Bats is a TAP-compliant testing framework for Bash. It provides a simple way to verify that the UNIX programs you write behave as expected. A Bats test file is a Bash script with special syntax for defining test cases. Under the hood, each test case is just a function with a description. Bats is most useful when testing software is written in Bash, but you can use it to test any UNIX program. Test cases consist of standard shell commands. Bats makes use of Bash's errexit (set -e) option when running test cases. If every command in the test case exits with a 0 status code (success), the test passes. In this way, each line is an assertion of truth. The Bats source code repository is hosted on GitHub. There you can file bugs on the issue tracker or submit tested pull requests for review.