对 .Net core 3.1 后台服务进行单元测试时，无法解析 IConfiguration

Question

我正在尝试为 BackgroundService Worker.cs 编写单元测试用例。我已阅读

但我仍然收到

的错误

"Unable to resolve service for type 'Microsoft.Extensions.Configuration.IConfiguration' while attempting to activate 'AutoClueArchiver.Worker'.

public WorkerTests()
{
    _config = new ConfigurationBuilder()
            .AddJsonFile("appsettings.json", true, true)
            .AddJsonFile("appsettings.Development.json", true, true)
            .AddJsonFile("appsettings.local.json", true, true)
            .AddJsonFile("\\charon.cmiprog.com\devinet\Configuration\" + "ApiEndpoints.json", false, true)
            .AddJsonFile("ApiEndpoints.local.json", true, true)
            .AddJsonFile("\\charon.cmiprog.com\devinet\Configuration\" + "Kafka.json", false, true)
            .AddEnvironmentVariables().Build();
         _mockedKafkaTopicConsumerManager =new Mock<IKafkaTopicConsumerManager>();
         _mockedMessageProcessor=new Mock<IMessageProcessingCapable>();
}

[Fact]
public async Task ExecuteAsync_Test()
{            
     IServiceCollection services=new ServiceCollection();
     services.AddSingleton<IConfigEntriesClientService, ConfigEntriesClientServiceInjectable>();
     services.AddSingleton(typeof(IProducer), s => new KafkaProducer(s.GetRequiredService<IProducer<string, string>>(), s.GetRequiredService<IConfiguration>().GetValue<string>("Shared:Kafka:TopicSuffix")));
     services.AddSingleton(typeof(IProducer<string, string>), c => new ProducerBuilder<string, string>(KafkaConfigs(c)).Build());
     services.AddHttpClient();
     services.AddScoped<IPolicyApiClient, PolicyApiClient>();
     services.AddTransient<IFilterMessages, MessageFilter>();
     services.AddTransient<IArchiveAutoClues, Archiver>();
     services.AddTransient<IFileSystem, FileSystem>();
     services.AddTransient<ISaveDocument, DocumentManager>();
     services.AddTransient<IKafkaTopicConsumerManager, KafkaTopicConsumerManager>();
     services.AddTransient<IMessageProcessingCapable, ConsumerInitializer>();
     services.AddTransient<Consumer>();
     services.AddTransient<IExceptionPublisher, ExceptionPublisher>();
     services.AddTransient<IHttpContextAccessor, HttpContextAccessor>();
     services.AddScoped(sp => new HttpClientHandler { AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate });
     services.AddHttpClient<IBaseApiClient, BaseApiClient>().ConfigurePrimaryHttpMessageHandler(
     sp => new HttpClientHandler { AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate }
            );

     var worker=services.AddHostedService<Worker>();
     var serviceProvider=services.BuildServiceProvider();
     var backgroundService = serviceProvider.GetService<IHostedService>() as Worker;
     await backgroundService?.StartAsync(CancellationToken.None);
     await Task.Delay(1000);
     await backgroundService?.StopAsync(CancellationToken.None);
     //await backgroundService.ExecuteAsync(new CancellationToken()); 
     //Any way to access ExecuteAsync here since I get protection level error as 
     //ExecuteAsync is protected
     _mockedKafkaTopicConsumerManager.Verify(c=>c.StartConsumption
     (It.IsAny<CancellationToken>(), 
     _mockedMessageProcessor.Object,
                It.IsAny<string>(),
                It.IsAny<string>(),
                It.IsAny<List<string>>(),
                It.IsAny<string>(),
                It.IsAny<int>()),Times.Once);
}

Answer 1

我没有看到您将 IConfiguration 添加到服务集合的位置。您在构造函数中构建一个但不将其添加到测试中的服务集合。

[Fact]
public async Task ExecuteAsync_Test() {

    IServiceCollection services = new ServiceCollection();
    services.AddSingleton<IConfiguration>(_config);

    //...

Answer 2

如果您使用 xUnit dependecy nuget，获取 IConfiguration 的最佳方法是：

在 Stratup.cs

 public void ConfigureHost(IHostBuilder hostBuilder) =>
        hostBuilder.ConfigureAppConfiguration(lb => lb.AddJsonFile("appsettings.json", false, true))
            .UseServiceProviderFactory(new AutofacServiceProviderFactory());

然后在你的构造函数中测试 class:

readonly IConfiguration _configuration;
public WorkerTestUnit(IConfiguration configuration)
    =>
        _configuration = configuration;

终于在你的测试中：

[Fact]
    public async Task ExecuteAsync_Test()
    {
.....
services.AddSingleton<IConfiguration>(_configuration);
....
}

对 .Net core 3.1 后台服务进行单元测试时，无法解析 IConfiguration

While Unit Testing a .Net core 3.1 Background Service, unable to resolve IConfiguration

c#

unit-testing

.net-core

background-service