Bats comes with two manual pages. After installation you can view them with man 1 bats (usage manual) and man 7 bats (writing test files manual). Also, you can view the available command line options that Bats supports by calling Bats with the -h or --help options. These are the options that Bats currently supports:

Bats 1.11.0
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")

  -c, --count               Count 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 $BATS_CODE_QUOTE_STYLE
  --line-reference-format   Controls how file/line references e.g. in stack traces are printed:
                              - comma_line (default): a.bats, line 1
                              - colon:  a.bats:1
                              - uri: file:///tests/a.bats:1
                              - custom: provide your own via defining bats_format_file_line_reference_custom
                                        with parameters <filename> <line>, store via `printf -v "$output"`
  -f, --filter <regex>      Only run tests that match the regular expression
  --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)
  -F, --formatter <type>    Switch between formatters: pretty (default),
                              tap (default w/o term), tap13, junit, /<absolute path to formatter>
  --gather-test-outputs-in <directory>
                            Gather the output of failing *and* passing tests
                            as files in directory (if existing, must be empty)
  -h, --help                Display this help message
  -j, --jobs <jobs>         Number of parallel jobs (requires GNU parallel or shenwei356/rush)
  --parallel-binary-name    Name of parallel binary
  --no-tempdir-cleanup      Preserve test output temporary directory
                            Serialize test file execution instead of running
                            them in parallel (requires --jobs >1)
                            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 (must exist)
  -p, --pretty              Shorthand for "--formatter pretty"
  --print-output-on-failure Automatically print the value of `$output` on failed tests
  -r, --recursive           Include tests in subdirectories
                            Print output of passing tests
  -t, --tap                 Shorthand for "--formatter tap"
  -T, --timing              Add timing information to tests
  -x, --trace               Print test commands as they are executed (like `set -x`)
  --verbose-run             Make `run` print `$output` by default
  -v, --version             Display the version number

  For more information, see

To run your tests, invoke the bats interpreter with one or more paths to test files ending with the .bats extension, or paths to directories containing test files. (bats will only execute .bats files at the top level of each directory; it will not recurse unless you specify the -r flag.)

Test cases from each file 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.

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 --formatter tap option.

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

With --formatter junit, it is possible to output junit-compatible report files.

$ bats --formatter junit addition.bats
ok 1 addition using bc
ok 2 addition using dc

If you have your own formatter, you can use an absolute path to the executable to use it:

$ bats --formatter /absolute/path/to/my-formatter addition.bats
addition using bc WORKED
addition using dc FAILED

You can also generate test report files via --report-formatter which accepts the same options as --formatter. By default, the file is stored in the current workdir. However, it may be placed elsewhere by specifying the --output flag.

$ bats --report-formatter junit addition.bats --output /tmp
ok 1 addition using bc
ok 2 addition using dc

$ cat /tmp/report.xml
<?xml version="1.0" encoding="UTF-8"?>
<testsuites time="0.073">
<testsuite name="addition.bats" tests="2" failures="0" errors="0" skipped="0">
    <testcase classname="addition.bats" name="addition using bc" time="0.034" />
    <testcase classname="addition.bats" name="addition using dc" time="0.039" />

Parallel Execution

New in version 1.0.0.

By default, Bats will execute your tests serially. However, Bats supports parallel execution of tests (provided you have GNU parallel or a compatible replacement installed) using the --jobs parameter. This can result in your tests completing faster (depending on your tests and the testing hardware).

Ordering of parallelised tests is not guaranteed, so this mode may break suites with dependencies between tests (or tests that write to shared locations). When enabling --jobs for the first time be sure to re-run bats multiple times to identify any inter-test dependencies or non-deterministic test behaviour.

When parallelizing, the results of a file only become visible after it has been finished. You can use --no-parallelize-across-files to get immediate output at the cost of reduced overall parallelity, as parallelization will only happen within files and files will be run sequentially.

If you have files where tests within the file would interfere with each other, you can use --no-parallelize-within-files to disable parallelization within all files. If you want more fine-grained control, you can export BATS_NO_PARALLELIZE_WITHIN_FILE=true in setup_file() or outside any function to disable parallelization only within the containing file.