public void IsValidWhen_EmployeeOrStudentAffiliation_IsNotEmpty()
 {
     var validator = new UpdateAffiliationValidator();
     var model = new UpdateAffiliationForm
     {
         EmployeeOrStudentAffiliation = EmployeeOrStudentAffiliate.Neither
     };
     var results = validator.Validate(model);
     var error = results.Errors.SingleOrDefault(e =>
         e.PropertyName == UpdateAffiliationForm.EmployeeOrStudentAffiliationPropertyName);
     error.ShouldBeNull();
 }
 public void IsInvalidWhen_EmployeeOrStudentAffiliation_IsNull()
 {
     var validator = new UpdateAffiliationValidator();
     var model = new UpdateAffiliationForm { EmployeeOrStudentAffiliation = null };
     var results = validator.Validate(model);
     results.IsValid.ShouldBeFalse();
     results.Errors.Count.ShouldBeInRange(1, int.MaxValue);
     var error = results.Errors.SingleOrDefault(e =>
         e.PropertyName == UpdateAffiliationForm.EmployeeOrStudentAffiliationPropertyName);
     error.ShouldNotBeNull();
     // ReSharper disable PossibleNullReferenceException
     error.ErrorMessage.ShouldEqual(
         UpdateAffiliationValidator.FailedBecauseEmployeeOrStudentAffiliationWasEmpty);
     // ReSharper restore PossibleNullReferenceException
 }