Asp.net core 2.1 unit test automapper?

Question

Error message

Message: System.InvalidOperationException : Mapper not initialized. Call Initialize with appropriate configuration. If you are trying to use mapper instances through a container or otherwise, make sure you do not have any calls to the static Mapper.Map methods, and if you're using ProjectTo or UseAsDataSource extension methods, make sure you pass in the appropriate IConfigurationProvider instance.

Application project

Define a mapping profile (ApplicationMappingProfile.cs)

public class ApplicationMappingProfile : Profile
{
    public ApplicationMappingProfile()
    {
        CreateMap<User, UserListDto>();
        CreateMap<Permission, PermissionListDto>();
        // add auto mapper mapping configurations here
    }
}

Register automapper services (ApplicationServiceCollectionExtensions.cs)

public static class ApplicationServiceCollectionExtensions
{
    public static IServiceCollection AddKodkodApplication(this IServiceCollection services)
    {
        services.AddAutoMapper();

        //todo: add conventional registrar
        services.AddTransient<IUserAppService, UserAppService>();
        services.AddTransient<IPermissionAppService, PermissionAppService>();

        return services;
    }
}

Unit test project

Create a test server to run Startup.cs (ApiTestBase.cs)

public class ApiTestBase : TestBase
{
    protected static HttpClient Client;

    public ApiTestBase()
    {
        //if this is true, Automapper is throwing exception
        ServiceCollectionExtensions.UseStaticRegistration = false;

        Client = GetTestServer();
    }

    private static HttpClient GetTestServer()
    {
        if (Client != null)
        {
            return Client;
        }

        var server = new TestServer(
            new WebHostBuilder()
                .UseStartup<Startup>()
                .ConfigureAppConfiguration(config =>
                {
                    config.SetBasePath(Path.GetFullPath(@"../../.."));
                    config.AddJsonFile("appsettings.json", false);
                })
        );

        return server.CreateClient();
    }
}

And test (AccountTests.cs).

public class AccountTests : ApiTestBase
{
    [Fact]
    public async Task TestAuthorizedAccessAsync()
    {
        var responseLogin = await LoginAsTestUserAsync();
        var responseContent = await responseLogin.Content.ReadAsAsync<OkObjectResult>();
        var responseJson = JObject.Parse(responseContent.Value.ToString());
        var token = (string)responseJson["token"];

        var requestMessage = new HttpRequestMessage(HttpMethod.Get, "/api/test/GetUsers/");
        requestMessage.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
        var responseGetUsers = await Client.SendAsync(requestMessage);
        Assert.Equal(HttpStatusCode.OK, responseGetUsers.StatusCode);

        var users = await responseGetUsers.Content.ReadAsAsync<PagedList<UserListDto>>();
        Assert.True(users.Items.Count > 0);
    }
}

This test method calling /api/test/GetUsers/ method that is using an appservice (PermissionAppService.cs). This app service return a dto that is mapped from entity with using automapper. So exception is occuring here.

When I removed following line:

ServiceCollectionExtensions.UseStaticRegistration = false;

Then I am getting following error:

Message: System.InvalidOperationException : Mapper already initialized. You must call Initialize once per application domain/process.

This error occuring, because there are more than one classes that are inherited from ApiTestBase class. If I run only TestAuthorizedAccessAsync method, It runs with no issue.

The question can be a bit complicated, sorry for this :) feel free to ask where you don't understand.

PROJECT SOURCE

Edit

It works when I run web api project that uses appServices

Edit2

if I added following lines to TestBase constructor, only one test is failing and others passed.

public TestBase()
{
    lock (ThisLock)
    {
        Mapper.Reset();
        Client = GetTestServer();
    }

....

Have you tried using the overload services.AddAutoMapper(typeof(Startup).Assembly);? — Sander Declerck
– Sander Declerck, Commented Jun 6, 2018 at 9:56
@SanderDeclerck, services.AddAutoMapper is in a seperate project. But yes I tried it(moved services.AddAutoMapper to web project) — AliRıza Adıyahşi
– AliRıza Adıyahşi, Commented Jun 6, 2018 at 10:00
First of all, don't use the static mapping API. AM has an instance-based mapping API that's much easier to use, esp. when using dependency injection. — Gert Arnold
– Gert Arnold, Commented Jun 20, 2018 at 7:49
ServiceCollectionExtensions.UseStaticRegistration = false; should be right before services.AddAutoMapper();, otherwise it won't have effect. — Ivan Stoev
– Ivan Stoev, Commented Jun 20, 2018 at 8:14
@AliRızaAdıyahşi Consider self-answering your question then! Cheers! :) — BartoszKP
– BartoszKP, Commented Jun 22, 2018 at 9:14

AliRıza Adıyahşi · Accepted Answer · 2018-06-27 06:47:25Z

Disable automapper static registration and initialize it to pass as parameter to app service

TestBase.cs

public class TestBase
{
    private static Dictionary<string, string> _testUserFormData;

    protected readonly IMapper Mapper;
    protected readonly KodkodDbContext KodkodInMemoryContext;
    protected readonly ClaimsPrincipal ContextUser;
    protected readonly HttpClient Client;
    protected async Task<HttpResponseMessage> LoginAsTestUserAsync()
    {
        return await Client.PostAsync("/api/account/login",
            _testUserFormData.ToStringContent(Encoding.UTF8, "application/json"));
    }

    public TestBase()
    {
        // disable automapper static registration
        ServiceCollectionExtensions.UseStaticRegistration = false;

        // Initialize mapper
        Mapper = new Mapper(
            new MapperConfiguration(
                configure => { configure.AddProfile<ApplicationMappingProfile>(); }
            )
        );
        Client = GetTestServer();

        _testUserFormData = new Dictionary<string, string>
        {
            {"email", "[email protected]"},
            {"username", "testuser"},
            {"password", "123qwe"}
        };

        KodkodInMemoryContext = GetInitializedDbContext();
        ContextUser = GetContextUser();
    }
...

Pass mapper as paramater to app service

UserApplicationServiceTests.cs

public class UserApplicationServiceTests : ApplicationTestBase
{
    private readonly IUserAppService _userAppService;

    public UserApplicationServiceTests()
    {
        var userRepository = new Repository<User>(KodkodInMemoryContext);
        _userAppService = new UserAppService(userRepository, Mapper);
    }
...

CodeNotFound · Accepted Answer · 2018-06-06 09:58:59Z

1

TO avoid this error:

Message: System.InvalidOperationException : Mapper already initialized. You must call Initialize once per application domain/process.

You need to call Mapper.Reset() before executing each test:

The static Mapper.Initialize is intended to be called only once. To reset the static mapping configuration

Reset should not be used in production code. It is intended to support testing scenarios only.

You can call it at the beginning of the unit test but I recommend to do it in your unit test class default constrcutor like below:

public AccountTests()
{
    Mapper.Reset();
}

answered Jun 6, 2018 at 9:58

CodeNotFound

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7 Comments

AliRıza Adıyahşi Over a year ago

No luck! There are a lot of same advices. I tried all of them. I think there is a design problem with my code. BTW, even if your suggestion works, it's a workaround.

AliRıza Adıyahşi Over a year ago

It doesn't make sense to use a base test class.

CodeNotFound Over a year ago

@AliRızaAdıyahşi I don't say anything about base test class. What do you mean by that?

CodeNotFound Over a year ago

@AliRızaAdıyahşi This what is proposed by the documentation If it didn't work you might look how you write your test or even better, like you said on your first comment, redesign your code.

AliRıza Adıyahşi Over a year ago

You are right, I should redesign code, but many of users in github say that Mapper.Reset(); is not working solution as mine. Thanks for your effort to advice.

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