path: root/t/README

Core GIT Tests
==============

This directory holds many test scripts for core GIT tools.  The
first part of this short document describes how to run the tests
and read their output.

When fixing the tools or adding enhancements, you are strongly
encouraged to add tests in this directory to cover what you are
trying to fix or enhance.  The later part of this short document
describes how your test scripts should be organized.


Running Tests
-------------

The easiest way to run tests is to say "make".  This runs all
the tests.

    *** t0000-basic.sh ***
    ok 1 - .git/objects should be empty after git init in an empty repo.
    ok 2 - .git/objects should have 3 subdirectories.
    ok 3 - success is reported like this
    ...
    ok 43 - very long name in the index handled sanely
    # fixed 1 known breakage(s)
    # still have 1 known breakage(s)
    # passed all remaining 42 test(s)
    1..43
    *** t0001-init.sh ***
    ok 1 - plain
    ok 2 - plain with GIT_WORK_TREE
    ok 3 - plain bare

Since the tests all output TAP (see http://testanything.org) they can
be run with any TAP harness. Here's an example of parallel testing
powered by a recent version of prove(1):

    $ prove --timer --jobs 15 ./t[0-9]*.sh
    [19:17:33] ./t0005-signals.sh ................................... ok       36 ms
    [19:17:33] ./t0022-crlf-rename.sh ............................... ok       69 ms
    [19:17:33] ./t0024-crlf-archive.sh .............................. ok      154 ms
    [19:17:33] ./t0004-unwritable.sh ................................ ok      289 ms
    [19:17:33] ./t0002-gitfile.sh ................................... ok      480 ms
    ===(     102;0  25/?  6/?  5/?  16/?  1/?  4/?  2/?  1/?  3/?  1... )===

prove and other harnesses come with a lot of useful options. The
--state option in particular is very useful:

    # Repeat until no more failures
    $ prove -j 15 --state=failed,save ./t[0-9]*.sh

You can give DEFAULT_TEST_TARGET=prove on the make command (or define it
in config.mak) to cause "make test" to run tests under prove.
GIT_PROVE_OPTS can be used to pass additional options, e.g.

    $ make DEFAULT_TEST_TARGET=prove GIT_PROVE_OPTS='--timer --jobs 16' test

You can also run each test individually from command line, like this:

    $ sh ./t3010-ls-files-killed-modified.sh
    ok 1 - git update-index --add to add various paths.
    ok 2 - git ls-files -k to show killed files.
    ok 3 - validate git ls-files -k output.
    ok 4 - git ls-files -m to show modified files.
    ok 5 - validate git ls-files -m output.
    # passed all 5 test(s)
    1..5

You can pass --verbose (or -v), --debug (or -d), and --immediate
(or -i) command line argument to the test, or by setting GIT_TEST_OPTS
appropriately before running "make".

--verbose::
	This makes the test more verbose.  Specifically, the
	command being run and their output if any are also
	output.

--debug::
	This may help the person who is developing a new test.
	It causes the command defined with test_debug to run.

--immediate::
	This causes the test to immediately exit upon the first
	failed test.

--long-tests::
	This causes additional long-running tests to be run (where
	available), for more exhaustive testing.

--valgrind::
	Execute all Git binaries with valgrind and exit with status
	126 on errors (just like regular tests, this will only stop
	the test script when running under -i).  Valgrind errors
	go to stderr, so you might want to pass the -v option, too.

	Since it makes no sense to run the tests with --valgrind and
	not see any output, this option implies --verbose.  For
	convenience, it also implies --tee.

--tee::
	In addition to printing the test output to the terminal,
	write it to files named 't/test-results/$TEST_NAME.out'.
	As the names depend on the tests' file names, it is safe to
	run the tests with this option in parallel.

--with-dashes::
	By default tests are run without dashed forms of
	commands (like git-commit) in the PATH (it only uses
	wrappers from ../bin-wrappers).  Use this option to include
	the build directory (..) in the PATH, which contains all
	the dashed forms of commands.  This option is currently
	implied by other options like --valgrind and
	GIT_TEST_INSTALLED.

--root=<directory>::
	Create "trash" directories used to store all temporary data during
	testing under <directory>, instead of the t/ directory.
	Using this option with a RAM-based filesystem (such as tmpfs)
	can massively speed up the test suite.

You can also set the GIT_TEST_INSTALLED environment variable to
the bindir of an existing git installation to test that installation.
You still need to have built this git sandbox, from which various
test-* support programs, templates, and perl libraries are used.
If your installed git is incomplete, it will silently test parts of
your built version instead.

When using GIT_TEST_INSTALLED, you can also set GIT_TEST_EXEC_PATH to
override the location of the dashed-form subcommands (what
GIT_EXEC_PATH would be used for during normal operation).
GIT_TEST_EXEC_PATH defaults to `$GIT_TEST_INSTALLED/git --exec-path`.


Skipping Tests
--------------

In some environments, certain tests have no way of succeeding
due to platform limitation, such as lack of 'unzip' program, or
filesystem that do not allow arbitrary sequence of non-NUL bytes
as pathnames.

You should be able to say something like

    $ GIT_SKIP_TESTS=t9200.8 sh ./t9200-git-cvsexport-commit.sh

and even:

    $ GIT_SKIP_TESTS='t[0-4]??? t91?? t9200.8' make

to omit such tests.  The value of the environment variable is a
SP separated list of patterns that tells which tests to skip,
and either can match the "t[0-9]{4}" part to skip the whole
test, or t[0-9]{4} followed by ".$number" to say which
particular test to skip.

Note that some tests in the existing test suite rely on previous
test item, so you cannot arbitrarily disable one and expect the
remainder of test to check what the test originally was intended
to check.


Naming Tests
------------

The test files are named as:

	tNNNN-commandname-details.sh

where N is a decimal digit.

First digit tells the family:

	0 - the absolute basics and global stuff
	1 - the basic commands concerning database
	2 - the basic commands concerning the working tree
	3 - the other basic commands (e.g. ls-files)
	4 - the diff commands
	5 - the pull and exporting commands
	6 - the revision tree commands (even e.g. merge-base)
	7 - the porcelainish commands concerning the working tree
	8 - the porcelainish commands concerning forensics
	9 - the git tools

Second digit tells the particular command we are testing.

Third digit (optionally) tells the particular switch or group of switches
we are testing.

If you create files under t/ directory (i.e. here) that is not
the top-level test script, never name the file to match the above
pattern.  The Makefile here considers all such files as the
top-level test script and tries to run all of them.  A care is
especially needed if you are creating a common test library
file, similar to test-lib.sh, because such a library file may
not be suitable for standalone execution.


Writing Tests
-------------

The test script is written as a shell script.  It should start
with the standard "#!/bin/sh" with copyright notices, and an
assignment to variable 'test_description', like this:

	#!/bin/sh
	#
	# Copyright (c) 2005 Junio C Hamano
	#

	test_description='xxx test (option --frotz)

	This test registers the following structure in the cache
	and tries to run git-ls-files with option --frotz.'


Source 'test-lib.sh'
--------------------

After assigning test_description, the test script should source
test-lib.sh like this:

	. ./test-lib.sh

This test harness library does the following things:

 - If the script is invoked with command line argument --help
   (or -h), it shows the test_description and exits.

 - Creates an empty test directory with an empty .git/objects database
   and chdir(2) into it.  This directory is 't/trash
   directory.$test_name_without_dotsh', with t/ subject to change by
   the --root option documented above.

 - Defines standard test helper functions for your scripts to
   use.  These functions are designed to make all scripts behave
   consistently when command line arguments --verbose (or -v),
   --debug (or -d), and --immediate (or -i) is given.

Do's, don'ts & things to keep in mind
-------------------------------------

Here are a few examples of things you probably should and shouldn't do
when writing tests.

Do:

 - Put all code inside test_expect_success and other assertions.

   Even code that isn't a test per se, but merely some setup code
   should be inside a test assertion.

 - Chain your test assertions

   Write test code like this:

	git merge foo &&
	git push bar &&
	test ...

   Instead of:

	git merge hla
	git push gh
	test ...

   That way all of the commands in your tests will succeed or fail. If
   you must ignore the return value of something (e.g., the return
   after unsetting a variable that was already unset is unportable) it's
   best to indicate so explicitly with a semicolon:

	unset HLAGH;
	git merge hla &&
	git push gh &&
	test ...

 - Check the test coverage for your tests. See the "Test coverage"
   below.

   Don't blindly follow test coverage metrics, they're a good way to
   spot if you've missed something. If a new function you added
   doesn't have any coverage you're probably doing something wrong,
   but having 100% coverage doesn't necessarily mean that you tested
   everything.

   Tests that are likely to smoke out future regressions are better
   than tests that just inflate the coverage metrics.

Don't:

 - exit() within a <script> part.

   The harness will catch this as a programming error of the test.
   Use test_done instead if you need to stop the tests early (see
   "Skipping tests" below).

 - Break the TAP output

   The raw output from your test may be interpreted by a TAP harness. TAP
   harnesses will ignore everything they don't know about, but don't step
   on their toes in these areas:

   - Don't print lines like "$x..$y" where $x and $y are integers.

   - Don't print lines that begin with "ok" or "not ok".

   TAP harnesses expect a line that begins with either "ok" and "not
   ok" to signal a test passed or failed (and our harness already
   produces such lines), so your script shouldn't emit such lines to
   their output.

   You can glean some further possible issues from the TAP grammar
   (see http://search.cpan.org/perldoc?TAP::Parser::Grammar#TAP_Grammar)
   but the best indication is to just run the tests with prove(1),
   it'll complain if anything is amiss.

Keep in mind:

 - Inside <script> part, the standard output and standard error
   streams are discarded, and the test harness only reports "ok" or
   "not ok" to the end user running the tests. Under --verbose, they
   are shown to help debugging the tests.


Skipping tests
--------------

If you need to skip tests you should do so be using the three-arg form
of the test_* functions (see the "Test harness library" section
below), e.g.:

    test_expect_success PERL 'I need Perl' "
        '$PERL_PATH' -e 'hlagh() if unf_unf()'
    "

The advantage of skipping tests like this is that platforms that don't
have the PERL and other optional dependencies get an indication of how
many tests they're missing.

If the test code is too hairy for that (i.e. does a lot of setup work
outside test assertions) you can also skip all remaining tests by
setting skip_all and immediately call test_done: