Managing lifecycle of HttpContext in integration tests when running in parallel

[dukesteen]

Hi Thom,
Love what you're doing with TUnit, but I'm running into some issues with managing the service scope of the HttpContext in my integration tests. I have the following IClassConstructor so I can use DI within my tests:

public sealed class DependencyInjectionClassConstructor : IClassConstructor, ITestEndEventReceiver, ILastTestInAssemblyEventReceiver
{
	internal static TestWebApplicationFactory WebApplication { get; } = CreateWebApplication().GetAwaiter().GetResult();

	private AsyncServiceScope _scope;

	public T Create<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] T>(
		ClassConstructorMetadata classConstructorMetadata
	)
		where T : class
	{
		_scope = WebApplication.Services.CreateAsyncScope();

		var httpContextAccessor = WebApplication.Services.GetRequiredService<IHttpContextAccessor>();
		httpContextAccessor.HttpContext = new DefaultHttpContext
		{
			RequestServices = _scope.ServiceProvider
		};

		return ActivatorUtilities.GetServiceOrCreateInstance<T>(_scope.ServiceProvider);
	}

	public async ValueTask OnTestEnd(TestContext testContext)
	{
		var httpContextAccessor = _scope.ServiceProvider.GetRequiredService<IHttpContextAccessor>();
		var a = httpContextAccessor.HttpContext;

		await _scope.DisposeAsync();
	}

	public async ValueTask IfLastTestInAssembly(AssemblyHookContext context, TestContext testContext)
	{
		await WebApplication.DisposeAsync();
	}

	private static async Task<TestWebApplicationFactory> CreateWebApplication()
	{
		var testContainer = new PostgreSqlBuilder().Build();
		await testContainer.StartAsync();

		return new TestWebApplicationFactory(testContainer.GetConnectionString());
	}

	[Before(Assembly)]
	public static async Task BeforeAssembly()
	{
		await MigrateApplication();
		await IntegrationTestContext.SetupTenant();
	}

	private static async Task MigrateApplication()
	{
		await using var serviceScope = WebApplication.Services.CreateAsyncScope();
		await using var dbContext = serviceScope.ServiceProvider.GetRequiredService<AppDbContext>();
		_ = await dbContext.Database.EnsureCreatedAsync();
		await dbContext.Database.MigrateAsync();
	}
}

In the Create<T> method I am setting the HttpContext on the IHttpContextAccessor to a new DefaultHttpContext so it can be used by things like asp.net identity (SignInManager<TUser> for example).

Now the issue lies in when these tests run in parallel, Create<T> seems to be called many times in a row to instantiate the DependencyInjectionClassConstructor for each test, which, in turn, sets the singleton IHttpContextAccessor to a new DefaultHttpContext many times, which means that tests now get an IHttpContextAccessor with a service scope that might already be disposed since it was set from a different test case.

I understand that having the static WebApplication field shares this state between test cases, and this is what I want, but I was wondering what my options are for having the correct HttpContext with the correct test case.

Two options I've thought of:

1. Having the WebApplication as a private field and not sharing it between test cases. In this case I could create the TestContainer once, and share that since it looks to be the most expensive operation when starting a new test
2. Not running tests in parallel, which would kind of suck to have all tests non-parallel for just a couple tests that require the HttpContext
3. Splitting out tests that require the HttpContext to be present into a seperate assembly and running those tests non-parallel

Looking forward to any ideas you might have.

[thomhurst]

So IHttpContextAccessor stores the contexts in an AsyncLocal field.

You're currently setting the context in the create method, which isn't in the tests async context yet, because it's needed earlier on the build the test.

Could you try subscribing to a test start event, and setting the context there? That method should have the tests async context so hopefully would set the async local properly.

[dukesteen]

Hi @thomhurst , thanks for the quick response.

I have tried setting the context in the OnTestStart event like so:

using System.Diagnostics.CodeAnalysis;
using Microsoft.AspNetCore.Http;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using Testcontainers.PostgreSql;
using Timespace.Api.Database;
using TUnit.Core.Interfaces;

namespace Timespace.IntegrationTests.Setup;

public sealed class DependencyInjectionClassConstructor : IClassConstructor, ITestEndEventReceiver, ITestStartEventReceiver, ILastTestInAssemblyEventReceiver
{
	internal static TestWebApplicationFactory WebApplication { get; } = CreateWebApplication().GetAwaiter().GetResult();

	private AsyncServiceScope _scope;

	public T Create<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] T>(
		ClassConstructorMetadata classConstructorMetadata
	)
		where T : class
	{
		_scope = WebApplication.Services.CreateAsyncScope();

		return ActivatorUtilities.GetServiceOrCreateInstance<T>(_scope.ServiceProvider);
	}

	public async ValueTask OnTestEnd(TestContext testContext)
	{
		var httpContextAccessor = _scope.ServiceProvider.GetRequiredService<IHttpContextAccessor>();
		var a = httpContextAccessor.HttpContext;

		await _scope.DisposeAsync();
	}

	public ValueTask OnTestStart(BeforeTestContext beforeTestContext)
	{
		var httpContextAccessor = WebApplication.Services.GetRequiredService<IHttpContextAccessor>();
		httpContextAccessor.HttpContext = new DefaultHttpContext
		{
			RequestServices = _scope.ServiceProvider
		};

		return ValueTask.CompletedTask;
	}

	public async ValueTask IfLastTestInAssembly(AssemblyHookContext context, TestContext testContext)
	{
		await WebApplication.DisposeAsync();
	}

	private static async Task<TestWebApplicationFactory> CreateWebApplication()
	{
		var testContainer = new PostgreSqlBuilder().Build();
		await testContainer.StartAsync();

		return new TestWebApplicationFactory(testContainer.GetConnectionString());
	}

	[Before(Assembly)]
	public static async Task BeforeAssembly()
	{
		await MigrateApplication();
		await IntegrationTestContext.SetupTenant();
	}

	private static async Task MigrateApplication()
	{
		await using var serviceScope = WebApplication.Services.CreateAsyncScope();
		await using var dbContext = serviceScope.ServiceProvider.GetRequiredService<AppDbContext>();
		_ = await dbContext.Database.EnsureCreatedAsync();
		await dbContext.Database.MigrateAsync();
	}
}

Same issue seems to occur.
Also happens when resolving the IHttpContextAccessor from the _scope like this
var httpContextAccessor = _scope.ServiceProvider.GetRequiredService<IHttpContextAccessor>();

[thomhurst]

Hmm... Could you create your own implementation of IHttpContextAccessor, with a new context passed to it on creation and register it as scoped?

Edit: just realised this would break if injected into singletons. Hmm...

[dukesteen]

Registering it as scoped does seem to do the trick!

I'll have to see what the implications of this are for the application itself.. The singleton thing is an issue yes, but I don't think I'm using IHttpContextAccessor in any singleton contexts

[dukesteen]

For any other people looking to do the same thing, you have 2 options:

Option 1: Create a custom implementation of IHttpContextAccessor and register it as scoped in your WebApplicationFactory<T>, then in your DependencyInjectionClassConstructor, inherit from ITestStartEventReceiver and add the following code

	public ValueTask OnTestStart(BeforeTestContext beforeTestContext)
	{
		var httpContextAccessor = _scope.ServiceProvider.GetRequiredService<IHttpContextAccessor>();
		httpContextAccessor.HttpContext ??= new DefaultHttpContext
		{
			RequestServices = _scope.ServiceProvider
		};

		return ValueTask.CompletedTask;
	}

This sets the HttpContext for the current scope with the correctly scoped services for the current test

Option 2: Use the default .AddHttpContextAccessor() in your test setup and set the HttpContext on the IHttpContextAccessor in the test itself, so it's in the same AsyncLocal scope

[ClassConstructor<DependencyInjectionClassConstructor>]
internal sealed class TestClass1(
	IHttpContextAccessor httpContextAccessor,
        IServiceProvider services
)
{
	[Test]
	public async Task Test1()
	{
	          httpContextAccessor.HttpContext ??= new DefaultHttpContext { RequestServices = services };
        }
}

Please feel free to comment if you've found any other (better) ways to do it.

[thomhurst]

To set them in each test, you could write a global hook like this:

[BeforeEvery(Test)]
    public static void SetHttpContext(TestContext context)
    {
        if (context.TestDetails.TestClassArguments.OfType<IHttpContextAccessor>().FirstOrDefault() is
            { } httpContextAccessor
            && context.TestDetails.TestClassArguments.OfType<IServiceProvider>().FirstOrDefault() is
                { } serviceProvider)
        {
            httpContextAccessor.HttpContext = new DefaultHttpContext()
            {
                RequestServices = serviceProvider
            };
        }
    }

[thomhurst]

I've just made some changes in 0.4.0 so this should work:

public sealed class DependencyInjectionClassConstructor : IClassConstructor, ITestStartEventReceiver, ITestEndEventReceiver, ILastTestInAssemblyEventReceiver
{
	internal static TestWebApplicationFactory WebApplication { get; } = CreateWebApplication().GetAwaiter().GetResult();

	private AsyncServiceScope _scope;

	public T Create<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] T>(
		ClassConstructorMetadata classConstructorMetadata
	)
		where T : class
	{
		_scope = WebApplication.Services.CreateAsyncScope();

		return ActivatorUtilities.GetServiceOrCreateInstance<T>(_scope.ServiceProvider);
	}

	public async ValueTask OnTestStart(BeforeTestContext testContext)
	{
		return Task.CompletedTask;
	}

        // Limitation currently with AsyncLocal - We have to set it in a synchronous method for it to propogate properly
	public void OnTestStartSynchronous(BeforeTestContext testContext)
	{
		var httpContextAccessor = WebApplication.Services.GetRequiredService<IHttpContextAccessor>();
		httpContextAccessor.HttpContext = new DefaultHttpContext
		{
			RequestServices = _scope.ServiceProvider
		};
	}

	public async ValueTask OnTestEnd(TestContext testContext)
	{
		var httpContextAccessor = _scope.ServiceProvider.GetRequiredService<IHttpContextAccessor>();
		var a = httpContextAccessor.HttpContext;

		await _scope.DisposeAsync();
	}

	public async ValueTask IfLastTestInAssembly(AssemblyHookContext context, TestContext testContext)
	{
		await WebApplication.DisposeAsync();
	}

	private static async Task<TestWebApplicationFactory> CreateWebApplication()
	{
		var testContainer = new PostgreSqlBuilder().Build();
		await testContainer.StartAsync();

		return new TestWebApplicationFactory(testContainer.GetConnectionString());
	}

	[Before(Assembly)]
	public static async Task BeforeAssembly()
	{
		await MigrateApplication();
		await IntegrationTestContext.SetupTenant();
	}

	private static async Task MigrateApplication()
	{
		await using var serviceScope = WebApplication.Services.CreateAsyncScope();
		await using var dbContext = serviceScope.ServiceProvider.GetRequiredService<AppDbContext>();
		_ = await dbContext.Database.EnsureCreatedAsync();
		await dbContext.Database.MigrateAsync();
	}
}

You should be able to do this with the default HttpContextAccessor, and not need to register your own scoped version.