Csharp 如何处理ASP.NET Core中包含两个构造函数的控制器

我有一个API，我打算在其上通过xUnit和Moq进行单元测试.它实际上有一个构造函数，但我不得不添加另一个构造函数，以根据Visual Studio的建议进行特定的测试.它非常适合测试，但在try 通过Swagger测试API时，我遇到了另一个错误. "System.InvalidOperationException: Multiple constructors accepting all given argument types have been found in type 'Product.API.Controllers.ProductController'. There should only be one applicable constructor". 下面是控制器的内容

public class ProductController : ControllerBase
{
    private readonly IMediator _mediator;
    private readonly IConfiguration _configuration;
    private readonly UserManager<User> _userManager;
    private readonly SignInManager<User> _signInManager;
    private readonly ProductDbContext _productDbContext;
    private readonly IUserService _userService;

    public ProductController(IConfiguration configuration, UserManager<User> userManager, ProductDbContext productDbContext
        , SignInManager<User> signInManager, IUserService userService)
    {
        _configuration = configuration;
        _userManager = userManager;
        _productDbContext = productDbContext;
        _signInManager = signInManager;
        _userService = userService;
    }
    public ProductController(IMediator mediator)
    {
        _mediator = mediator;
    }
    [HttpGet]
    [AllowAnonymous]
    public async Task<IActionResult> GetAllProducts()
    {
        var products = await _mediator.Send(new GetAllProductsQuery());
        return Ok(products);
    }

以下是单元测试的代码

private readonly Mock<IMediator> _mediatorMock;
private readonly ProductController _controller;
public ProductControllerTest()
{
    _mediatorMock = new Mock<IMediator>();
    _controller = new ProductController(_mediatorMock.Object);
}
[Fact]
public async Task ProductController_GetAllProducts_ShouldReturnStatusCode200()
{
    //arrange
    var expected = new List<ProductModelDTO>();
    _mediatorMock.Setup(m=> m.Send(It.IsAny<GetAllProductsQuery>(), default(CancellationToken))).ReturnsAsync(expected);
    //act
    var result = await _controller.GetAllProducts();
    //assert
    var okResult = result as OkObjectResult;
    okResult?.StatusCode.Should().Be(200);
    okResult?.Value.Should().BeOfType<List<ProductModelDTO>>();
}

我遇到了一个可能的解决方案；向第二个构造函数添加一个[FromServices].但我也犯了同样的错误！