Functional tests for command line applications
Cram is a functional testing framework for command line applications. Cram tests look like snippets of interactive shell sessions. Cram runs each command and compares the command output in the test with the command's actual output.
Here's a snippet from
Cram's own test suite_::
The $PYTHON environment variable should be set when running this test from Python.
$ [ -n "$PYTHON" ] || PYTHON="
which python" $ [ -n "$PYTHONPATH" ] || PYTHONPATH="$TESTDIR/.." && export PYTHONPATH $ if [ -n "$COVERAGE" ]; then > coverage erase > alias cram="
which coveragerun --branch -a $TESTDIR/../scripts/cram" > else > alias cram="$PYTHON $TESTDIR/../scripts/cram" > fi $ command -v md5 > /dev/null || alias md5=md5sum
$ cram -h [Uu]sage: cram [OPTIONS] TESTS... (re)
[Oo]ptions: (re) -h, --help show this help message and exit -V, --version show version information and exit -q, --quiet don't print diffs -v, --verbose show filenames and test status -i, --interactive interactively merge changed test output -d, --debug write script output directly to the terminal -y, --yes answer yes to all questions -n, --no answer no to all questions -E, --preserve-env don't reset common environment variables --keep-tmpdir keep temporary directories --shell=PATH shell to use for running tests (default: /bin/sh) --shell-opts=OPTS arguments to invoke shell with --indent=NUM number of spaces to use for indentation (default: 2) --xunit-file=PATH path to write xUnit XML output
The format in a nutshell:
Cram tests use the
Lines beginning with two spaces, a dollar sign, and a space are run in the shell.
Lines beginning with two spaces, a greater than sign, and a space allow multi-line commands.
All other lines beginning with two spaces are considered command output.
Output lines ending with a space and the keyword
(re)are matched as
Perl-compatible regular expressions_.
Lines ending with a space and the keyword
(glob)are matched with a glob-like syntax. The only special characters supported are
?. Both characters can be escaped using
\, and the backslash can be escaped itself.
Output lines ending with either of the above keywords are always first matched literally with actual command output.
Lines ending with a space and the keyword
(no-eol)will match actual output that doesn't end in a newline.
Actual output lines containing unprintable characters are escaped and suffixed with a space and the keyword
(esc). Lines matching unprintable output must also contain the keyword.
Anything else is a comment.
.. Cram's own test suite: https://bitbucket.org/brodie/cram/src/0.6/tests/cram.t .. _Perl-compatible regular expressions: https://en.wikipedia.org/wiki/PerlCompatibleRegularExpressions
cram-0.7.tar.gz_ (32 KB, requires Python 2.4-2.7 or Python 3.1 or newer)
.. _cram-0.7.tar.gz: https://bitheap.org/cram/cram-0.7.tar.gz
Install Cram using make::
$ wget https://bitheap.org/cram/cram-0.7.tar.gz $ tar zxvf cram-0.7.tar.gz $ cd cram-0.7 $ make install
Cram will print a dot for each passing test. If a test fails, a
unified context diff_ is printed showing the test's expected output and the actual output. Skipped tests (empty tests and tests that exit with return code
80) are marked with
sinstead of a dot.
For example, if we run Cram on
its own example tests_::
.s.! --- examples/fail.t +++ examples/fail.t.err @@ -3,21 +3,22 @@ $ echo 1 1 $ echo 1 - 2 + 1 $ echo 1 1
$ echo 1
Offset regular expression:
$ printf 'foo\nbar\nbaz\n\n1\nA\[email protected]\n' foo
\d (re) [A-Z] (re)
Cram will also write the test with its actual output to
examples/fail.t.err, allowing you to use other diff tools. This file is automatically removed the next time the test passes.
When you're first writing a test, you might just write the commands and run the test to see what happens. If you run Cram with
--interactive, you'll be prompted to merge the actual output back into the test. This makes it easy to quickly prototype new tests.
You can specify a default set of options by creating a
.cramrcfile. For example::
[cram] verbose = True indent = 4
Is the same as invoking Cram with
To change what configuration file Cram loads, you can set the
CRAMRCenvironment variable. You can also specify command line options in the
Note that the following environment variables are reset before tests are run:
TMPare set to the test runner's
LANGUAGEare set to
TZis set to
COLUMNSis set to
80. (Note: When using
--shell=zsh, this cannot be reset. It will reflect the actual terminal's width.)
GREP_OPTIONSare set to an empty string.
Cram also provides the following environment variables to tests:
CRAMTMP, set to the test runner's temporary directory.
TESTDIR, set to the directory containing the test file.
TESTFILE, set to the basename of the current test file.
TESTSHELL, set to the value specified by
Also note that care should be taken with commands that close the test shell's
stdin. For example, if you're trying to invoke
sshin a test, try adding the
-noption to prevent it from closing
stdin. Similarly, if you invoke a daemon process that inherits
stdoutand fails to close it, it may cause Cram to hang while waiting for the test shell's
stdoutto be fully closed.
.. unified context diff: https://en.wikipedia.org/wiki/Diff#Unifiedformat .. _its own example tests: https://bitbucket.org/brodie/cram/src/default/examples/
Download the official development repository using Mercurial_::
hg clone https://bitbucket.org/brodie/cram
git clone https://github.com/brodie/cram.git
Test Cram using Cram::
pip install -r requirements.txt make test
Visit Bitbucket_ or GitHub_ if you'd like to fork the project, watch for new changes, or report issues.
.. _Mercurial: http://mercurial.selenic.com/ .. _Git: http://git-scm.com/ .. _coverage.py: http://nedbatchelder.com/code/coverage/ .. _Bitbucket: https://bitbucket.org/brodie/cram .. _GitHub: https://github.com/brodie/cram