WebAPI核心flunt验证单位测试带有Xunit问题

Question

我正在使用ASP.NET Core WebAPI（6.0）。我正在使用流利的验证来验证。

public class Parameter
{
    public string? code { get; set; }
    public DateTime? TransactionDateFrom { get; set; }
}

public class ParameterValidator : AbstractValidator<Parameter>
{
    public ParameterValidator()
    {
        RuleFor(model => model.code)
            .Matches("^ABC.{10}$")
            .WithMessage("**barcode should be 13 char long and starts with ABC**");
        RuleFor(model => model.TransactionDateFrom.ToString())
            .Matches(@"^\d{4}\-(0[1-9]|1[012])\-(0[1-9]|[12][0-9]|3[01])$")
            .WithMessage("Date should be in the pattern of **YYYY-MM-DD**");
       
    }
}

我正在使用Xunit，Flunt验证编写单元测试。它不起作用

[Fact]
    public void Validate_TransactionDateFrom_InValid()
    {
        var param = new Parameter{ TransactionDateFrom = DateTime.Now };
        var result = _validator.TestValidate(param);
        result.ShouldHaveValidationErrorFor(parameter => parameter.TransactionDateFrom);
    }

    [Fact]
    public void Validate_code_Format_InValid()
    {
        var param = new Parameter{ code = "2791231231233" };
        var result = _validator.TestValidate(param);
        result.ShouldHaveValidationErrorFor(parameter => parameter.code);
    }