Maris.Logging.Testing 1.0.0

Maris.Logging.Testing

日本語版

This library provides Microsoft.Extensions.Logging.ILogger and Microsoft.Extensions.Logging.ILogger<TCategoryName> instances which can be used in xUnit tests. You can check the log output from test classes on Visual Studio Test Explorer. This library also provides the functionality to verify the log output within the test code by integrating Microsoft.Extensions.Logging.Testing.FakeLogger.

Install

Run the following command in Package Manager Console or Command Prompt to install Maris.Logging.Testing.

• Package Manager Console

Install-Package Maris.Logging.Testing

• Command Prompt

dotnet add package Maris.Logging.Testing

Usage

Suppose you have a class that requires an ILogger<TCategoryName> instance as shown below, and need to write xUnit test code for this class.

using Microsoft.Extensions.Logging;

namespace Maris;

public class TestTarget
{
    private readonly ILogger<TestTarget> Logger;

    public TestTarget(ILogger<TestTarget> logger)
        => this.Logger = logger;
    
    // ...
}

Follow these steps to use a test logger in the test code.

1. Install template for xUnit v3, and run dotnet new xunit3 to create a unit test project.
2. Install Maris.Logging.Testing in the unit test project.
3. In the test class, define a constructor with a Xunit.ITestOutputHelper parameter.
4. Create a Maris.Logging.Testing.Xunit.TestLoggerManager instance in the constructor, and store it in a field. Pass an ITestOutputHelper instance to the constructor of TestLoggerManager.
5. Call CreateLogger method of TestLoggerManager in the test method to create an ILogger or ILogger<TCategoryName> instance which can be passed to the test class.

using Maris.Logging.Testing.Xunit;
using Xunit;

namespace Maris.Tests;

public class TestClass1
{
    private readonly TestLoggerManager loggerManager;

    public TestClass1(ITestOutputHelper testOutputHelper)
        => this.loggerManager = new TestLoggerManager(testOutputHelper);

    [Fact]
    public void TestMethod()
    {
        // Creates ILogger<T> instance
        var logger = this.loggerManager.CreateLogger<TestTarget>();
        var target = new TestTarget(logger);

        // Do something...

        // TestLoggerManager.LogCollector exposes FakeLogger.Collector
        Assert.Equal(1, this.loggerManager.LogCollector.Count);  
        Assert.Equal("expectedCategory", this.loggerManager.LogCollector.LatestRecord.Category);
        Assert.Equal("expectedMessage", this.loggerManager.LogCollector.LatestRecord.Message);
    }
}

When testing Microsoft.Extensions.Hosting.IHost, AddTestLogging method can be used to register a test logger in the DI container. AddTestLogging method is defined in Microsoft.Extensions.DependencyInjection.TestLoggerServiceCollectionExtensions class. Here is an example of xUnit test code.

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Maris.Logging.Testing.Xunit;
using Xunit;

namespace Maris.Tests;

public class TestClass2
{
    private readonly TestLoggerManager loggerManager;

    public TestClass2(ITestOutputHelper testOutputHelper)
        => this.loggerManager = new TestLoggerManager(testOutputHelper);

    [Fact]
    public async Task TestMethod()
    {
        using var app = this.CreateHost();
        var cancellationToken = TestContext.Current.CancellationToken;
        await app.RunAsync(cancellationToken);
        
        // Do something...
    }

    private IHost CreateHost()
    {
        var builder = Host.CreateDefaultBuilder();
        builder.ConfigureServices((context, services) =>
        {
            // Register a test logger
            services.AddTestLogging(this.loggerManager);

            // Do something...            
        });

        return builder.Build();
    }
}

The log output during the test execution is displayed in Test Explorer as follows.

For more details, see Integration tests in ASP.NET Core.

Dependencies

• xunit.v3.extensibility.core

  The package used for developing xUnit v3 extensions. Maris.Logging.Testing only supports the unit test project with xUnit v3.

• Microsoft.Extensions.Diagnostics.Testing

  The library for testing log output.

License

Apache License Version 2.0