Testing the MetadataType Module

Question

I am working on an ASP.NET MVC 2 application and I am testing my view models.

[TestMethod] public void EmailNeedsToBeSet() { var pvm = new ProfileViewModel {Email = ""}; var validationResults = new ValidationResults(); var result = Validator.TryValidateObject(pvm, new ValidationContext(pvm, null, null), validationResults, true); Assert.IsFalse(result); Assert.IsTrue(validationResults.ContainsField<ProfileViewModel>(m => m.Email)); } 

An email property is required and this test method works great

My question is: how can I check the MetaData class, as in the test before? verification results are always true. Or is it not possible?

An example of my MetaData class:

 [MetadataType(typeof (UserMetaData))] public partial class User { public class UserMetaData { [Required(ErrorMessageResourceName = "Required", ErrorMessageResourceType = typeof (ValidationStrings))] [LocalizedDisplayName("LoginName", NameResourceType = typeof (Fields))] [StringLength(64)] public string Login { get; set; } } } 

Answer 1

Here is how I unit test this type of code:

  [TestMethod] public void IsValid_Returns_ValidationResult_Errors_When_Properties_With_Meta_Data_Are_Not_Valid() { var sut = new User { Login = "too long!!!" }; var actual = sut.IsValid(); Assert.IsNotNull(actual); Assert.AreEqual(1, actual.Count); Assert.AreEqual(1, actual[0].MemberNames.Count()); var firstValidationError = actual[0]; Assert.AreEqual("Login", firstValidationError.MemberNames.First()); Assert.AreEqual("The field Login must be a string with a maximum length of 4.", firstValidationError.ErrorMessage); } [TestMethod] public void IsValid_Returns_Empty_List_Of_Errors_When_Properties_With_Meta_Data_Are_Valid() { var sut = new User { Login = "abcd" }; var actual = sut.IsValid(); Assert.IsNotNull(actual); Assert.AreEqual(0, actual.Count); } [MetadataType(typeof(UserMetaData))] public partial class User : BaseEntity { public string Login { get; set; } public class UserMetaData { [Required] [StringLength(4)] public string Login { get; set; } } } public abstract class BaseEntity { protected BaseEntity() { RegisterMetadata(); } private void RegisterMetadata() { var currentType = GetType(); var metadataType = GetMetadataType(); if (metadataType == null) return; var descriptorProvider = new AssociatedMetadataTypeTypeDescriptionProvider(currentType, metadataType); TypeDescriptor.AddProviderTransparent(descriptorProvider, currentType); } private Type GetMetadataType() { var attribute = Attribute.GetCustomAttributes(this.GetType()).ToList().Find(t => t is MetadataTypeAttribute); return (attribute != null) ? ((MetadataTypeAttribute)attribute).MetadataClassType : null; } public virtual List<ValidationResult> IsValid() { var validationErrors = new List<ValidationResult>(); var context = new ValidationContext(this, null, null); Validator.TryValidateObject(this, context, validationErrors, true); return validationErrors; } }