Last edit of ConfigureServices, from Supermarket API

ConfigureServices.cs

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

    services.AddDbContext<AppDbContext>(options =>
    {
        options.UseInMemoryDatabase("supermarket-api-in-memory");
    });

    services.AddScoped<ICategoryRepository, CategoryRepository>();
    services.AddScoped<IProductRepository, ProductRepository>();
    services.AddScoped<IUnitOfWork, UnitOfWork>();

    services.AddScoped<ICategoryService, CategoryService>();
    services.AddScoped<IProductService, ProductService>();

    services.AddAutoMapper();
}