Developer JUnit Testing for web applications using embedded tomcat

I have a platform which comprises of 8 wars files and is deployed on tomcat as of today. I want to start writing unit tests for my application components. Essentially, I want to be able to make a call to servlet and inspect its output but at the same time also have the provision to tap into the internal cache classes and database querying to ensure that the request did really pass. These internal classes will be available in the classpath.

So, my wars need to be running on a tomcat instance against which I execute my tests and inspect cache/database. I dont want to mock the interfaces nor test the jsp's, so as of now I can think of using embedded tomcat but cannot find any apt article to guide me through.

Can someone please suggest any appropriate documentation for me to understand how this can be achieved? (or) May be other frameworks which I can look at.

Thanks in advance.