Could not set ASP.NET Core 3.1 environment string within an xUnit Integration Test

Question

I'd like to setup integration test for my ASP.NET Core 3.1 using the code below and have not been able to get the environment string correctly and even with UseEnvironment("integration-test") method, I still end up with null when I call Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT") from within the Startup class. I tried getting the environment string from IWebHostEnvironment but from there I get "Development".

/// <summary>
/// Application test fixture to generate the test host.
/// </summary>
/// <typeparam name="TStartup">The type of the startup.</typeparam>
/// <seealso cref="WebApplicationFactory{TStartup}" />
public class AppTestFixture<TStartup> : WebApplicationFactory<TStartup>
    where TStartup : class
{
    /// <summary>
    /// The configuration.
    /// </summary>
    private Action<IServiceCollection> _configuration;

    /// <summary>
    /// Call this as a way to override container registration for integration testing.
    /// </summary>
    /// <param name="configuration">The configuration.</param>
    public void ConfigureTestServices(Action<IServiceCollection> configuration)
    {
        this._configuration = configuration;
    }

    /// <summary>
    /// Creates a <see cref="T:Microsoft.AspNetCore.Hosting.IWebHostBuilder" /> used to set up <see cref="T:Microsoft.AspNetCore.TestHost.TestServer" />.
    /// </summary>
    /// <returns>
    /// A <see cref="T:Microsoft.AspNetCore.Hosting.IWebHostBuilder" /> instance.
    /// </returns>
    /// <remarks>
    /// The default implementation of this method looks for a <c>public static IWebHostBuilder CreateWebHostBuilder(string[] args)</c>
    /// method defined on the entry point of the assembly of <typeparamref name="TEntryPoint" /> and invokes it passing an empty string
    /// array as arguments.
    /// </remarks>
    protected override IWebHostBuilder CreateWebHostBuilder()
    {
        var builder = WebHost.CreateDefaultBuilder()
            .UseEnvironment("integration-test")
            .UseStartup<TStartup>();

        if (this._configuration != null)
        {
            builder.ConfigureTestServices(this._configuration);
        }

        return builder;
    }
}

Answer 1

I had to use the Environment's static method and set the environment accordingly. Like what I did here on my .NET 6 microservice app

https://github.com/secret-agent-B/devkit-dotnet-core/blob/master/src/apps/core/sdk/test/Devkit.Test/AppTestFixture.cs