如何在核心MVC中对RazorViewEngine选项进行单元测试 ASP.NET

Question

在从ConfigureServices调用的扩展方法中，我将EmbeddedFileProvider的实例添加到RazorViewEngineOptions。我想测试它是否已添加，但我找不到如何获取RazorViewEngineOptions实例。

这在应用程序运行时有效：

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc()
                  .SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
    services.AddMyServices(Configuration);
}

public static IServiceCollection AddMyServices(this IServiceCollection services, IConfiguration configuration)
{
    services.Configure<RazorViewEngineOptions>(options => 
    {
        options.FileProviders.Add(new EmbeddedFileProvider(typeof(MyClass).Assembly, "My.Namespace"));
    });
    return services;
}

但是我该如何测试呢？这里抛出了一个NullReferenceException：

[Fact]
public void MyTest()
{
    var services = new ServiceCollection();
    var serviceProvider = services.BuildServiceProvider();
    MyServicesBuilder.AddMyServices(services, new Mock<IConfiguration>().Object);
    var razorOptions = serviceProvider.GetService<IOptions<RazorViewEngineOptions>>();
    Assert.Equal(1, razorOptions.Value.FileProviders.Where(x => x.GetType() == typeof(EmbeddedFileProvider)).Count());
}

我尝试添加services.AddMvc()或services.AddSingleton<RazorViewEngineOptions>().

我也试过打电话给services.GetRequiredService<RazorViewEngineOptions>()但这会抛出System.InvalidOperationException : No service for type 'Microsoft.Extensions.Options.IOptions'1[Microsoft.AspNetCore.Mvc.Razor.RazorViewEngineOptions

我也尝试过要求RazorViewEngineOptions而不是IOptions<RazorViewEngineOptions>。

Answer 1

在构建提供程序后添加到服务集合的任何内容都不会被提供程序知道。

将所需的所有内容添加到服务集合中，然后才生成提供程序以执行断言

例如

[Fact]
public void MyTest() {
    //Arrange
    var services = new ServiceCollection();
    services.AddOptions();
    IConfiguration config = new ConfigurationBuilder()
        // Call additional providers here as needed.
        //...
        .Build();
    //Act
    MyServicesBuilder.AddMyServices(services, config);
    //OR
    //services.AddMyServices(config);
    //Assert
    var serviceProvider = services.BuildServiceProvider();
    var razorOptions = serviceProvider.GetService<IOptions<RazorViewEngineOptions>>();
    Assert.NotNull(razorOptions);
    Assert.Equal(1, razorOptions.Value.FileProviders.Where(x => x.GetType() == typeof(EmbeddedFileProvider)).Count());
}