C3D.Extensions.Logging.Xunit 0.2.2

C3D.Extensions.Logging.Xunit

An implementation of Microsoft.Extensions.Logging Loggers wrapping xunit output types. This allows you to capture logging output when using dotnet test etc. It can be injected into services under test, or used as a provider in DI.

It supports some minor configuration which can be added via the normal configuration sources, such as appsettings.json, usersecrets etc.

Configuration

{
	"Logging": {
		"Xunit": {
			"MinLevel": "Trace",
			"UseOffset": true,
			"LogLevel": {
				"Default": "Trace"
			}
		}
	}
}

Usage

Dependency Injection

services
	.AddSingleton(output)
	.AddLogging(logging => logging
		.ClearProviders()
		.SetMinimumLevel(LogLevel.Debug)
		.AddXunit());

Here output can be either ITestOutputHelper or IMessageSink, depending on whether you are using this from a unit test, or a class fixture.

Alternatively, you can explicitly add the output, and/or setup the logging configuration inside the AddXunit extension method.

logging
	.AddXunit(output, config=>{
	});

N.B. This will add the output object as a singleton to the ILoggingBuilder services.

Direct injection

private readonly ITestOutputHelper output;

ILogger<ClassUnderTest> log = output.CreateLogger<ClassUnderTest>();

\\ Assuming that the constuctor of ClassUnderTest takes an ILogger or ILogger<ClassUnderTest>
var sut = new ClassUnderTest(log);

\\ perform tests with logging...

Here the ILogger creation line might replace something like

ILogger<ClassUnderTest> log = Microsoft.Extensions.Logging.Abstractions.NullLoggerFactory.Instance.CreateLogger<ClassUnderTest>();

Factory

You can also create a LoggerFactory if you need to using something like

private readonly ITestOutputHelper output;

var loggerFactory = LoggerFactory.Create(builder => builder.AddXunit(output));

Fixtures

The same mechanisms used in tests based on injecting ITestOutputHelper into the test class, can be used in fixtures. However, in fixtures you inject IMessageSink. The same extension methods are available for both interfaces.

Utilities

As you may want to check the logged output for content in your tests (either for something existing or not existing), there are 2 utility classes provided.

• LoggingMessageSink which implements IMessageSink
• LoggingTestOutputHelper which implements ITestOutputHelper

These both have a ClearMessages function (which may be required in a fixture to ensure output from one test does not affect another), and a Messages property.

Examples of how to use these can be found in the unit tests at CZEMacLeod/C3D.Extensions.Logging.