Why do I need to use this plugin?

It is essential that you provide some form of integration testing for your projects and the Invoker Plugin tries to make is easy for you to create integration tests for your Maven Plugins, new Lifecycles, or any other type of Maven component that you've created. Currently the Invoker Plugin forks Maven to execute the specified projects, but it is hoped that soon we will integrate the Maven Embedder into the mix to allow you run your projects in process for great speed.