How to use TUnit.Aspire with custom environment variables

[toni-schmitt]

I need to pass custom environment variables to my AppHost so that my db uses Session lifetime and doesn't get reused.
I tried overriding ConfigureBuilder and setting variables withbuilder.Configuration["VAR"] = value but that did not seem to work. What is the intended way to set custom variables?
It is possible when overriding InitializeAsync and DisposeAsync but then I can't use the App property anymore, because there is not way to set it. Which makes the usage of AspireFixture a bit obsolete..

public class Fixture : AspireFixture<AppHost>
{
    protected override Task WaitForResourcesAsync(DistributedApplication app, CancellationToken cancellationToken) =>
        app.ResourceNotifications.WaitForResourceHealthyAsync("api", cancellationToken)
            .WithTimeout(TimeSpan.FromSeconds(60));

    public override async Task InitializeAsync()
    {
        // This will work, but now I can't use `base.App` anymore, as well as any other functionality from the base class..
        var appHost = await DistributedApplicationTestingBuilder.CreateAsync<AppHost>([
            "UseVolumes=false",
            "UsePostgresWithPersistentLifetime=false",
            "UsePostgresWithSessionLifetime=true"
        ]);
        ConfigureBuilder(appHost);
    }

    protected override void ConfigureBuilder(IDistributedApplicationTestingBuilder builder)
    {
        // These calls will not work, since `ConfigureBuilder` is called after DistributedApplicationTestingBuilder.CreateAsync
        builder.Configuration["UseVolumes"] = "false";
        builder.Configuration["UsePostgresWithPersistentLifetime"] = "false";
        builder.Configuration["UsePostgresWithSessionLifetime"] = "true";
        // ...
    }
}

[thomhurst]

@toni-schmitt I've just pushed an update that lets you set your own overrideable Args property

public class AppFixture : AspireFixture<Projects.MyAppHost>
{
    protected override string[] Args =>
    [
        "--UseVolumes=false",
        "--UsePostgresWithPersistentLifetime=false",
        "--UsePostgresWithSessionLifetime=true"
    ];
}

[toni-schmitt]

Thank you so much, that is exactly what I had in mind!