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

问题

I'm trying to write unit test case for the BackgroundService Worker.cs. I have read Stack Overflow Question

But still I get the error that

"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);
}

回答1:

I do not see where you add IConfiguration to the service collection. You build one in the constructor but do not add it to the service collection in the test.

[Fact]
public async Task ExecuteAsync_Test() {

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

    //...

来源：https://stackoverflow.com/questions/60387013/while-unit-testing-a-net-core-3-1-background-service-unable-to-resolve-iconfig