单元测试自动映射器以返回角色中的用户数

Question

I would like to unit test this Controller . It returns the name of the role and the count of users that belong to that role :

    [HttpGet]
    [EnableQuery]
    public IEnumerable<RoleDto> Get()
    {
        var roles = dbContext.Roles.ToList();

        return roles.Select(r =>
        {
            var dto = mapper.Map<RoleDto>(r);
            dto.UserCount = dbContext.UserRoles.Count(x => x.RoleId == r.Id); 
            return dto;
        }).ToList();
    }

And here is my test - The DTO is always null and later throws an exception . I am unable to map this properly.

It is a simple unit test that creates a user , creates roles and add the user to those roles .

It then checks if a user has been added to that role .

    [Test]
    public async Task Get_Should_Return_List_OfRoles()
    {
        TestSetup();
        var mapperMock = new Mock<IMapper>();
        IdentityRole role = null;

        mapperMock.Setup(u => u.Map<RoleDto>(It.IsAny<IdentityRole>()))
            .Callback<object>(inputargs => role = inputargs as IdentityRole);
        var roleManagerWrapperMock = new Mock<IRoleManagerWrapper>();

        var admin = new IntentUser
        {
            UserName = "Administrator2",
            Email = "admin2@intent2.app",
            EmailConfirmed = true,
            IsEnabled = true,
            IsSystemUser = true
        };

        var adminRole = new IdentityRole()
        {
            Name = "Admin"
        };

        var managerRole = new IdentityRole()
        {
            Name = "Manager"
        };
        ApplicationDbContext.Users.Add(admin);
        ApplicationDbContext.Roles.Add(managerRole);
        ApplicationDbContext.Roles.Add(adminRole);

        ApplicationDbContext.SaveChanges();

        var adminRoleAdded = new IdentityUserRole<string>()
        {
            RoleId = adminRole.Id,
            UserId = admin.Id
        };

        var managerRoleAdded = new IdentityUserRole<string>()
        {
            RoleId = managerRole.Id,
            UserId = admin.Id
        };

        ApplicationDbContext.UserRoles.Add(adminRoleAdded);
        ApplicationDbContext.UserRoles.Add(managerRoleAdded);
        ApplicationDbContext.SaveChanges();

            var sut = new RolesController(roleManagerWrapperMock.Object, ApplicationDbContext, mapperMock.Object);
            var result = sut.Get();
            foreach (var roleDto in result)
            {
                Assert.AreEqual(roleDto.UserCount, 1);
            }
    }

    protected void TestSetup(string databaseName = null)
    {
        if (databaseName == null)
        {
            databaseName = GetTestName();
        }

        TestCleanup();
        ServiceProvider = new ServiceCollection()
            .AddEntityFrameworkInMemoryDatabase()
            .BuildServiceProvider();

        dbContextOptions = new DbContextOptionsBuilder<ApplicationDbContext>()
            .UseInMemoryDatabase(databaseName)
            .UseInternalServiceProvider(ServiceProvider)
            .Options;

        ApplicationDbContext = new ApplicationDbContext(dbContextOptions);
    }

Answer 1

As mentioned in the comments, you can use an actual mapper instead of trying to mock it.

//...

//Configure mapping just for this test but something like this
//should be in accessible from your composition root and called here.
var config = new MapperConfiguration(cfg => {
    cfg.CreateMap<RoleDto, IdentityRole>();
    cfg.CreateMap<IdentityRole, RoleDto>();
});

IMapper mapper = config.CreateMapper();
// or
//IMapper mapper = new Mapper(config);

//...

Reference Automapper: Getting Started Guide