Testing SharePoint was always an issue, because SharePoint has number of classes that are sealed and/or does not have public constructors. SharePoint's API consists heavily of sealed classes and classes with internal constructors. None of existed unit-testing frameworks provided ability to mock such classes.

Guys from TypeMock (http://www.typemock.com) did fantastic work, providing really powerful framework to mock such classes, which were not covered with existed frameworks, like RhinoMock and Moq or NUnit mocks.

And today, they announced Isolator for sharepoint:

It is almost the same as Typemock Isolator, but will only work on APIs that are directly connected with sharepoint’s API. That means that if you only need to test sharepoint stuff, you can get a powerful product, for a much cheaper price than the full Isolator (you can always upgrade later if you need to isolate more APIs).

Info for masses, how to get free licence:

Typemock are offering their new product for unit testing SharePoint called Isolator For SharePoint, for a special introduction price. it is the only tool that allows you to unit test SharePoint without a SharePoint server. To learn more click here.

The first 50 bloggers who blog this text in their blog and tell us about it, will get a Full Isolator license, Free. for rules and info click here.