c# - 如何使用 WebApplicationFactory 播种测试数据？

Question

我正在为 .NET Core 3.1 Web API 进行集成测试。我关注了这篇文章Painless Integration Testing with ASP.NET Core Web API .这是我的 CustomWebApplicationFactory:

public class CustomWebApplicationFactory<TStartup> : WebApplicationFactory<TStartup> where TStartup : class
{
    protected override void ConfigureWebHost(IWebHostBuilder builder)
    {
        builder.ConfigureServices(services =>
        {
            var descriptor = services.SingleOrDefault(d => d.ServiceType == typeof(DbContextOptions<TestDbContext>));
            if (descriptor != null)
            {
                services.Remove(descriptor);
            }

            services.AddDbContext<TestDbContext>(options =>
            {
                options.UseInMemoryDatabase("InMemoryTestDb");
            });

            var sp = services.BuildServiceProvider();

            using (var scope = sp.CreateScope())
            {
                var scopedServices = scope.ServiceProvider;
                var db = scopedServices.GetRequiredService<TestDbContext>();
                var logger = scopedServices.GetRequiredService<ILogger<CustomWebApplicationFactory<TStartup>>>();

                db.Database.EnsureCreated();

                try
                {
                    Console.WriteLine("Seeding...");

                    var players = Utilities.GetTestPlayers(); // Returns 3 test players
                    db.Players.RemoveRange(db.Players); // Clear the table
                    db.Players.AddRange(players); // Add 3 test players
                    db.SaveChanges();

                    Console.WriteLine($"Players seeded: { db.Players.Count() }");
                }
                catch (Exception ex)
                {
                    logger.LogError(ex, "An error occurred seeding the " + "database with test messages. Error: {Message}", ex.Message);
                }
            }
        });
    }
}

这些是我的测试:对于每个 Controller，我在单独的类中创建了测试。在测试类的构造函数中，我创建了一个 Client。像这样的 TestController(我在 API 中总共有 4 个 Controller ):

public class BaseControllerTest : IClassFixture<CustomWebApplicationFactory<Startup>>
{
    protected HttpClient Client { get; }

    public BaseControllerTest(CustomWebApplicationFactory<Startup> factory)
    {
        Client = factory.CreateClient();
    }
}

public class TestControllerShould : BaseControllerTest
{
    public TestControllerShould(CustomWebApplicationFactory<Startup> factory)
        : base(factory)
    {
        Console.WriteLine("TestControllerShould");
    }

    [Fact]
    public async Task GetHelloWorld()
    {
        var request = new HttpRequestMessage(new HttpMethod("GET"), "/test/");
        var response = await Client.SendAsync(request);

        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
        var content = await response.Content.ReadAsStringAsync();
        Assert.Equal("Hello World!", content);
        Assert.False(response.Headers.Contains("Server"), "Should not contain server header");
    }
} 

我的问题是:

正如您在 CustomWebApplicationFactory 中看到的那样，我在播种时记录日志，这是我看到的日志:

Seeding...
Seeding...
Seeding...
Seeding...
Players seeded: 12
Players seeded: 12
Players seeded: 12
Players seeded: 12

我总共有 4 个 Controller ，我只为 3 个玩家播种。为什么我看到 12？我不明白。看起来行 db.Players.AddRange(players); 在任何 db.SaveChanges(); 之前被调用了 4 次(对于每个 Controller 测试类)。然后 db.SaveChanges(); 被连续调用了 4 次。为什么？

我的问题是:这是为什么？以及如何在集成测试中正确播种测试数据？

(如果不是通过回答，任何对一篇好文章的引用都将非常感谢)

谢谢

Answer 1

它为每个 Controller 调用 ConfigureServices。所以在这里你可以做一件事在调用 db.Database.EnsureCreated() 之前调用 db.Database.EnsureDeleted()。它将为每个 Controller 重新初始化内存数据库。