在 Xunit 集成测试中检索 ASP.NET Core 3.1 数据库上下文

Question

我一直在使用 Xunit 为使用数据库的 .NET Core 3.1 Web 应用程序创建集成测试。为了测试，我从Microsoft Documentation 切换到内存数据库。 CustomWebApplicationFactory 代码是：

public class CustomWebApplicationFactory<TStartup> : WebApplicationFactory<TStartup> where TStartup : class
        {
        protected override void ConfigureWebHost(IWebHostBuilder webHostBuilder)
            {
            webHostBuilder.ConfigureServices(services =>
                {
                    // Remove the app's database  registration.
                    var serviceDescriptor = services
                                                .SingleOrDefault(d => d.ServiceType == typeof(DbContextOptions<MyDbContext>));

                    if (serviceDescriptor != null)
                        {
                        services.Remove(serviceDescriptor);
                        }

                    // Add MyDbContext using an in-memory database for testing.
                    services.AddDbContext<MyDbContext>(options =>
                    {
                        options.UseInMemoryDatabase("InMemoryDbForTesting");
                    });

                    var servicesProvider = services.BuildServiceProvider();

                    // Create a scope to obtain a reference to the database context (MyDbContext).
                    using (var serviceScope = servicesProvider.CreateScope())
                        {
                        var scopedServices = serviceScope.ServiceProvider;
                        var db = scopedServices.GetRequiredService<MyDbContext>();
                        var logger = scopedServices.GetRequiredService<ILogger<CustomWebApplicationFactory<TStartup>>>();

                        db.Database.EnsureCreated();                                                                                                                                         // Ensure the database is created.

                        try
                            {
                            DatabaseSeeding.voidInitialiseCazIdentityProviderDatabase(db);                                                                                                                              // Seed the database with test data.
                            }
                        catch (Exception ex)
                            {
                            logger.LogError(ex, $"An error occurred seeding the database with data. Error: {ex.Message}");
                            }
                        }
                });
            }

我的基本页面测试在这种安排下运行良好，但我现在想检查内存数据库是否已被集成测试修改。无论发生什么，对数据库的引用都不会在 Xunit DI 容器中结束（如果存在这种情况）。我的测试类使用以下代码初始化：

    public class IdpUserServiceTests : IClassFixture<CustomWebApplicationFactory<Startup>>
    {
    private readonly CustomWebApplicationFactory<Startup> _webApplicationFactory;
    private readonly ITestOutputHelper _testOutput;
    private readonly HttpClient _httpClient;
    private readonly MyDbContext _myDbContext;

    public IdpUserServiceTests(CustomWebApplicationFactory<Startup> webApplicationFactory, MyDbContext myDbContext, ITestOutputHelper testOutput)
        {
        _webApplicationFactory = webApplicationFactory;
        _myDbContext = myDbContext;
        _testOutput = testOutput;
        _httpClient = _webApplicationFactory.CreateClient();
        }

    //Tests 

但在尝试运行测试时，我收到以下错误：

The following constructor parameters did not have matching fixture data: MyDbContext objMyDbContext

我正在寻找访问内存数据库的正确方法——显然不是通过构造函数注入。我已经接受了这个答案 - Access in memory dbcontext in integration test - 但事情似乎在 2.2 和 3.1 之间发生了变化。

Answer 1

事实证明，上面引用的 Access in memory dbcontext in integration test 答案对于 ASP.NET Core 3.1 并不完全正确。 scopeFactory 必须从不同的来源找到：

var scopeFactory = _webApplicationFactory.Services.GetService<IServiceScopeFactory>();

所以测试类现在看起来像：

public class ServiceTests : IClassFixture<CustomWebApplicationFactory<Startup>>
    {
    private readonly CustomWebApplicationFactory<Startup> _webApplicationFactory;
    private readonly ITestOutputHelper _testOutput;
    private readonly HttpClient _httpClient;

    public ServiceTests(CustomWebApplicationFactory<Startup> webApplicationFactory, ITestOutputHelper testOutput)
        {
        _webApplicationFactory = webApplicationFactory;
        _testOutput = testOutput;
        _httpClient = _webApplicationFactory.CreateClient();
        }

    [Fact]

    public async Task AServiceTest()
        {
        // Do some HTTP client stuff that alters the in-memory database

      var scopeFactory = _webApplicationFactory.Services.GetService<IServiceScopeFactory>();

        using(var scope = scopeFactory.CreateScope())
            {
            var myDataContext = scope.ServiceProvider.GetService<MyDataContext>();

            // Query the in-memory database
            }
        }
    }