Database Mocking RSS

• • Reply
  

  BrockAllen

  All-Star

  27432 Points

  4890 Posts

  MVP

  Re: Database Mocking

  Mar 27, 2012 08:51 PM|LINK

  heh, yea.. sorry.

  and the other thing missing from all of this is your "real" repository -- that will do the actual work to connect to a databas and it will be used at runtime.

  Brock Allen | http://brockallen.com
  DevelopMentor | http://www.develop.com
  thinktecture | http://www.thinktecture.com/
• • Reply
  

  Cerberus2589

  Member

  259 Points

  144 Posts

  Re: Database Mocking

  Mar 27, 2012 08:56 PM|LINK

  Yes I understand that the idea is not to test the database work but rather the correct object calls etc.

  I've refactored the code but I still feel like I'm missing someting:

  Tests (missed out the SaveIt call before):

  [Test]
          public void TestMock()
          {
              Mock<IRepository> mockRepository = new Mock<IRepository>();
              var subject = new ThingToTest(mockRepository.Object);
              var someObj = new SomeObject();
              subject.SaveIt(someObj);
              mockRepository.Verify(x => x.Save());
          }

  Thing to Test:

  public class ThingToTest
      {
          private IRepository _repository;
  
          public ThingToTest(IRepository repository)
          {
              this._repository = repository;
          }
  
          public void SaveIt(SomeObject someObject)
          {
              someObject.Save();
          }
      }

  
  
   

• • Reply
  

  BrockAllen

  All-Star

  27432 Points

  4890 Posts

  MVP

  Re: Database Mocking

  Mar 27, 2012 09:02 PM|LINK

  Edit: Sorry for the crappy formatting.

  Yep, looks good. So then what you'd be testing is logic in ThingToTest.SaveIt. For example two tests that confirm some behavior:

  public class ThingToTest
  {
          private IRepository _repository;
  
          public ThingToTest(IRepository repository)
          {
              this._repository = repository;
          }
  
          public void SaveIt(SomeObject someObject)
          {
   if (someObject.SomeValueThatShouldBeNonNull != null)
   {
              _repository.Save(someObject);
   }
          }
      }
  [Test]
  void WhenSomeValueThatShouldBeNonNullIsNonNull_RepositoryShouldBeCalledToSave()
  {

   Mock<IRepository> mockRepository = new Mock<IRepository>();
              var subject = new ThingToTest(mockRepository.Object);
              var someObj = new SomeObject() {SomeValueThatShouldBeNonNull = "this is not null"};
              subject.SaveIt(someObj);
              mockRepository.Verify(x => x.Save());
  

  }
  [Test]
  void WhenSomeValueThatShouldBeNonNullIsNull_RepositoryShouldNotBeCalledToSave()
  {
  

   Mock<IRepository> mockRepository = new Mock<IRepository>();
              var subject = new ThingToTest(mockRepository.Object);
              var someObj = new SomeObject() {SomeValueThatShouldBeNonNull = null};
              subject.SaveIt(someObj);
              mockRepository.Verify(x => x.Save(), Times.Never()); // notice this 2nd param -- it qualifies what we're verifying
  

  }

  Brock Allen | http://brockallen.com
  DevelopMentor | http://www.develop.com
  thinktecture | http://www.thinktecture.com/
  • Edited by BrockAllen on Mar 27, 2012 09:05 PM
  • Edited by BrockAllen on Mar 27, 2012 09:06 PM
• • Reply
  

  Cerberus2589

  Member

  259 Points

  144 Posts

  Re: Database Mocking

  Mar 27, 2012 09:07 PM|LINK

  Ok thanks for the help. The last thing I just want to confirm - The SomeObject object handles code for both mocking and performing the real task (writing to a database), and not just a clone of another object that does the real implementation. Am I correct?

• • Reply
  

  BrockAllen

  All-Star

  27432 Points

  4890 Posts

  MVP

  Re: Database Mocking

  Mar 27, 2012 09:17 PM|LINK

  Cerberus2589

  Ok thanks for the help. The last thing I just want to confirm - The SomeObject object handles code for both mocking and performing the real task (writing to a database), and not just a clone of another object that does the real implementation. Am I correct?

  SomeObject is mainly just a container for data in and data out. If you noticed I editied my post (had a typo). The SomeObject is the param into the repository, not the object that does the DB work. In the test there will be no real database activity, but from the ThingToTest's perspective it doesn't know because all of that is hidden behind the IRepository interface. He doesn't know if it's a real or a fake (and that's a nice level of decoupling).

  Brock Allen | http://brockallen.com
  DevelopMentor | http://www.develop.com
  thinktecture | http://www.thinktecture.com/
  • Edited by BrockAllen on Mar 27, 2012 09:17 PM
• • Reply
  

  Cerberus2589

  Member

  259 Points

  144 Posts

  Re: Database Mocking

  Mar 27, 2012 09:28 PM|LINK

  Ah I think it's all starting to click into place. I'm going to have to do some serious work into this though to really understand it properly. Thanks for your help, original post marked as answer

• • Reply
  

  BrockAllen

  All-Star

  27432 Points

  4890 Posts

  MVP

  Re: Database Mocking

  Mar 27, 2012 09:33 PM|LINK

  Cerberus2589

  Ah I think it's all starting to click into place. I'm going to have to do some serious work into this though to really understand it properly. Thanks for your help, original post marked as answer

  Yea, it takes a while. I'd say it took me a year before I even got comfortable with the style.

  Brock Allen | http://brockallen.com
  DevelopMentor | http://www.develop.com
  thinktecture | http://www.thinktecture.com/