One of the original automated unit testing frameworks, JUnit has been in use at Eclipse for over a decade. Part of Eclipse's quality can be attributed to the set of automated unit tests that exercise both the UI and the non-UI (headless) components.
JUnit works by creating a test case with one or more tests—which usually correspond to a class and methods respectively. Conventionally, test classes end with Test
but this is not a requirement. Multiple test cases can be aggregated into test suites, although implicitly a project becomes its own test suite.