Why Unit Testing?

The notion of programmers writing tests to verify their own code was a shock to many in 2003, despite the fact that JUnit had been around for five years at the time.

Over a decade later, unit testing is a skill expected of most developers, especially those who work with Java. Companies will often ask how a developer tests their code. They might also ask whether or not we test-drive our code, use things known as mock objects, or have any thoughts about how to deal with legacy dependency challenges.