AgentSkillsCN

test-integration-api

端到端API测试——使用WebApplicationFactory进行完整的请求管道测试、创建认证客户端、模拟HTTP依赖（Flurl）、进行类型安全的客户端测试，并对路由进行验证。这些测试适用于控制器、端点以及API行为的验证。关键词：API测试、E2E测试、WebApplicationFactory、HTTP模拟、Flurl、端点测试、控制器测试、认证、集成测试、DTT、技能、测试、集成

SKILL.md
--- frontmatter
name: test-integration-api
description: End-to-end API testing - WebApplicationFactory for full request pipeline testing, authenticated client creation, HTTP dependency mocking (Flurl), typed client testing, and route validation. Use for testing controllers, endpoints, and API behavior. Keywords: api-testing, e2e-testing, webapplicationfactory, http-mocking, flurl, endpoint-testing, controller-testing, authentication, integration-testing, dtt, skills, test, integration

API Integration Testing

End-to-end API testing using WebApplicationFactory and HTTP interaction mocking.

Core Patterns

Authenticated Client

CreateClientAsync automatically handles:

  1. •App startup
  2. •DB migrations & external dependencies binding
  3. •Test user authentication
csharp
[Theory]
[DataInline]
public async Task Api_Should_Return_Data(DrnTestContext context, ITestOutputHelper outputHelper)
{
    var client = await context.ApplicationContext.CreateClientAsync<SampleProgram>(outputHelper);
    
    var endpoint = Get.Endpoint.Sample.WeatherForecast.Get.RoutePattern;
    var forecasts = await client.GetFromJsonAsync<WeatherForecast[]>(endpoint);
    
    forecasts.Should().NotBeEmpty();
}

Mocking HTTP Dependencies

Mock downstream services (Typed Clients, InternalRequest, ExternalRequest) to test proxy behavior and failure modes.

[!TIP] Typed clients (like INexusClient, IXyzApiClient) typically use Flurl under the hood. Mock them by targeting their URL patterns.

Typed HTTP Clients (e.g., INexusClient)

Most typed clients wrap IInternalRequest (for internal mesh services) or IExternalRequest. The pattern for testing them is identical: mock the underlying URL pattern.

csharp
[Theory]
[DataInline]
public async Task Should_Proxy_Nexus_Response(DrnTestContext context, ITestOutputHelper outputHelper)
{
    var client = await context.ApplicationContext.CreateClientAsync<SampleProgram>(outputHelper);
    var appSettings = context.GetRequiredService<IAppSettings>();
    
    // Pattern: {ServiceAddress}/{Path}
    // IInternalRequest automatically handles the base URL from settings
    // Example: Mocking a Nexus service call
    var nexusUrl = $"*{appSettings.NexusAppSettings.NexusAddress}/WeatherForecast";
    var mockData = new[] { new WeatherForecast { Summary = "Mocked Nexus Data" } };
    
    // Mock the specific call
    context.FlurlHttpTest.ForCallsTo(nexusUrl).RespondWithJson(mockData);
    
    // Call the application endpoint that triggers the Client
    var endpoint = Get.Endpoint.Sample.WeatherForecast.GetNexusWeatherForecasts.RoutePattern;
    var result = await client.GetFromJsonAsync<WeatherForecast[]>(endpoint);
    
    result.Should().BeEquivalentTo(mockData);
}

External Request (IExternalRequest)

For direct external calls (e.g., 3rd party APIs).

csharp
[Theory]
[DataInline]
public async Task Should_Mock_External_Api(DrnTestContext context, ITestOutputHelper outputHelper)
{
    var client = await context.ApplicationContext.CreateClientAsync<SampleProgram>(outputHelper);
    
    context.FlurlHttpTest
        .ForCallsTo("https://api.thirdparty.com/*")
        .RespondWith("OK", 200);
        
    // ... triggering action
}

Simulating Failures

csharp
[Theory]
[DataInline]
public async Task Should_Handle_API_Failure(DrnTestContext context, ITestOutputHelper output)
{
    var client = await context.ApplicationContext.CreateClientAsync<SampleProgram>(output);
    
    // Simulate server error
    context.FlurlHttpTest.ForCallsTo("*").RespondWith(status: 500);
    
    var response = await client.GetAsync("/api/external-dependent");
    response.StatusCode.Should().Be(HttpStatusCode.BadGateway);
}

Route Validation

Validate route patterns without starting the full app server if only route data is needed.

csharp
[Theory]
[DataInline]
public async Task EndPointFor_Should_Return_Endpoint_Address(DrnTestContext context)
{
    await context.ApplicationContext.CreateApplicationAndBindDependenciesAsync<SampleProgram>();
    
    var endpoint = Get.Endpoint.User.Identity.RegisterController.ConfirmEmail;
    endpoint.RoutePattern.Should().NotBeNull();
}

### Test Isolation
`ApplicationContext` automatically sets the following flags to ensure your tests run in isolation and do not attempt to launch external dependencies (which would collide with test containers):
1. **Not in Test**: `TestEnvironment.DrnTestContextEnabled` is set to `true`.
2. **Temporary**: `AppSettings.DevelopmentSettings.TemporaryApplication` is set to `true`.

This ensures that logic like `LaunchExternalDependenciesAsync` knows it is running in a test context and skips starting local development containers.

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