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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. --verbose-only=<pattern>:: Like --verbose, but the effect is limited to tests with numbers matching <pattern>. The number matched against is simply the running count of the test within the file. --debug:: This may help the person who is developing a new test. It causes the command defined with test_debug to run. The "trash" directory (used to store all temporary data during testing) is not deleted even if there are no failed tests so that you can inspect its contents after the test finished. --immediate:: This causes the test to immediately exit upon the first failed test. Cleanup commands requested with test_when_finished are not executed if the test failed, in order to keep the state for inspection by the tester to diagnose the bug. --long-tests:: This causes additional long-running tests to be run (where available), for more exhaustive testing. --valgrind=<tool>:: Execute all Git binaries under valgrind tool <tool> and exit with status 126 on errors (just like regular tests, this will only stop the test script when running under -i). 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. <tool> defaults to 'memcheck', just like valgrind itself. Other particularly useful choices include 'helgrind' and 'drd', but you may use any tool recognized by your valgrind installation. As a special case, <tool> can be 'memcheck-fast', which uses memcheck but disables --track-origins. Use this if you are running tests in bulk, to see if there are _any_ memory issues. Note that memcheck is run with the option --leak-check=no, as the git process is short-lived and some errors are not interesting. In order to run a single command under the same conditions manually, you should set GIT_VALGRIND to point to the 't/valgrind/' directory and use the commands under 't/valgrind/bin/'. --valgrind-only=<pattern>:: Like --valgrind, but the effect is limited to tests with numbers matching <pattern>. The number matched against is simply the running count of the test within the file. --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. 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, consider using a helper function (e.g. use sane_unset instead of unset, in order to avoid unportable return value for unsetting a variable that was already unset), or prepending the command with test_might_fail or test_must_fail. - Check the test coverage for your tests. See the "Test coverage" below. Don't blindly follow test coverage metrics; if a new function you added doesn't have any coverage, then 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. - When a test checks for an absolute path that a git command generated, construct the expected value using $(pwd) rather than $PWD, $TEST_DIRECTORY, or $TRASH_DIRECTORY. It makes a difference on Windows, where the shell (MSYS bash) mangles absolute path names. For details, see the commit message of 4114156ae9. Don't: - exit() within a <script> part. The harness will catch this as a programming error of the test. Use test_done instead if you need to stop the tests early (see "Skipping tests" below). - use '! git cmd' when you want to make sure the git command exits with failure in a controlled way by calling "die()". Instead, use 'test_must_fail git cmd'. This will signal a failure if git dies in an unexpected way (e.g. segfault). On the other hand, don't use test_must_fail for running regular platform commands; just use '! cmd'. - use perl without spelling it as "$PERL_PATH". This is to help our friends on Windows where the platform Perl often adds CR before the end of line, and they bundle Git with a version of Perl that does not do so, whose path is specified with $PERL_PATH. - use sh without spelling it as "$SHELL_PATH", when the script can be misinterpreted by broken platform shell (e.g. Solaris). - chdir around in tests. It is not sufficient to chdir to somewhere and then chdir back to the original location later in the test, as any intermediate step can fail and abort the test, causing the next test to start in an unexpected directory. Do so inside a subshell if necessary. - 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 $y are integers. - Don't print lines that begin with "ok" or "not ok". TAP harnesses expect a line that begins with either "ok" and "not ok" to signal a test passed or failed (and our harness already produces such lines), so your script shouldn't emit such lines to their output. You can glean some further possible issues from the TAP grammar (see http://search.cpan.org/perldoc?TAP::Parser::Grammar#TAP_Grammar) but the best indication is to just run the tests with prove(1), it'll complain if anything is amiss. Keep in mind: - Inside <script> part, the standard output and standard error streams are discarded, and the test harness only reports "ok" or "not ok" to the end user running the tests. Under --verbose, they are shown to help debugging the tests. Skipping tests -------------- If you need to skip tests you should do so by using the three-arg form of the test_* functions (see the "Test harness library" section below), e.g.: test_expect_success PERL 'I need Perl' ' "$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: if ! test_have_prereq PERL then skip_all='skipping perl interface tests, perl not available' test_done fi The string you give to skip_all will be used as an explanation for why the test was skipped. End with test_done ------------------ Your script will be a sequence of tests, using helper functions from the test harness library. At the end of the script, call 'test_done'. Test harness library -------------------- There are a handful helper functions defined in the test harness library for your script to use. - test_expect_success [<prereq>] <message> <script> Usually takes two strings as parameters, and evaluates the <script>. If it yields success, test is considered successful. <message> should state what it is testing. Example: test_expect_success \ 'git-write-tree should be able to write an empty tree.' \ 'tree=$(git-write-tree)' If you supply three parameters the first will be taken to be a prerequisite; see the test_set_prereq and test_have_prereq documentation below: test_expect_success TTY 'git --paginate rev-list uses a pager' \ ' ... ' You can also supply a comma-separated list of prerequisites, in the rare case where your test depends on more than one: test_expect_success PERL,PYTHON 'yo dawg' \ ' test $(perl -E 'print eval "1 +" . qx[python -c "print 2"]') == "4" ' - test_expect_failure [<prereq>] <message> <script> This is NOT the opposite of test_expect_success, but is used to mark a test that demonstrates a known breakage. Unlike the usual test_expect_success tests, which say "ok" on success and "FAIL" on failure, this will say "FIXED" on success and "still broken" on failure. Failures from these tests won't cause -i (immediate) to stop. Like test_expect_success this function can optionally use a three argument invocation with a prerequisite as the first argument. - test_debug <script> This takes a single argument, <script>, and evaluates it only when the test script is started with --debug command line argument. This is primarily meant for use during the development of a new test script. - test_done Your test script must have test_done at the end. Its purpose is to summarize successes and failures in the test script and exit with an appropriate error code. - test_tick Make commit and tag names consistent by setting the author and committer times to defined state. Subsequent calls will advance the times by a fixed amount. - test_commit <message> [<filename> [<contents>]] Creates a commit with the given message, committing the given file with the given contents (default for both is to reuse the message string), and adds a tag (again reusing the message string as name). Calls test_tick to make the SHA-1s reproducible. - test_merge <message> <commit-or-tag> Merges the given rev using the given message. Like test_commit, creates a tag and calls test_tick before committing. - test_set_prereq <prereq> Set a test prerequisite to be used later with test_have_prereq. The test-lib will set some prerequisites for you, see the "Prerequisites" section below for a full list of these. Others you can set yourself and use later with either test_have_prereq directly, or the three argument invocation of test_expect_success and test_expect_failure. - test_have_prereq <prereq> Check if we have a prerequisite previously set with test_set_prereq. The most common use of this directly is to skip all the tests if we don't have some essential prerequisite: if ! test_have_prereq PERL then skip_all='skipping perl interface tests, perl not available' test_done fi - test_external [<prereq>] <message> <external> <script> Execute a <script> with an <external> interpreter (like perl). This was added for tests like t9700-perl-git.sh which do most of their work in an external test script. test_external \ 'GitwebCache::*FileCache*' \ "$PERL_PATH" "$TEST_DIRECTORY"/t9503/test_cache_interface.pl If the test is outputting its own TAP you should set the test_external_has_tap variable somewhere before calling the first test_external* function. See t9700-perl-git.sh for an example. # The external test will outputs its own plan test_external_has_tap=1 - test_external_without_stderr [<prereq>] <message> <external> <script> Like test_external but fail if there's any output on stderr, instead of checking the exit code. test_external_without_stderr \ 'Perl API' \ "$PERL_PATH" "$TEST_DIRECTORY"/t9700/test.pl - test_expect_code <exit-code> <command> Run a command and ensure that it exits with the given exit code. For example: test_expect_success 'Merge with d/f conflicts' ' test_expect_code 1 git merge "merge msg" B master ' - test_must_fail <git-command> Run a git command and ensure it fails in a controlled way. Use this instead of "! <git-command>". When git-command dies due to a segfault, test_must_fail diagnoses it as an error; "! <git-command>" treats it as just another expected failure, which would let such a bug go unnoticed. - test_might_fail <git-command> Similar to test_must_fail, but tolerate success, too. Use this instead of "<git-command> || :" to catch failures due to segv. - test_cmp <expected> <actual> Check whether the content of the <actual> file matches the <expected> file. This behaves like "cmp" but produces more helpful output when the test is run with "-v" option. - test_line_count (= | -lt | -ge | ...) <length> <file> Check whether a file has the length it is expected to. - test_path_is_file <path> [<diagnosis>] test_path_is_dir <path> [<diagnosis>] test_path_is_missing <path> [<diagnosis>] Check if the named path is a file, if the named path is a directory, or if the named path does not exist, respectively, and fail otherwise, showing the <diagnosis> text. - test_when_finished <script> Prepend <script> to a list of commands to run to clean up at the end of the current test. If some clean-up command fails, the test will not pass. Example: test_expect_success 'branch pointing to non-commit' ' git rev-parse HEAD^{tree} >.git/refs/heads/invalid && test_when_finished "git update-ref -d refs/heads/invalid" && ... ' - test_pause This command is useful for writing and debugging tests and must be removed before submitting. It halts the execution of the test and spawns a shell in the trash directory. Exit the shell to continue the test. Example: test_expect_success 'test' ' git do-something >actual && test_pause && test_cmp expected actual ' - test_ln_s_add <path1> <path2> This function helps systems whose filesystem does not support symbolic links. Use it to add a symbolic link entry to the index when it is not important that the file system entry is a symbolic link, i.e., instead of the sequence ln -s foo bar && git add bar Sometimes it is possible to split a test in a part that does not need the symbolic link in the file system and a part that does; then only the latter part need be protected by a SYMLINKS prerequisite (see below). Prerequisites ------------- These are the prerequisites that the test library predefines with test_have_prereq. See the prereq argument to the test_* functions in the "Test harness library" section above and the "test_have_prereq" function for how to use these, and "test_set_prereq" for how to define your own. - PERL & PYTHON Git wasn't compiled with NO_PERL=YesPlease or NO_PYTHON=YesPlease. Wrap any tests that need Perl or Python in these. - POSIXPERM The filesystem supports POSIX style permission bits. - BSLASHPSPEC Backslashes in pathspec are not directory separators. This is not set on Windows. See 6fd1106a for details. - EXECKEEPSPID The process retains the same pid across exec(2). See fb9a2bea for details. - PIPE The filesystem we're on supports creation of FIFOs (named pipes) via mkfifo(1). - SYMLINKS The filesystem we're on supports symbolic links. E.g. a FAT filesystem doesn't support these. See 704a3143 for details. - SANITY Test is not run by root user, and an attempt to write to an unwritable file is expected to fail correctly. - LIBPCRE Git was compiled with USE_LIBPCRE=YesPlease. Wrap any tests that use git-grep --perl-regexp or git-grep -P in these. - CASE_INSENSITIVE_FS Test is run on a case insensitive file system. - UTF8_NFD_TO_NFC Test is run on a filesystem which converts decomposed utf-8 (nfd) to precomposed utf-8 (nfc). Tips for Writing Tests ---------------------- As with any programming projects, existing programs are the best source of the information. However, do _not_ emulate t0000-basic.sh when writing your tests. The test is special in that it tries to validate the very core of GIT. For example, it knows that there will be 256 subdirectories under .git/objects/, and it knows that the object ID of an empty tree is a certain 40-byte string. This is deliberately done so in t0000-basic.sh because the things the very basic core test tries to achieve is to serve as a basis for people who are changing the GIT internal drastically. For these people, after making certain changes, not seeing failures from the basic test _is_ a failure. And such drastic changes to the core GIT that even changes these otherwise supposedly stable object IDs should be accompanied by an update to t0000-basic.sh. However, other tests that simply rely on basic parts of the core GIT working properly should not have that level of intimate knowledge of the core GIT internals. If all the test scripts hardcoded the object IDs like t0000-basic.sh does, that defeats the purpose of t0000-basic.sh, which is to isolate that level of validation in one place. Your test also ends up needing updating when such a change to the internal happens, so do _not_ do it and leave the low level of validation to t0000-basic.sh. Test coverage ------------- You can use the coverage tests to find code paths that are not being used or properly exercised yet. To do that, run the coverage target at the top-level (not in the t/ directory): make coverage That'll compile Git with GCC's coverage arguments, and generate a test report with gcov after the tests finish. Running the coverage tests can take a while, since running the tests in parallel is incompatible with GCC's coverage mode. After the tests have run you can generate a list of untested functions: make coverage-untested-functions You can also generate a detailed per-file HTML report using the Devel::Cover module. To install it do: # On Debian or Ubuntu: sudo aptitude install libdevel-cover-perl # From the CPAN with cpanminus curl -L http://cpanmin.us | perl - --sudo --self-upgrade cpanm --sudo Devel::Cover Then, at the top-level: make cover_db_html That'll generate a detailed cover report in the "cover_db_html" directory, which you can then copy to a webserver, or inspect locally in a browser.