Verifying FluentValidation in tests using xUnit/TestHelper

Assuming a class with a custom validator, similar to the following:

1public record FeedbackCreateRequest
2{
3    public string Url { get; set; } = null!;
4
5    public FeedbackResponse Response { get; set; } // An enum consisting of 3 options
6
7    public string? Context { get; set; }
8
9    public class Validator : AbstractValidator<FeedbackCreateRequest>
10    {
11        public Validator()
12        {
13            RuleFor(request => request.Url)
14                .NotEmpty();
15
16            RuleFor(request => request.Response)
17                .IsInEnum();
18
19            RuleFor(request => request.Context)
20                .MaximumLength(250);
21        }
22    }
23}

You can easily verify the request object is being validated as you expect by instantiating the validator and calling ShouldHaveValidationErrorFor:

1[Fact]
2public async Task FeedbackCreateRequestValidator_InvalidFields_IncludesRelevantErrors()
3{
4    // Arrange
5    var validator = new FeedbackCreateRequest.Validator();
6
7    var request = new FeedbackCreateRequest
8    {
9        Response = (FeedbackResponse)5,
10        Context = new string('a', 251),
11    };
12
13    // Act
14    var result = await validator.TestValidateAsync(request);
15
16    // Assert
17    Assert.Equal(3, result.Errors.Count);
18    result.ShouldHaveValidationErrorFor(feedback => feedback.Url);
19    result.ShouldHaveValidationErrorFor(feedback => feedback.Response);
20    result.ShouldHaveValidationErrorFor(feedback => feedback.Context);
21}

Verifying FluentValidation in unit tests

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