Discovery of hooks from shared assemblies

[danielmackay]

Hi there,

I have a solution with several test projects that I would like to share common setup code. This common setup code contains hooks to run code before any of the tests:

Project structure:

Shared test code:

public static class Testing
{
    private static readonly SqlServerTestDatabase _database = new();
    private static CustomWebApplicationFactory _factory = null!;
    private static IServiceScopeFactory _scopeFactory = null!;

    [Before(Assembly)]
    public static async Task GlobalSetup()
    {
        await _database.InitializeAsync();
        _factory = new CustomWebApplicationFactory(_database.GetConnection());
        _scopeFactory = _factory.Services.GetRequiredService<IServiceScopeFactory>();
    }
    
    // <snip>
}

However, I've noticed GlobalSetup() will only get called if this class exists in the same test project the tests are contained in. I would like to be able to have this common setup code in one place, and re-used by all test projects, but currently this does not work.

1. Is there anyway to get TUnit to find and execute this setup code in a shared common for all test projects?

Thanks in advance.

[thomhurst]

This kinda relies on how the .NET runtime loads assemblies. If the assembly is loaded before test discovery, then hooks will be loaded and registered. Thing is with .NET, assemblies generally aren't loaded until they're first referenced.

You can use a [Before(TestDiscovery)] hook and call a type from your assembly containing the hooks. Even just doing a console write line on a type from that assembly should load it in and fix your problem

[danielmackay]

@thomhurst i had a quick play and it didn't work. I'll spend a bit more time on it tonight.

Thanks so much for your help and speedy reply. 🙏

[danielmackay]

@thomhurst - no it didn't work.

I've created a small sample repo: https://github.com/danielmackay/dotnet-tunit-shared-setup

Any other suggestions?

[thomhurst]

Ah sorry I should've noticed this earlier - you're using [Before(Assembly)] - That only affects the assembly it's defined in!

There's [BeforeEvery(Assembly)] that'll run once each time before each assembly's tests start

    [BeforeEvery(Assembly)]
    public static void GlobalSetup(AssemblyHookContext context)
    {
        _initialized = true;
    }

[thomhurst]

Alternatively if you only want it to run once, and you'll invoke multiple test sessions, you can just use [Before(TestSession)]

[danielmackay]

It worked! 🥳

I've updated my repo above, plus the project I was originally working on, and all tests are passing as expected.

I managed to get the setup working, both with [BeforeEvery(Assembly)] and [Before(TestSession)].

I might do a blog post on this in the near future. 😄

Thanks again for your help @thomhurst!

[danielmackay]

BTW - When working on this I got a slightly confusing error:

I realise this is because a parameter ofAssemblyHookContext is needed instead.

1. Are you able to update the TUnit error to be more specific in this case?

[thomhurst]

I noticed that myself too. I'll try and sort it soon :)

[thomhurst]

Fixed :)

[danielmackay]

Nice! 😁