bats(1) Bash Automated Testing System


bats [-c] [-p | -t] test [test ...]

test is the path to a Bats test file, or the path to a directory containing Bats test files.


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.

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.

See bats(7) for more information on writing Bats tests.


To run your tests, invoke the bats interpreter with a path to a test file. The file's test cases are run sequentially and in isolation. If all the test cases pass, bats exits with a 0 status code. If there are any failures, bats exits with a 1 status code.

You can invoke the bats interpreter with multiple test file arguments, or with a path to a directory containing multiple .bats files. Bats will run each test file individually and aggregate the results. If any test case fails, bats exits with a 1 status code.


-c, --count
Count the number of test cases without running any tests
-h, --help
Display help message
-p, --pretty
Show results in pretty format (default for terminals)
-t, --tap
Show results in TAP format
-v, --version
Display the version number


When you run Bats from a terminal, you'll see output as each test is performed, with a check-mark next to the test's name if it passes or an "X" if it fails.
$ bats addition.bats
 ✓ addition using bc
 ✓ addition using dc
2 tests, 0 failures

If Bats is not connected to a terminal--in other words, if you run it from a continuous integration system or redirect its output to a file--the results are displayed in human-readable, machine-parsable TAP format. You can force TAP output from a terminal by invoking Bats with the --tap option.

$ bats --tap addition.bats
ok 1 addition using bc
ok 2 addition using dc


The bats interpreter exits with a value of 0 if all test cases pass, or 1 if one or more test cases fail.


(c) 2014 Sam Stephenson

Bats is released under the terms of an MIT-style license.