内容简介:Bats is aA 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 written in Bash, but you can use it to test any UNIX prog
Bats: 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. 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 --tap
option.
$ bats --tap addition.bats 1..2 ok 1 addition using bc ok 2 addition using dc
Test suites
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.
Writing tests
Each Bats test file is evaluated n+1 times, where n is the number of test cases in the file. The first run counts the number of test cases, then iterates over the test cases and executes each one in its own process.
For more details about how Bats evaluates test files, see Bats Evaluation Process on the wiki.
run
: Test other commands
Many Bats tests need to run a command and then make assertions about
its 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 ] [ "${lines[0]}" = "usage: foo <filename>" ] }
load
: Share common code
You may want to share common code across multiple test files. Bats
includes a convenient load
command for sourcing a Bash source file
relative to the location of the current test file. For example, if you
have a Bats test in test/foo.bats
, the command
load test_helper
will source the script test/test_helper.bash
in your test file. This
can be useful for sharing functions to set up your environment or load
fixtures.
skip
: Easily skip tests
Tests can be skipped by using the skip
command at the point in a
test you wish to skip.
@test "A test I don't want to execute for now" { skip run foo [ "$status" -eq 0 ] }
Optionally, you may include a reason for skipping:
@test "A test I don't want to execute for now" { skip "This command will return zero soon, but not now" run foo [ "$status" -eq 0 ] }
Or you can skip conditionally:
@test "A test which should run" { if [ foo != bar ]; then skip "foo isn't bar" fi run foo [ "$status" -eq 0 ] }
setup
and teardown
: Pre- and post-test hooks
You can 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.
Code outside of test cases
You can include code in your test file outside of @test
functions.
For example, this may be useful if you want to check for dependencies
and fail immediately if they're not present. However, any output that
you print in code outside of @test
, setup
or teardown
functions
must be redirected to stderr
( >&2
). Otherwise, the output may
cause Bats to fail by polluting the TAP stream on stdout
.
Special variables
There are several global variables you can use to introspect on Bats tests:
$BATS_TEST_FILENAME $BATS_TEST_DIRNAME $BATS_TEST_NAMES $BATS_TEST_NAME $BATS_TEST_DESCRIPTION $BATS_TEST_NUMBER $BATS_TMPDIR
Installing Bats from source
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.
Support
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.
For real-world examples from open-source projects using Bats, see Projects Using Bats on the wiki.
To learn how to set up your editor for Bats syntax highlighting, see Syntax Highlighting on the wiki.
Version history
0.4.0 (August 13, 2014)
- Improved the display of failing test cases. Bats now shows the source code of failing test lines, along with full stack traces including function names, filenames, and line numbers.
- Improved the display of the pretty-printed test summary line to include the number of skipped tests, if any.
- Improved the speed of the preprocessor, dramatically shortening test and suite startup times.
-
Added support for absolute pathnames to the
load
helper. -
Added support for single-line
@test
definitions. - Added bats(1) and bats(7) manual pages.
-
Modified the
bats
command to default to TAP output when the$CI
variable is set, to better support environments such as Travis CI.
0.3.1 (October 28, 2013)
- Fixed an incompatibility with the pretty formatter in certain environments such as tmux.
- Fixed a bug where the pretty formatter would crash if the first line of a test file's output was invalid TAP.
0.3.0 (October 21, 2013)
--tap skip bats -e
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.
© 2014 Sam Stephenson. Bats is released under an MIT-style license;
see LICENSE
for details.
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