Provides an easy method to switch between a core and contrib version of a module. This comes in handy when working with or developing a contrib version of a core module and you want to quickly switch between the two to compare or use the core version.
SimpleTest 7.x-2.x, which will override core SimpleTest, does not provide the same testing API and thus does not allow for running core tests. Using switcheroo you can quickly switch between the two to run your 2.x api tests or core tests.
Please note that at the current time this module does not allow you to run tests for an overridden module since the testing system will use the default behavior (aka the non-overridden module) in the test database. Something to look at in the future.