mgernand / Extensions.Logging.Mock

A unit-testing extension for verifying a logger mock.

Extensions.Logging.Mock

A unit-testing extension for verifying a logger mock.

Configuration

To configure the intrastructure you just have to call AddMock() on the ILoggingBuilder instance. when using AddLogging(). This will add a custom ILoggerProvider which will return the underlying instance of the configured Mock<ILogger> instance.

[TestFixture]
public class LoggerTests
{
	public Mock<ILogger> MockLogger { get; set; }
	public ILogger Logger { get; set; }
	public ILogger<TestClass> GenericLogger { get; set; }

	[SetUp]
	public void SetUp()
	{
		this.MockLogger = new Mock<ILogger>();

		IServiceCollection services = new ServiceCollection();

		services.AddLogging(builder =>
		{
			builder.SetMinimumLevel(LogLevel.Trace);
			builder.AddConsole();
			builder.AddMock(this.MockLogger);
		});

		IServiceProvider serviceProvider = services.BuildServiceProvider();

		ILoggerFactory loggerFactory = serviceProvider.GetRequiredService<ILoggerFactory>();
		this.Logger = loggerFactory.CreateLogger("TestLogger");
		this.GenericLogger = loggerFactory.CreateLogger<TestClass>();
	}
}

Usage

To verify that the desired log methods was called just verify the mock instance using VerifyLog().DebugWasCalled().

[Test]
public void ShouldVerifyDebugCalled()
{
	this.Logger.LogDebug("Log Message");
	this.MockLogger.VerifyLog().DebugWasCalled();
}

To verify that the desired log methods message output equals a desired values just verify the mock instance using VerifyLog().DebugWasCalled().MessageEquals("Log Message").

[Test]
public void ShouldVerifyDebugMessage()
{
	this.Logger.LogDebug("Log Message");
	this.MockLogger.VerifyLog().DebugWasCalled().MessageEquals("Log Message");
}

To verify that the desired log method was called a certain amount of times just verify the mock instance using VerifyLog().DebugWasCalled().Times(2).

[Test]
public void ShouldVerifyDebugCalledTimes()
{
	this.Logger.LogDebug("Log Message");
	this.Logger.LogDebug("Log Message");
	this.MockLogger.VerifyLog().DebugWasCalled().Times(2);
}