如何为每个测试创建单独的内存数据库？

Question

我正在 .NET Core 3.0 上使用 xunit 编写测试，内存数据库有问题。我需要为每个测试创建一个单独的数据库，但现在我创建了一个导致问题的数据库，但我不知道如何为每个测试创建一个新数据库。

public class AccountAdminTest : IClassFixture<CustomWebApplicationFactory<Startup>>
{
    private readonly HttpClient _client;
    private IServiceScopeFactory scopeFactory;
    private readonly CustomWebApplicationFactory<Startup> _factory;
    private ApplicationDbContext _context;

    public AccountAdminTest(CustomWebApplicationFactory<Startup> factory)
    {
        _factory = factory;
        _client = _factory.CreateClient(new WebApplicationFactoryClientOptions
        {
            AllowAutoRedirect = true,
            BaseAddress = new Uri("https://localhost:44444")
        });

        scopeFactory = _factory.Services.GetService<IServiceScopeFactory>();
        var scope = scopeFactory.CreateScope();
        _context = scope.ServiceProvider.GetService<ApplicationDbContext>();
    }
}

public class CustomWebApplicationFactory<TStartup> : WebApplicationFactory<TStartup> where TStartup : class
{
    protected override void ConfigureWebHost(IWebHostBuilder builder)
    {
        builder.ConfigureTestServices(services =>
        {
            var descriptor = services.SingleOrDefault(
                d => d.ServiceType ==
                    typeof(DbContextOptions<ApplicationDbContext>));

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

            services.AddDbContext<ApplicationDbContext>((options, context) =>
            {
                context.UseInMemoryDatabase("IdentityDatabase");
            });
        });
    }
}

现在看起来像这样，但还是不行。当我在 AddDbContext 上更改生命周期时，它不会改变任何东西。

public class AccountAdminTest : IDisposable
{
    public AccountAdminTest(ITestOutputHelper output)
    {
        this.output = output;

        _factory = new CustomWebApplicationFactory<Startup>();

        _client = _factory.CreateClient(new WebApplicationFactoryClientOptions
        {
            AllowAutoRedirect = true,
            BaseAddress = new Uri("https://localhost:44444")
        });

        scopeFactory = _factory.Services.GetService<IServiceScopeFactory>();
        _scope = scopeFactory.CreateScope();
        _context = _scope.ServiceProvider.GetService<ApplicationDbContext>();


        var _user = User.getAppAdmin();
        _context.Add(_user);
        _context.SaveChanges(); //Here i got error on secound test. It says "An item with the same key has already been added"
    }

    public void Dispose()
    {
        _scope.Dispose();
        _factory.Dispose();
        _context.Dispose();
        _client.Dispose();
    }

使用 Guid 作为数据库名称时无法获取令牌。它说 username/password 无效。我使用 IdentityServer 进行身份验证

public async Task<string> GetAccessToken(string userName, string password, string clientId, string scope)
        {
            var disco = await _client.GetDiscoveryDocumentAsync("https://localhost:44444");
            if (!String.IsNullOrEmpty(disco.Error))
            {
                throw new Exception(disco.Error);
            }
            var response = await _client.RequestPasswordTokenAsync(new PasswordTokenRequest
            {
                Address = disco.TokenEndpoint,
                ClientId = clientId,
                Scope = scope,
                UserName = userName,
                Password = password,
            });
            return response.AccessToken;
        }

Answer 1

编辑： 您必须为每个测试指定一个唯一的名称运行避免与 slightly mentioned here and and 共享同一个 InMemory 数据库。

尽管如此，下面切换到 "Constructor and Dispose" 的建议仍然适用。

IClassFixture 不是正确使用的工具，the documentation says:

When to use: when you want to create a single test context and share it among all the tests in the class, and have it cleaned up after all the tests in the class have finished.

在你的情况下，你必须使用“Constructor and Dispose”，文档说：

When to use: when you want a clean test context for every test (sharing the setup and cleanup code, without sharing the object instance).

因此您的测试将是：

public class AccountAdminTest
{
    private readonly HttpClient _client;
    private IServiceScopeFactory scopeFactory;
    private readonly CustomWebApplicationFactory<Startup> _factory;
    private ApplicationDbContext _context;

    public AccountAdminTest(CustomWebApplicationFactory<Startup> factory)
    {
        //
        _factory = new CustomWebApplicationFactory<Startup>();

        _client = _factory.CreateClient(new WebApplicationFactoryClientOptions
        {
            AllowAutoRedirect = true,
            BaseAddress = new Uri("https://localhost:44444")
        });

        scopeFactory = _factory.Services.GetService<IServiceScopeFactory>();
        _scope = scopeFactory.CreateScope();
        _context = scope.ServiceProvider.GetService<ApplicationDbContext>();
    }

    //Tests...

    public void Dispose() {

        _scope.Dispose();
        _factory.Dispose();

        //Dispose and cleanup anything else...
    }

}

或者，您可以为 DbContext using this overload of .AddDbContext

指定 ServiceLifetime.Transient 的生命周期

Answer 2

您只需更改此处的代码：

services.AddDbContext<ApplicationDbContext>((options, context) =>
{
    context.UseInMemoryDatabase("IdentityDatabase");
});

而不是常量值 "IdentityDatabase"，使用 Guid.NewGuid().ToString():

context.UseInMemoryDatabase(Guid.NewGuid().ToString());

然后，每次获取上下文时，都会使用新的内存数据库。

如何为每个测试创建单独的内存数据库？

How to create separate in memory database for each test?

c#

testing

xunit

asp.net-core