IntegrationTest.cs

public class IntegrationTest
{
    protected readonly HttpClient TestClient;
    private readonly IServiceProvider _serviceProvider;

    protected IntegrationTest()
    {
        var appFactory = new WebApplicationFactory<Startup>()
            .WithWebHostBuilder(builder =>
                {
                    builder.ConfigureServices(services =>
                    {
                        services.RemoveAll(typeof(DataContext));
                        services.AddDbContext<DataContext>(options => { options.UseInMemoryDatabase("TestDb"); });
                    });
                });

        _serviceProvider = appFactory.Services;
        TestClient = appFactory.CreateClient();
    }

    protected async Task AuthenticateAsync()
    {
        TestClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("bearer", await GetJwtAsync());
    }

    protected async Task<PostResponse> CreatePostAsync(CreatePostRequest request)
    {
        var response = await TestClient.PostAsJsonAsync(ApiRoutes.Posts.Create, request);
        return await response.Content.ReadAsAsync<PostResponse>();
    }

    private async Task<string> GetJwtAsync()
    {
        var response = await TestClient.PostAsJsonAsync(ApiRoutes.Identity.Register, new UserRegistrationRequest
        {
            Email = "[email protected]",
            Password = "SomePass1234!"
        });

        var registrationResponse = await response.Content.ReadAsAsync<AuthSuccessResponse>();
        return registrationResponse.Token;
    }
}