContext 的路由数据来验证针对用户定义的配置源的传入请求，所以我需要 HttpContext 来拥有 RouteData，这就是我倾向于使用 xUnit 进行集成测试的原因。

如果我使用通过 AspNetCore.TestHost.TestServer.CreateCLient() 创建的 httpclient 发出请求，我会在整个调用链中工作，这正是我所期望的。我需要做的是终止中间件或为 HttpContext 提供 RouteData。

我使用 AutoFixture 和 DefaultHttpContext() 尝试了一个丑陋的单元测试，但正如预期的那样，我的 HttpContext 上没有任何 RouteData，所以我的测试永远无法通过。

中间件

public async Task InvokeAsync(HttpContext context, RequestDelegate next)
{
     try 
     {
         if (_flowApis.Count == 0)
              throw new ArgumentNullException();

          var doesMatch = false;
          var routeData = context.GetRouteData();

          foreach (var api in _flowApis)
          {
             if (!RequestType.IsValidRequestType(api.Request.Type))
                  throw new InvalidOperationException();
             else
                 foreach (Route route in routeData.Routers.Where(r => r.GetType() == typeof(Route)))
                 {
                     if (route.RouteTemplate == api.Route)
                     {
                        if (route.Constraints.TryGetValue("httpMethod", out IRouteConstraint routeConstraint))
                        {
                             var value = (HttpMethodRouteConstraint)routeConstraint;
                             if (value.AllowedMethods.Contains(api.Method))
                             {
                                 doesMatch = true;
                                 var routeValues = GetRouteValues(routeData);
                                 var request = new Core.Request(context.Request, api, routeValues);
                                        context.Items.Add(nameof(Core.Request), request);
                                        break;
                                    }
                                }
                            }
                        }
                    if (doesMatch)
                        break;
                }

                if (!doesMatch)
                {
                    context.Response.StatusCode = 404;
                    await context.Response.WriteAsync("", new CancellationToken());
                }
                else
                    await next(context);
            }
            catch(ArgumentNullException ex)
            {
                var mex = new MiddleWareException<MatchRouteToFlowApiMiddleware>("Flow Configuration in app.settings has not been set.", ex);
                context.Response.StatusCode = 500;
                await context.Response.WriteAsync("", new CancellationToken());
            }
            catch (InvalidOperationException ex)
            {
                var mex = new MiddleWareException<MatchRouteToFlowApiMiddleware>("Invalid Request Type", ex);
                context.Response.StatusCode = 500;
                await context.Response.WriteAsync("", new CancellationToken());
            }
        }

单元测试

[TestMethod]
public async Task Request_path_matches_an_api_route_and_method()
{
var fixture = ScaffoldFixture();
var flowApi = fixture.Build<FlowApi>()
                     .With(p => p.Route, "/some/path")
                     .With(m => m.Method, "GET")
                     .Create();
var flowApiRequest = fixture.Build<Request>()
                            .With(t => t.Type, "CData")
                            .Create();
flowApi.Request = flowApiRequest;
var flowConfiguration = fixture.Create<FlowConfiguration>();
flowConfiguration.FlowApis.Clear();
flowConfiguration.FlowApis.Add(flowApi);

var middleware = new MatchRouteToFlowApiMiddleware(flowConfiguration: flowConfiguration);
var context = new DefaultHttpContext();
context.Request.Method = "GET";
context.Request.Path = "/some/path";
context.Response.Body = new MemoryStream();

await middleware.InvokeAsync(context, (httpContext) => Task.FromResult(0));

context.Items.ContainsKey(nameof(Core.Request)).Should().BeTrue();
}

集成测试

[Fact]
public async Task Request_path_matches_an_api_route_and_method()
{
            //Arrange
   var response = await _httpClient.GetAsync("/some/route");

   response.StatusCode.Should().Be(500);
}

在执行单元测试时，我永远无法满足每个内部的要求，因为我在 HttpContext 上没有路由数据。

执行集成测试时，中间件按预期执行，但由于它没有终止，我无法验证

Answer 1

我意识到尝试终止我的中间件只是为了使用 xUnit 对其进行验证意味着我不会按原样测试我的系统，因此我更多地查看了我的单元测试设置。

我已经设法在 HttpContext 上获取路由数据。感觉很乱，但至少是一个起点。

 private static DefaultHttpContext DefaultHttpContextWithRoute(Fixture fixture)
 {
     var context = new DefaultHttpContext();
     var routeDictionary = new RouteValueDictionary
     {
         { "some","path" }
     };
     context.Features.Set<IRoutingFeature>(new RoutingFeature());
     context.Features.Get<IRoutingFeature>().RouteData = new RouteData(routeDictionary);

     var inline = fixture.Create<DefaultInlineConstraintResolver>();
     var route = new Route(new TestRouter(), "/some/path", inline);
     var httpMethodRouteConstraint = new HttpMethodRouteConstraint("GET");
     route.Constraints.Add("httpMethod", httpMethodRouteConstraint);
     context.Features.Get<IRoutingFeature>().RouteData.Routers.Add(route);
     context.Request.Method = "GET";
     context.Request.Path = "/some/path";
     context.Response.Body = new MemoryStream();
     return context;
}

private class TestRouter : IRouter
{
     public VirtualPathData GetVirtualPath(VirtualPathContext context)
     {
         throw new NotImplementedException();
     }

     public Task RouteAsync(RouteContext context)
     {
                throw new NotImplementedException();
     }
}

在每个单元测试中，我调用 DefaultHttpContext 并像这样调用我的中间件

DefaultHttpContext context = DefaultHttpContextWithRoute(fixture);

await middleware.InvokeAsync(context, (httpContext) => Task.FromResult(0));