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https://github.com/sstephenson/bats

Bash Automated Testing System
https://github.com/sstephenson/bats

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Bash Automated Testing System

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README 

        
# Bats: Bash Automated Testing System



Bats is a [TAP](http://testanything.org)-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.



```bash

#!/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](http://testanything.org).



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](https://github.com/sstephenson/bats/wiki/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.



```bash

@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:



```bash

@test "invoking foo without arguments prints usage" {

  run foo

  [ "$status" -eq 1 ]

  [ "${lines[0]}" = "usage: foo " ]

}

```



### `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



```bash

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.



```bash

@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:



```bash

@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:



```bash

@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` 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 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](https://github.com/sstephenson/bats). 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](https://github.com/sstephenson/bats/wiki/Projects-Using-Bats)

on the wiki.



To learn how to set up your editor for Bats syntax highlighting, see

[Syntax Highlighting](https://github.com/sstephenson/bats/wiki/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)



* Improved formatting for tests run from a terminal. Failing tests

  are now colored in red, and the total number of failing tests is

  displayed at the end of the test run. When Bats is not connected to

  a terminal (e.g. in CI runs), or when invoked with the `--tap` flag,

  output is displayed in standard TAP format.

* Added the ability to skip tests using the `skip` command.

* Added a message to failing test case output indicating the file and

  line number of the statement that caused the test to fail.

* Added "ad-hoc" test suite support. You can now invoke `bats` with

  multiple filename or directory arguments to run all the specified

  tests in aggregate.

* Added support for test files with Windows line endings.

* Fixed regular expression warnings from certain versions of Bash.

* Fixed a bug running tests containing lines that begin with `-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 to `bats`.

* 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.