bats - Man Page

Bash Automated Testing System

Examples (TL;DR)

Synopsis

Usage: bats [Options] tests bats [-h | -v]

tests is the path to a Bats test file, or the path to a directory containing Bats test files (ending with ".bats")

Description

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.

Running 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.

Filtering Tests

There are multiple mechanisms to filter which tests to execute:

--FILTER-TAGS <var>TAG-LIST</var>

Tags can be used for finegrained filtering of which tests to run via --filter-tags. This accepts a comma separated list of tags. Only tests that match all of these tags will be executed. For example, bats --filter-tags a,b,c will pick up tests with tags a,b,c, but not tests that miss one or more of those tags.

Additionally, you can specify negative tags via bats --filter-tags a,!b,c, which now won´t match tests with tags a,b,c, due to the b, but will select a,c. To put it more formally, --filter-tags is a boolean conjunction.

To allow for more complex queries, you can specify multiple --filter-tags. A test will be executed, if it matches at least one of them. This means multiple --filter-tags form a boolean disjunction.

A query of --filter-tags a,!b --filter-tags b,c can be translated to: Execute only tests that (have tag a, but not tag b) or (have tag b and c).

An empty tag list matches tests without tags.

Options

-c,  --count

Count the number of test cases without running any tests

--code-quote-style <style>

A two character string of code quote delimiters or custom which requires setting $BATS_BEGIN_CODE_QUOTE and $BATS_END_CODE_QUOTE. Can also be set via $BATS_CODE_QUOTE_STYLE.

-f, --filter <regex>

Filter test cases by names matching the regular expression

-F, --formatter <type>

Switch between formatters: pretty (default), tap (default w/o term), tap13, junit, /<absolute path to formatter>

--filter-status <status>

Only run tests with the given status in the last completed (no CTRL+C/SIGINT) run. Valid status values are: failed - runs tests that failed or were not present in the last run missed - runs tests that were not present in the last run

--filter-tags <comma-separated-tag-list>

Only run tests that match all the tags in the list (&&). You can negate a tag via prepending !. Specifying this flag multiple times allows for logical or (||): --filter-tags A,B --filter-tags A,!C matches tags (A && B) || (A && !C)

--gather-test-outputs-in <directory>

Gather the output of failing and passing tests as files in directory

-h,  --help

Display this help message

-j, --jobs <jobs>

Number of parallel jobs (requires GNU parallel)

--no-tempdir-cleanup

Preserve test output temporary directory

--no-parallelize-across-files

Serialize test file execution instead of running them in parallel (requires --jobs >1)

--no-parallelize-within-files

Serialize test execution within files instead of running them in parallel (requires --jobs >1)

--report-formatter <type>

Switch between reporters (same options as --formatter)

-o, --output <dir>

Directory to write report files

-p,  --pretty

Shorthand for "--formatter pretty"

--print-output-on-failure

Automatically print the value of $output on failed tests

-r,  --recursive

Include tests in subdirectories

--show-output-of-passing-tests

Print output of passing tests

-t,  --tap

Shorthand for "--formatter tap"

-T,  --timing

Add timing information to tests

-x,  --trace

Print test commands as they are executed (like set -x)

--verbose-run

Make run print $output by default

-v,  --version

Display the version number

Output

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
1..2
ok 1 addition using bc
ok 2 addition using dc

Exit Status

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

See Also

Bats wiki: https://github.com/bats-core/bats-core/wiki/

bash(1), bats(7)

Referenced By

bats(7).

November 2022 bats-core Bash Automated Testing System