gUnit is a "Unit Test" framework for ANTLR grammars. It provides a simple
 way to write and run automated tests for ANTLR grammars in a manner similar
 to Java unit testing framework jUnit. The basic idea is to create a bunch of
 input/output pairs for rules in a grammar and gUnit will verify the expected
 output/result. The input can be a single line or multiple lines of strings or
 even an external file. The output can be simply success or failure, an
 abstract syntax tree (AST), a rule return value, or some text output which
 could be a rule's template return value. The current version of gUnit has 2
 main functions, interpreter and jUnit generator. The interpreter interprets
 your gUnit script and runs unit tests using Java reflection to invoke methods
 in your parser objects. The generator, on the other hand, translates your
 gUnit script to jUnit Java code that you can compile and execute by hand.