You were asked by your manager to execute complete unit test (white box testing) for StringUtils Java class, written by a developer who suddenly left the team. You are provided the source code (StringUtils.java) and you are to write JUnit test cases for it. You are to assume that code description is correct for what each method is supposed to do and the code is supposed to match it.
Objectives:
Define, implement, and execute complete and thorough unit test on the given Java class (StringUtils.java).