Testable code using Dynamic Data Store

There is some talk about how testing using EPiServer is a hassle. And it is for many reasons. There are exceptions though, and Dynamic Data Store is one of them. In contrast to EPiServer.DataFactory for example, which is a sealed class, both DynamicDataStoreFactory and DynamicDataStore are abstract classes. This is good news from a testing perspective since we can override their behavior. Good work team!

The example I´m gonna show is from the EPiSocial plugin I´ve been working on, which uses DDS. This is from the CommentRepository.

Setup

First some setup changes. Instead of using DynamicDataStoreFactory.Instance to get the store:

        1: public DynamicDataStoreCommentRepository()

       2: {

       3:     this.commentStore = DynamicDataStoreFactory.Instance.GetStore(typeof(PageComment));

       4: }

We can instead take a dependency to the abstract class DynamicDataStoreFactory:

       1: public DynamicDataStoreCommentRepository(DynamicDataStoreFactory dynamicDataStoreFactory)

       2: {

       3:     this.commentStore = dynamicDataStoreFactory.GetStore(typeof(PageComment));

       4: }

With this small change we´ll be able to test the code in the CommentRepository.

Let´s use the GetLatestComments method as the scenario for this:

       1: public IEnumerable<PageComment> GetLatestComments(int count, string pageLanguage)

       2: {

       3:     return this.commentStore.Items<PageComment>()

       4:         .Where(c => c.PageLanguage == pageLanguage)

       5:         .OrderByDescending(c => c.Created)                

       6:         .Take(count);

       7: }

Testing

To test that method we have to setup a fake data store to test against. I did this using Moq. Let´s say that we want to test that the method returns only pages in the language that we provide. It could look something like this:

       1: [Test]

       2: public void Given_a_store_with_comments_for_multiple_pages_when_getting_latest_comments_then_only_comments_for_provided_page_language_is_returned()

       3: {

       4:     // Arrange

       5:     var pageCommentList = new List<PageComment>();

       6:     pageCommentList.Add(new PageComment { PageId = 1, PageLanguage = "sv" });            

       7:     pageCommentList.Add(new PageComment { PageId = 2, PageLanguage = "en" });

       8:  

       9:     IOrderedQueryable<PageComment> queryableItemList = new EnumerableQuery<PageComment>(pageCommentList );

      10:     var dataStoreFactoryMock = new Mock<DynamicDataStoreFactory>();

      11:     var dataStoreMock = new Mock<DynamicDataStore>(null);

      12:  

      13:     dataStoreFactoryMock

      14:         .Setup(x => x.GetStore(typeof(PageComment)))

      15:         .Returns(dataStoreMock.Object);

      16:  

      17:     dataStoreMock

      18:          .Setup(x => x.Items<PageComment>())

      19:          .Returns(queryableItemList);

      20:  

      21:     var ddsCommentRepository = new DynamicDataStoreCommentRepository(dataStoreFactoryMock.Object);

      22:  

      23:     // Act

      24:     var latestComments = ddsCommentRepository.GetLatestComments(3, "sv");

      25:  

      26:     // Assert

      27:     Assert.That(latestComments, Contains.Item(pageCommentList[0]));

      28:     Assert.That(latestComments, !Contains.Item(pageCommentList[1]));      

      29: }

That´s pretty much it, not that hard really. I think this shows how easy testing can be if it is somewhat supported by the framework. Hoping for more of this in upcoming EPiServer versions.

Nov 29, 2010

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