Mediatr and service collection to test handler within controller

test-mediatr-and-cqrs-handler

public async Task ShouldReturnListOfSelfies()
        {
            // ARRANGE
            var expectedList = new List<Selfie>()
            {
                new Selfie() { Wookie = new Wookie() },
                new Selfie() { Wookie = new Wookie() }
            };
            var repositoryMock = new Mock<ISelfieRepository>();

            repositoryMock.Setup(item => item.GetAll(It.IsAny<int>())).Returns(expectedList);

            var services = new ServiceCollection();

            var serviceConfig = new MediatRServiceConfiguration();
            ServiceRegistrar.AddRequiredServices(services, serviceConfig);

            services.AddScoped<IRequestHandler<SelectAllSelfiesQuery, List<SelfieResumeDto>>, SelectAllSelfiesHandler>();
            //services.AddMediatR(typeof(SelectAllSelfiesHandler).GetType().Assembly);
            services.AddSingleton(typeof(ISelfieRepository), repositoryMock.Object);
            var provider = services.BuildServiceProvider();

            var mediator = provider.GetRequiredService<IMediator>();
            var service = provider.GetRequiredService<ISelfieRepository>();


            //mediatorMock.Setup(item => item.Send(It.IsAny<int>(), CancellationToken.None)).Returns(Task.FromResult<object>(expectedList));

            var controller = new SelfiesController(mediator, repositoryMock.Object, new Mock<IWebHostEnvironment>().Object);

            // ACT
            var result = await controller.GetAll();

            // ASSERT
            Assert.NotNull(result);
            Assert.IsType<OkObjectResult>(result);

            OkObjectResult okResult = result as OkObjectResult;

            var resultObject = okResult.Value;

            Assert.NotNull(resultObject);
            Assert.IsType<List<SelfieResumeDto>>(resultObject);

            List<SelfieResumeDto> list = okResult.Value as List<SelfieResumeDto>;
            Assert.True(list.Count == expectedList.Count);
        }