public void IsSubdomain_PassingInvalidArgumentsReturnErrors() { var mock = new FakeObject { Subdomain = FakeTypes.ReferenceTypes.ClassTypes.String_New(), }; var validator = new FakeObjectValidator(); validator.RuleFor(_ => _.Subdomain) .IsSubdomain() .IsSubdomain(nameof(FakeObject.Subdomain) + FakeObject.FIELD_NAME); // Validate var result = validator.Validate(mock); var messages = result.ToString(); Assert.IsFalse(result.IsValid); Assert.IsTrue(result.Errors.Count == 2); Assert.IsFalse(string.IsNullOrWhiteSpace(messages)); Assert.IsTrue(messages.Contains(Messages.Subdomain(mock.Subdomain, nameof(FakeObject.Subdomain)))); Assert.IsTrue(messages.Contains(Messages.Subdomain(mock.Subdomain, nameof(FakeObject.Subdomain) + FakeObject.FIELD_NAME))); }