ILogger / ILoggerFactory implementation to use in XUnit tests for pushing log messages into the test output

TestOutputLogger.cs

using System.Text;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Xunit.Abstractions;

namespace MyGists;

public class TestOutputLoggerFactory : ILoggerFactory
{
    private readonly ITestOutputHelper _testOutputHelper;

    public TestOutputLoggerFactory(ITestOutputHelper testOutputHelper)
    {
        _testOutputHelper = testOutputHelper;
    }

    /// <summary>
    /// Registers a logger that outputs to the unit test output, to easily display logging messages in unit test results.
    /// </summary>
    public static void Register(IServiceCollection serviceCollection, ITestOutputHelper testOutputHelper)
        => serviceCollection.AddTransient<ILoggerFactory>(provider => new TestOutputLoggerFactory(testOutputHelper));

    public void Dispose() { }

    public ILogger CreateLogger(string categoryName) => TestOutputLogger.CreateLogger(_testOutputHelper, categoryName);

    public void AddProvider(ILoggerProvider provider)
    {
        throw new NotImplementedException();
    }
}

public class TestOutputLogger : ILogger
{
    private readonly ITestOutputHelper _testOutputHelper;
    private readonly LoggerExternalScopeProvider _scopeProvider;
    private readonly string _categoryName;

    public TestOutputLogger(ITestOutputHelper testOutputHelper, LoggerExternalScopeProvider scopeProvider, string categoryName)
    {
        _testOutputHelper = testOutputHelper;
        _scopeProvider = scopeProvider;
        _categoryName = categoryName;
    }

    public static ILogger CreateLogger(ITestOutputHelper testOutputHelper, string categoryName) => new TestOutputLogger(testOutputHelper, new LoggerExternalScopeProvider(), categoryName);

    public bool IsEnabled(LogLevel logLevel) => true;

    public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception?, string> formatter)
    {
        var sb = new StringBuilder();
        sb.Append(GetLogLevelString(logLevel))
            .Append(" [").Append(_categoryName).Append("] ")
            .Append(formatter(state, exception));

        if (exception != null)
        {
            sb.Append('\n').Append(exception);
        }

        _scopeProvider.ForEachScope((scope, s) =>
        {
            s.Append("\n => ");
            s.Append(scope);
        }, sb);

        _testOutputHelper.WriteLine(sb.ToString());
    }

    private static string GetLogLevelString(LogLevel logLevel) =>
        logLevel switch
        {
            LogLevel.Trace => "TRACE",
            LogLevel.Debug => "DEBUG",
            LogLevel.Information => "INFO ",
            LogLevel.Warning => "WARN ",
            LogLevel.Error => "ERROR",
            LogLevel.Critical => "CRIT ",
            _ => throw new ArgumentOutOfRangeException(nameof(logLevel))
        };

    public IDisposable? BeginScope<TState>(TState state) where TState : notnull => _scopeProvider.Push(state);
}