Use WebApplicationFactory to test CoreWCF endpoints with AutoFac DI - integration-testing

Question

I have a CoreWCF project with Autofac DI and I want to create some Integration Tests using a custom WebApplicationfactory.
I have used the custom WebApplicationFactory code for Autofac suggested here
https://github.com/autofac/Autofac/issues/1207 by Alistair Evans
This works fine for WebApi endpoints but it does not work for my CoreWCF endpoints.
What I found was that the Microsoft.AspNetCore.TestHost.TestServer that is created does not define the Features property with any IServerAddressesFeature. This causes a problem when the CoreWCF.ServiceObjectModel ApplyConfiguration is executed.
I have got around this by using reflection to set the Features property in the CreateServiceProvider method of the CustomServiceProviderFactory as shown below but does anybody know if there is a better way around this.
/// Enables in-memory integration testing for CoreWCF (outside-in testing via <see cref="HttpClient"/>).
///
/// Use these tests to exercise the entire HTTP stack, rather than create in-process ServiceModel channels.
///
/// <see href="https://learn.microsoft.com/en-us/aspnet/core/test/integration-tests?view=aspnetcore-3.1"/>
/// <seealso href="https://learn.microsoft.com/en-us/aspnet/core/test/integration-tests?view=aspnetcore-2.1"/>
/// </summary>
/// <typeparam name="TStartup"></typeparam>
public class WcfWebApplicationFactory<TStartup> : WebApplicationFactory<TStartup> where TStartup : class
{
private ILifetimeScope _container;
protected override void ConfigureWebHost(IWebHostBuilder builder)
{
builder.ConfigureTestContainer<ContainerBuilder>(container =>
{
container.RegisterBuildCallback(BuildCallback);
});
builder.ConfigureTestServices(services =>
{
});
}
private void BuildCallback(ILifetimeScope obj)
{
_container = obj;
}
protected override IHost CreateHost(IHostBuilder builder)
{
builder.UseServiceProviderFactory(new CustomServiceProviderFactory(ClientOptions.BaseAddress.ToString()));
return base.CreateHost(builder);
}
protected override IHostBuilder? CreateHostBuilder()
{
return base.CreateHostBuilder();
}
}
/// <summary>
/// Based upon https://github.com/dotnet/aspnetcore/issues/14907#issuecomment-620750841 - only necessary because of an issue in ASP.NET Core
/// </summary>
public class CustomServiceProviderFactory : IServiceProviderFactory<ContainerBuilder>
{
private readonly string _testServerBaseAddress;
private AutofacServiceProviderFactory _wrapped;
private IServiceCollection _services;
public CustomServiceProviderFactory(string testServerBaseAddress)
{
_testServerBaseAddress = testServerBaseAddress;
_wrapped = new AutofacServiceProviderFactory();
}
public ContainerBuilder CreateBuilder(IServiceCollection services)
{
// Store the services for later.
_services = services;
return _wrapped.CreateBuilder(services);
}
public IServiceProvider CreateServiceProvider(ContainerBuilder containerBuilder)
{
var sp = _services.BuildServiceProvider();
#pragma warning disable CS0612 // Type or member is obsolete
var filters = sp.GetRequiredService<IEnumerable<IStartupConfigureContainerFilter<ContainerBuilder>>>();
#pragma warning restore CS0612 // Type or member is obsolete
foreach (var filter in filters)
{
filter.ConfigureContainer(b => { })(containerBuilder);
}
var serviceProvider = _wrapped.CreateServiceProvider(containerBuilder);
// The CoreWCF.ServiceObjectModel ApplyConfiguration expects there to be at least one IServerAddressesFeature
// This is normally present for the Kestrel webserver but for the TestServer in the Microsoft.AspNetCore.TestHost namespace does not seem to populate it
// Had to use Refelction to set this since the Set method causes a containerBuilder Build operation
var addresses = new ServerAddressesFeature();
addresses.Addresses.Add(_testServerBaseAddress);
var features = new FeatureCollection();
features.Set<IServerAddressesFeature>(addresses);
var testServer = serviceProvider.GetRequiredService<IServer>();
var field = typeof(TestServer).GetField("<Features>k__BackingField", BindingFlags.Instance | BindingFlags.NonPublic);
field.SetValue(testServer, features);
return serviceProvider;
}
}
}

Answer 1

I have found some clue in https://stackoverflow.com/a/48547597/3299257
Specifically in the announcement
Hosting no longer adds default server address when no address is explicitly configured
The WebHost will no longer add the default server address of http://localhost:5000 to the IServerAddressesFeature when none is specified. The configuration of the default server address will now be a responsibility of the server.
Addresses specified in IServerAddressesFeature are intended to be used by servers as a fallback when no explicit address is specified directly.
Adding feature was discussed here https://github.com/dotnet/aspnetcore/issues/5931 and came to conclusion that it won't be implemented in TestServer.
In my test scenario I do not use full WebApplicationFactory, but rather directly utilize TestServer so I could make a simpler soultion:
var addresses = new ServerAddressesFeature();
addresses.Addresses.Add("http://localhost");
var features = new FeatureCollection();
features.Set<IServerAddressesFeature>(addresses);
return new TestServer(builder, features);
In your scenario:
(sorry, this is not verified), you could use WebApplicationFactory.WithWebHostBuilder and then, invoke .UseTestServer constructing your own TestServer and providing feature collection in the second argument.
factory.WithWebHostBuilder(builder => {
var addresses = new ServerAddressesFeature();
addresses.Addresses.Add("http://localhost");
var features = new FeatureCollection();
features.Set<IServerAddressesFeature>(addresses);
builder.UseTestServer(new TestServer(builder, features));
});