bin | ||
libexec | ||
test | ||
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install.sh | ||
LICENSE | ||
README.md |
Bats: the Bash Automated Testing System
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.
#!/usr/bin/env bats
@test "addition using bc" {
result="$(echo 2+2 | bc)"
[ "$result" -eq 4 ]
}
@test "addition using dc" {
result="$(echo 2 2+p | dc)"
[ "$result" -eq 4 ]
}
Bats is most useful when testing software 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.
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, and
the results are written to standard output in human-readable TAP
format.
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.
$ bats addition.bats
1..2
ok 1 addition using bc
ok 2 addition using dc
$ echo $?
0
You can also define special setup
and teardown
functions which run
before and after each test case, respectively. Use these to load
fixtures, set up your environment, and clean up when you're done.
Test suites
You can also invoke the bats
interpreter with a path to a directory
containing multiple .bats
files. Bats will run each test file
individually and aggregate the results. If any test case fails, bats
exits with a 1
status code.
Helpers and introspection
The run helper
If you're using Bats, you're probably most interested in testing a
command's exit status and output. Bats includes a run
helper that
invokes its arguments as a command, saves the exit status and output
into special global variables, and then returns with a 0
status code
so you can continue to make assertions in your test case.
For example, let's say you're testing that the foo
command, when
passed a nonexistent filename, exits with a 1
status code and prints
an error message.
@test "invoking foo with a nonexistent file prints an error" {
run foo nonexistent_filename
[ "$status" -eq 1 ]
[ "$output" = "foo: no such file 'nonexistent_filename'" ]
}
The $status
variable contains the status code of the command, and
the $output
variable contains the combined contents of the command's
standard output and standard error streams.
A third special variable, the $lines
array, is available for easily
accessing individual lines of output. For example, if you want to test
that invoking foo
without any arguments prints usage information on
the first line:
@test "invoking foo without arguments prints usage" {
run foo
[ "$status" -eq 1 ]
[ "${lines[0]}" = "usage: foo <filename>" ]
}
The load command
You may want to share common code across multiple test files. Bats
includes a convenient load
command for sourcing a Bash source file
relative to the location of the current test file. For example, if you
have a Bats test in test/foo.bats
, the command
load test_helper
will source the script test/test_helper.bash
in your test file. This
can be useful for sharing functions to set up your environment or load
fixtures.
Special variables
There are several global variables you can use to introspect on Bats tests:
$BATS_TEST_FILENAME
is the fully expanded path to the Bats test file.$BATS_TEST_DIRNAME
is the directory in which the Bats test file is located.$BATS_TEST_NAMES
is an array of function names for each test case.$BATS_TEST_NAME
is the name of the function containing the current test case.$BATS_TEST_DESCRIPTION
is the description of the current test case.$BATS_TEST_NUMBER
is the (1-based) index of the current test case in the test file.$BATS_TMPDIR
is the location to a directory that may be used to store temporary files.
Installing Bats
Check out a copy of the Bats repository. Then, either add the Bats
bin
directory to your $PATH
, or run the provided install.sh
command with the location to the prefix in which you want to install
Bats. For example, to install Bats into /usr/local
,
$ git clone https://github.com/sstephenson/bats.git
$ cd bats
$ ./install.sh /usr/local
Note that you may need to run install.sh
with sudo
if you do not
have permission to write to the installation prefix.
Syntax Highlighting
- Bats.tmbundle from Dr Nic Williams adds Bats syntax highlighting support for TextMate.
Development
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.
See the Bats test suite for examples.
Version history
0.2.0 (November 16, 2012)
- Added test suite support. The
bats
command accepts a directory name containing multiple test files to be run in aggregate. - Added the ability to count the number of test cases in a file or
suite by passing the
-c
flag tobats
. - Preprocessed sources are cached between test case runs in the same file for better performance.
0.1.0 (December 30, 2011)
- Initial public release.
© 2011 Sam Stephenson. Bats is released under an MIT-style license;
see LICENSE
for details.