Microsoft.Testing.Extensions.Logging

Microsoft.Testing.Extensions.Logging

Microsoft.Testing.Extensions.Logging is an extension for Microsoft.Testing.Platform that bridges the platform's logging pipeline with Microsoft.Extensions.Logging, so diagnostic messages produced by the platform and its extensions can flow through any Microsoft.Extensions.Logging provider — Console, Debug, Serilog, Application Insights, OpenTelemetry, custom sinks, and more.

Microsoft.Testing.Platform is open source. You can find Microsoft.Testing.Extensions.Logging code in the microsoft/testfx GitHub repository.

Install the package

dotnet add package Microsoft.Testing.Extensions.Logging

You will typically also add a Microsoft.Extensions.Logging provider package, e.g.:

dotnet add package Microsoft.Extensions.Logging.Console

Usage

using Microsoft.Extensions.Logging;
using Microsoft.Testing.Extensions;
using Microsoft.Testing.Platform.Builder;

ITestApplicationBuilder builder = await TestApplication.CreateBuilderAsync(args);

builder.AddMicrosoftExtensionsLogging(logging =>
{
    logging.AddConsole();
    logging.AddDebug();
});

using ITestApplication app = await builder.BuildAsync();
return await app.RunAsync();

About

This package extends Microsoft.Testing.Platform with:

• Bridge to Microsoft.Extensions.Logging: any MTP diagnostic log message is forwarded to the configured Microsoft.Extensions.Logging providers in addition to the platform's built-in --diagnostic file logger.
• Reuse existing logging stacks: plug Serilog, OpenTelemetry logs, Application Insights, or your own custom ILoggerProvider into the testing platform without writing a custom MTP logger provider.

The bridge maps Microsoft.Testing.Platform.Logging.LogLevel to Microsoft.Extensions.Logging.LogLevel, forwards the same state, exception, and formatter through to Microsoft.Extensions.Logging.ILogger.Log, and respects per-category filter rules defined in the ILoggingBuilder.

Notes and limitations

• EventId is not propagated. Microsoft.Testing.Platform's ILogger has no notion of EventId; every forwarded log entry is written with EventId.None. Consumers that rely on EventId-based filtering downstream of the bridge will not see distinct IDs.
• MTP does not create logging scopes. The bridge does not synthesize or translate BeginScope operations because Microsoft.Testing.Platform's logging contract has no scope API. Ambient scopes created by the caller may still be observed by its providers, but they are not controlled by MTP.
• Structured state is forwarded, not reconstructed. The original state and formatter are passed unchanged to the Microsoft.Extensions logger. Providers can retain structure that was present in the original MTP log entry, but the bridge cannot recover message-template properties from an entry that was already produced as a formatted string.
• Per-category filters can only narrow, never widen. The bridge initializes the ILoggingBuilder with the platform's effective diagnostic level, and the platform itself filters messages before they reach any provider. Setting a more verbose minimum level inside configure has no effect.
• No-op when --diagnostic is off. When the platform's effective LogLevel is None (the default), the configure delegate is not invoked and no Microsoft.Extensions.Logging.LoggerFactory is created, so expensive sinks (network, file, gRPC) are not initialized for runs that will never emit a log.
• LogAsync is forwarded synchronously. Microsoft.Extensions.Logging has no async logging API; ILogger.LogAsync calls ILogger.Log directly and returns Task.CompletedTask. The bridge does not block on asynchronous work, but a provider that performs blocking I/O still blocks the calling thread.
• Owned vs. caller-owned factories. The Action<ILoggingBuilder> overload creates and disposes its own ILoggerFactory. The ILoggerFactory overload never disposes the caller-supplied instance.
• Registration is process-local. A supplied logger factory cannot cross a process boundary. Separately launched test host or controller processes must register their own bridge if their diagnostic logs need to reach the same external system.

Documentation

For comprehensive documentation, see https://aka.ms/testingplatform.

Feedback & contributing

Microsoft.Testing.Platform is an open source project. Provide feedback or report issues in the microsoft/testfx GitHub repository.