JUnit

JUnit is an open source unit testing tool for Java programming language. It is important tool for test-driven development and deployment.

Features:
     1. Preparation of input data and setup/creation of fake objects
     2. Loading databases with a specific known set of data
     3. It provides annotations so that test classes can have fixture run before or after every test
     4. JUnit provides support for writing and running tests
     5. It provides annotations to identify test methods
     6. Provides assertions for testing expected results
     7. JUnit tests allow writing codes faster, which increases quality

More Information and Official Website:
Download : http://junit.org/junit4/