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Typemock Isolator Review

Typemocks Isolator has been around for quite some time now, and I was given the opportunity to review version 7.4 of the product. Isolator is best known for the ability to test legacy code, i.e. code that with other mocking frameworks isn’t possible to mock or stub. Typemock ships the Isolator package with a lot more features than the ordinary mocking framework. Short list given below. I will consider each of these in this review.

Features of Typemock Isolator

  • Smart Runner
  • Coverage
  • Mock Interfaces
  • Mock Everything
  • Test Legacy Code
  • Test Code Autocompletion

Smart Runner
The smart runner allows for tests to be run when building your solution. At startup it examines all your current tests to get a baseline, and from that it should in for this session when rebuilding only run test relevant for the changes made. It sounds smart but In this context, I would rather use something like NCrunch. The good news is that NCrunch has support for Typemock Isolator. Maybe for larger application this would be a nice feature, especially if running the entire battery of tests takes more time than building your application.

The coverage analyzer part is nice touch where you can hook up with your favorite test coverage analyzer for example DotCover or NCover. But, and this is a big but, for me with the test runner included with Typemock I simply can’t find a window or output which shows the entire test coverage for my application, not even for a single class. Maybe I’m missing something. But all I can see on each methods in each class. See images below.

With that said I do like the information on coverage for methods where you easily can see which test covers the code. This is shown in the illustration below


Mock interfaces, Mock Everything and Test Legacy code
As with any mocking framework, e.g. Nsubstitute, Rhino, Moq, you can with the Isolator mock virtual methods, interfaces and abstract classes and methods. In addition, it is possible to mock statics-, private- methods and classes which cannot be mocked with standard mocking frameworks. As promised you can mock everything with Isolator.

I previously wrote a blog post where I stubbed out a lot of Sitecore functionality. You can read the blog post [Mocking Sitecore with Typemock Isolator Here].

Test Code Autocompletion
The intellisense for autocompletion for fakes is one of the features which quickly became one of my favorite things about Isolator. This feature really speeds up the process of writing tests.
As a standard this feature isn’t enabled to begin with. You will have to enable it under
Tools->Add-in manager
As illustrated here:


Instead of writing Arrange part of a unit test, it automatically generates it for you using the shortcut “alt+7” .


  • Mock/Stub Everything
  • Test Code Autocompletion – Really liking this one.
  • Easy to use syntax


  • Missing Application/Class Test Coverage
  • Price

With the Isolator from Typemock you get much more than a standard mocking framework, you get a feature rich add-in for Visual Studio. For those only looking for an Isolation framework, this might be a bit too much. But if you are working in an organization with a lot of “Legacy Code” or trying to introduce unit testing or even TDD, I think the Isolator will offer you some really good assistance. It comes with a price tag but you also get a lot more than a standard isolation framework. For me working with Sitecore I need something like Isolator where you can mock/stub everything. But there are other alternatives out there for example Microsoft Fakes or JustMock, with Fakes coming free with Update 2 for Visual Studio, fakes syntax isn’t as intuitive as Typemocks Isolator..

If you are interested Typemock offers a lot of really good webinars. You can find a list of previous webinars [here]. Also if you follow them on twitter @Typemock you can be notified about upcoming webinars. With these webinars you can get a good introduction to unit testing and TDD, and how to introduce Testing into to your organization.

Categories: .Net, C#, Unit Testing Tags: , ,
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