shunit is just a set of bash functions for producing unit test output from bash scripts. I wrote this library because I often found myself writing things in bash whose output I wanted to consume as discrete pass/fail tasks into Bamboo, so I wrote the junit functions. Then later on, I got sick and tired of (as a human) reading junit output, so I wrote the tunit functions, so my scripts could output tunit or junit depending on which flags I passed.
Complete documentation is inside the functions (each function has --help) in ./lib/*unit.sh. A pair of complete examples are in tests/*unit.sh.