t / READMEon commit Merge branch 'ab/git-svn-get-record-typofix' (a500a9c)
   1Core GIT Tests
   2==============
   3
   4This directory holds many test scripts for core GIT tools.  The
   5first part of this short document describes how to run the tests
   6and read their output.
   7
   8When fixing the tools or adding enhancements, you are strongly
   9encouraged to add tests in this directory to cover what you are
  10trying to fix or enhance.  The later part of this short document
  11describes how your test scripts should be organized.
  12
  13
  14Running Tests
  15-------------
  16
  17The easiest way to run tests is to say "make".  This runs all
  18the tests.
  19
  20    *** t0000-basic.sh ***
  21    ok 1 - .git/objects should be empty after git init in an empty repo.
  22    ok 2 - .git/objects should have 3 subdirectories.
  23    ok 3 - success is reported like this
  24    ...
  25    ok 43 - very long name in the index handled sanely
  26    # fixed 1 known breakage(s)
  27    # still have 1 known breakage(s)
  28    # passed all remaining 42 test(s)
  29    1..43
  30    *** t0001-init.sh ***
  31    ok 1 - plain
  32    ok 2 - plain with GIT_WORK_TREE
  33    ok 3 - plain bare
  34
  35Since the tests all output TAP (see http://testanything.org) they can
  36be run with any TAP harness. Here's an example of parallel testing
  37powered by a recent version of prove(1):
  38
  39    $ prove --timer --jobs 15 ./t[0-9]*.sh
  40    [19:17:33] ./t0005-signals.sh ................................... ok       36 ms
  41    [19:17:33] ./t0022-crlf-rename.sh ............................... ok       69 ms
  42    [19:17:33] ./t0024-crlf-archive.sh .............................. ok      154 ms
  43    [19:17:33] ./t0004-unwritable.sh ................................ ok      289 ms
  44    [19:17:33] ./t0002-gitfile.sh ................................... ok      480 ms
  45    ===(     102;0  25/?  6/?  5/?  16/?  1/?  4/?  2/?  1/?  3/?  1... )===
  46
  47prove and other harnesses come with a lot of useful options. The
  48--state option in particular is very useful:
  49
  50    # Repeat until no more failures
  51    $ prove -j 15 --state=failed,save ./t[0-9]*.sh
  52
  53You can give DEFAULT_TEST_TARGET=prove on the make command (or define it
  54in config.mak) to cause "make test" to run tests under prove.
  55GIT_PROVE_OPTS can be used to pass additional options, e.g.
  56
  57    $ make DEFAULT_TEST_TARGET=prove GIT_PROVE_OPTS='--timer --jobs 16' test
  58
  59You can also run each test individually from command line, like this:
  60
  61    $ sh ./t3010-ls-files-killed-modified.sh
  62    ok 1 - git update-index --add to add various paths.
  63    ok 2 - git ls-files -k to show killed files.
  64    ok 3 - validate git ls-files -k output.
  65    ok 4 - git ls-files -m to show modified files.
  66    ok 5 - validate git ls-files -m output.
  67    # passed all 5 test(s)
  68    1..5
  69
  70You can pass --verbose (or -v), --debug (or -d), and --immediate
  71(or -i) command line argument to the test, or by setting GIT_TEST_OPTS
  72appropriately before running "make".
  73
  74-v::
  75--verbose::
  76        This makes the test more verbose.  Specifically, the
  77        command being run and their output if any are also
  78        output.
  79
  80--verbose-only=<pattern>::
  81        Like --verbose, but the effect is limited to tests with
  82        numbers matching <pattern>.  The number matched against is
  83        simply the running count of the test within the file.
  84
  85-x::
  86        Turn on shell tracing (i.e., `set -x`) during the tests
  87        themselves. Implies `--verbose`.
  88        Ignored in test scripts that set the variable 'test_untraceable'
  89        to a non-empty value, unless it's run with a Bash version
  90        supporting BASH_XTRACEFD, i.e. v4.1 or later.
  91
  92-d::
  93--debug::
  94        This may help the person who is developing a new test.
  95        It causes the command defined with test_debug to run.
  96        The "trash" directory (used to store all temporary data
  97        during testing) is not deleted even if there are no
  98        failed tests so that you can inspect its contents after
  99        the test finished.
 100
 101-i::
 102--immediate::
 103        This causes the test to immediately exit upon the first
 104        failed test. Cleanup commands requested with
 105        test_when_finished are not executed if the test failed,
 106        in order to keep the state for inspection by the tester
 107        to diagnose the bug.
 108
 109-l::
 110--long-tests::
 111        This causes additional long-running tests to be run (where
 112        available), for more exhaustive testing.
 113
 114-r::
 115--run=<test-selector>::
 116        Run only the subset of tests indicated by
 117        <test-selector>.  See section "Skipping Tests" below for
 118        <test-selector> syntax.
 119
 120--valgrind=<tool>::
 121        Execute all Git binaries under valgrind tool <tool> and exit
 122        with status 126 on errors (just like regular tests, this will
 123        only stop the test script when running under -i).
 124
 125        Since it makes no sense to run the tests with --valgrind and
 126        not see any output, this option implies --verbose.  For
 127        convenience, it also implies --tee.
 128
 129        <tool> defaults to 'memcheck', just like valgrind itself.
 130        Other particularly useful choices include 'helgrind' and
 131        'drd', but you may use any tool recognized by your valgrind
 132        installation.
 133
 134        As a special case, <tool> can be 'memcheck-fast', which uses
 135        memcheck but disables --track-origins.  Use this if you are
 136        running tests in bulk, to see if there are _any_ memory
 137        issues.
 138
 139        Note that memcheck is run with the option --leak-check=no,
 140        as the git process is short-lived and some errors are not
 141        interesting. In order to run a single command under the same
 142        conditions manually, you should set GIT_VALGRIND to point to
 143        the 't/valgrind/' directory and use the commands under
 144        't/valgrind/bin/'.
 145
 146--valgrind-only=<pattern>::
 147        Like --valgrind, but the effect is limited to tests with
 148        numbers matching <pattern>.  The number matched against is
 149        simply the running count of the test within the file.
 150
 151--tee::
 152        In addition to printing the test output to the terminal,
 153        write it to files named 't/test-results/$TEST_NAME.out'.
 154        As the names depend on the tests' file names, it is safe to
 155        run the tests with this option in parallel.
 156
 157--verbose-log::
 158        Write verbose output to the same logfile as `--tee`, but do
 159        _not_ write it to stdout. Unlike `--tee --verbose`, this option
 160        is safe to use when stdout is being consumed by a TAP parser
 161        like `prove`. Implies `--tee` and `--verbose`.
 162
 163--with-dashes::
 164        By default tests are run without dashed forms of
 165        commands (like git-commit) in the PATH (it only uses
 166        wrappers from ../bin-wrappers).  Use this option to include
 167        the build directory (..) in the PATH, which contains all
 168        the dashed forms of commands.  This option is currently
 169        implied by other options like --valgrind and
 170        GIT_TEST_INSTALLED.
 171
 172--root=<directory>::
 173        Create "trash" directories used to store all temporary data during
 174        testing under <directory>, instead of the t/ directory.
 175        Using this option with a RAM-based filesystem (such as tmpfs)
 176        can massively speed up the test suite.
 177
 178--chain-lint::
 179--no-chain-lint::
 180        If --chain-lint is enabled, the test harness will check each
 181        test to make sure that it properly "&&-chains" all commands (so
 182        that a failure in the middle does not go unnoticed by the final
 183        exit code of the test). This check is performed in addition to
 184        running the tests themselves. You may also enable or disable
 185        this feature by setting the GIT_TEST_CHAIN_LINT environment
 186        variable to "1" or "0", respectively.
 187
 188You can also set the GIT_TEST_INSTALLED environment variable to
 189the bindir of an existing git installation to test that installation.
 190You still need to have built this git sandbox, from which various
 191test-* support programs, templates, and perl libraries are used.
 192If your installed git is incomplete, it will silently test parts of
 193your built version instead.
 194
 195When using GIT_TEST_INSTALLED, you can also set GIT_TEST_EXEC_PATH to
 196override the location of the dashed-form subcommands (what
 197GIT_EXEC_PATH would be used for during normal operation).
 198GIT_TEST_EXEC_PATH defaults to `$GIT_TEST_INSTALLED/git --exec-path`.
 199
 200
 201Skipping Tests
 202--------------
 203
 204In some environments, certain tests have no way of succeeding
 205due to platform limitation, such as lack of 'unzip' program, or
 206filesystem that do not allow arbitrary sequence of non-NUL bytes
 207as pathnames.
 208
 209You should be able to say something like
 210
 211    $ GIT_SKIP_TESTS=t9200.8 sh ./t9200-git-cvsexport-commit.sh
 212
 213and even:
 214
 215    $ GIT_SKIP_TESTS='t[0-4]??? t91?? t9200.8' make
 216
 217to omit such tests.  The value of the environment variable is a
 218SP separated list of patterns that tells which tests to skip,
 219and either can match the "t[0-9]{4}" part to skip the whole
 220test, or t[0-9]{4} followed by ".$number" to say which
 221particular test to skip.
 222
 223For an individual test suite --run could be used to specify that
 224only some tests should be run or that some tests should be
 225excluded from a run.
 226
 227The argument for --run is a list of individual test numbers or
 228ranges with an optional negation prefix that define what tests in
 229a test suite to include in the run.  A range is two numbers
 230separated with a dash and matches a range of tests with both ends
 231been included.  You may omit the first or the second number to
 232mean "from the first test" or "up to the very last test"
 233respectively.
 234
 235Optional prefix of '!' means that the test or a range of tests
 236should be excluded from the run.
 237
 238If --run starts with an unprefixed number or range the initial
 239set of tests to run is empty. If the first item starts with '!'
 240all the tests are added to the initial set.  After initial set is
 241determined every test number or range is added or excluded from
 242the set one by one, from left to right.
 243
 244Individual numbers or ranges could be separated either by a space
 245or a comma.
 246
 247For example, to run only tests up to a specific test (21), one
 248could do this:
 249
 250    $ sh ./t9200-git-cvsexport-commit.sh --run='1-21'
 251
 252or this:
 253
 254    $ sh ./t9200-git-cvsexport-commit.sh --run='-21'
 255
 256Common case is to run several setup tests (1, 2, 3) and then a
 257specific test (21) that relies on that setup:
 258
 259    $ sh ./t9200-git-cvsexport-commit.sh --run='1 2 3 21'
 260
 261or:
 262
 263    $ sh ./t9200-git-cvsexport-commit.sh --run=1,2,3,21
 264
 265or:
 266
 267    $ sh ./t9200-git-cvsexport-commit.sh --run='-3 21'
 268
 269As noted above, the test set is built by going through the items
 270from left to right, so this:
 271
 272    $ sh ./t9200-git-cvsexport-commit.sh --run='1-4 !3'
 273
 274will run tests 1, 2, and 4.  Items that come later have higher
 275precedence.  It means that this:
 276
 277    $ sh ./t9200-git-cvsexport-commit.sh --run='!3 1-4'
 278
 279would just run tests from 1 to 4, including 3.
 280
 281You may use negation with ranges.  The following will run all
 282test in the test suite except from 7 up to 11:
 283
 284    $ sh ./t9200-git-cvsexport-commit.sh --run='!7-11'
 285
 286Some tests in a test suite rely on the previous tests performing
 287certain actions, specifically some tests are designated as
 288"setup" test, so you cannot _arbitrarily_ disable one test and
 289expect the rest to function correctly.
 290
 291--run is mostly useful when you want to focus on a specific test
 292and know what setup is needed for it.  Or when you want to run
 293everything up to a certain test.
 294
 295
 296Naming Tests
 297------------
 298
 299The test files are named as:
 300
 301        tNNNN-commandname-details.sh
 302
 303where N is a decimal digit.
 304
 305First digit tells the family:
 306
 307        0 - the absolute basics and global stuff
 308        1 - the basic commands concerning database
 309        2 - the basic commands concerning the working tree
 310        3 - the other basic commands (e.g. ls-files)
 311        4 - the diff commands
 312        5 - the pull and exporting commands
 313        6 - the revision tree commands (even e.g. merge-base)
 314        7 - the porcelainish commands concerning the working tree
 315        8 - the porcelainish commands concerning forensics
 316        9 - the git tools
 317
 318Second digit tells the particular command we are testing.
 319
 320Third digit (optionally) tells the particular switch or group of switches
 321we are testing.
 322
 323If you create files under t/ directory (i.e. here) that is not
 324the top-level test script, never name the file to match the above
 325pattern.  The Makefile here considers all such files as the
 326top-level test script and tries to run all of them.  Care is
 327especially needed if you are creating a common test library
 328file, similar to test-lib.sh, because such a library file may
 329not be suitable for standalone execution.
 330
 331
 332Writing Tests
 333-------------
 334
 335The test script is written as a shell script.  It should start
 336with the standard "#!/bin/sh", and an
 337assignment to variable 'test_description', like this:
 338
 339        #!/bin/sh
 340
 341        test_description='xxx test (option --frotz)
 342
 343        This test registers the following structure in the cache
 344        and tries to run git-ls-files with option --frotz.'
 345
 346
 347Source 'test-lib.sh'
 348--------------------
 349
 350After assigning test_description, the test script should source
 351test-lib.sh like this:
 352
 353        . ./test-lib.sh
 354
 355This test harness library does the following things:
 356
 357 - If the script is invoked with command line argument --help
 358   (or -h), it shows the test_description and exits.
 359
 360 - Creates an empty test directory with an empty .git/objects database
 361   and chdir(2) into it.  This directory is 't/trash
 362   directory.$test_name_without_dotsh', with t/ subject to change by
 363   the --root option documented above.
 364
 365 - Defines standard test helper functions for your scripts to
 366   use.  These functions are designed to make all scripts behave
 367   consistently when command line arguments --verbose (or -v),
 368   --debug (or -d), and --immediate (or -i) is given.
 369
 370Do's, don'ts & things to keep in mind
 371-------------------------------------
 372
 373Here are a few examples of things you probably should and shouldn't do
 374when writing tests.
 375
 376Do:
 377
 378 - Put all code inside test_expect_success and other assertions.
 379
 380   Even code that isn't a test per se, but merely some setup code
 381   should be inside a test assertion.
 382
 383 - Chain your test assertions
 384
 385   Write test code like this:
 386
 387        git merge foo &&
 388        git push bar &&
 389        test ...
 390
 391   Instead of:
 392
 393        git merge hla
 394        git push gh
 395        test ...
 396
 397   That way all of the commands in your tests will succeed or fail. If
 398   you must ignore the return value of something, consider using a
 399   helper function (e.g. use sane_unset instead of unset, in order
 400   to avoid unportable return value for unsetting a variable that was
 401   already unset), or prepending the command with test_might_fail or
 402   test_must_fail.
 403
 404 - Check the test coverage for your tests. See the "Test coverage"
 405   below.
 406
 407   Don't blindly follow test coverage metrics; if a new function you added
 408   doesn't have any coverage, then you're probably doing something wrong,
 409   but having 100% coverage doesn't necessarily mean that you tested
 410   everything.
 411
 412   Tests that are likely to smoke out future regressions are better
 413   than tests that just inflate the coverage metrics.
 414
 415 - When a test checks for an absolute path that a git command generated,
 416   construct the expected value using $(pwd) rather than $PWD,
 417   $TEST_DIRECTORY, or $TRASH_DIRECTORY. It makes a difference on
 418   Windows, where the shell (MSYS bash) mangles absolute path names.
 419   For details, see the commit message of 4114156ae9.
 420
 421Don't:
 422
 423 - exit() within a <script> part.
 424
 425   The harness will catch this as a programming error of the test.
 426   Use test_done instead if you need to stop the tests early (see
 427   "Skipping tests" below).
 428
 429 - use '! git cmd' when you want to make sure the git command exits
 430   with failure in a controlled way by calling "die()".  Instead,
 431   use 'test_must_fail git cmd'.  This will signal a failure if git
 432   dies in an unexpected way (e.g. segfault).
 433
 434   On the other hand, don't use test_must_fail for running regular
 435   platform commands; just use '! cmd'.  We are not in the business
 436   of verifying that the world given to us sanely works.
 437
 438 - use perl without spelling it as "$PERL_PATH". This is to help our
 439   friends on Windows where the platform Perl often adds CR before
 440   the end of line, and they bundle Git with a version of Perl that
 441   does not do so, whose path is specified with $PERL_PATH. Note that we
 442   provide a "perl" function which uses $PERL_PATH under the hood, so
 443   you do not need to worry when simply running perl in the test scripts
 444   (but you do, for example, on a shebang line or in a sub script
 445   created via "write_script").
 446
 447 - use sh without spelling it as "$SHELL_PATH", when the script can
 448   be misinterpreted by broken platform shell (e.g. Solaris).
 449
 450 - chdir around in tests.  It is not sufficient to chdir to
 451   somewhere and then chdir back to the original location later in
 452   the test, as any intermediate step can fail and abort the test,
 453   causing the next test to start in an unexpected directory.  Do so
 454   inside a subshell if necessary.
 455
 456 - save and verify the standard error of compound commands, i.e. group
 457   commands, subshells, and shell functions (except test helper
 458   functions like 'test_must_fail') like this:
 459
 460     ( cd dir && git cmd ) 2>error &&
 461     test_cmp expect error
 462
 463   When running the test with '-x' tracing, then the trace of commands
 464   executed in the compound command will be included in standard error
 465   as well, quite possibly throwing off the subsequent checks examining
 466   the output.  Instead, save only the relevant git command's standard
 467   error:
 468
 469     ( cd dir && git cmd 2>../error ) &&
 470     test_cmp expect error
 471
 472 - Break the TAP output
 473
 474   The raw output from your test may be interpreted by a TAP harness. TAP
 475   harnesses will ignore everything they don't know about, but don't step
 476   on their toes in these areas:
 477
 478   - Don't print lines like "$x..$y" where $x and $y are integers.
 479
 480   - Don't print lines that begin with "ok" or "not ok".
 481
 482   TAP harnesses expect a line that begins with either "ok" and "not
 483   ok" to signal a test passed or failed (and our harness already
 484   produces such lines), so your script shouldn't emit such lines to
 485   their output.
 486
 487   You can glean some further possible issues from the TAP grammar
 488   (see https://metacpan.org/pod/TAP::Parser::Grammar#TAP-GRAMMAR)
 489   but the best indication is to just run the tests with prove(1),
 490   it'll complain if anything is amiss.
 491
 492Keep in mind:
 493
 494 - Inside the <script> part, the standard output and standard error
 495   streams are discarded, and the test harness only reports "ok" or
 496   "not ok" to the end user running the tests. Under --verbose, they
 497   are shown to help debugging the tests.
 498
 499
 500Skipping tests
 501--------------
 502
 503If you need to skip tests you should do so by using the three-arg form
 504of the test_* functions (see the "Test harness library" section
 505below), e.g.:
 506
 507    test_expect_success PERL 'I need Perl' '
 508        perl -e "hlagh() if unf_unf()"
 509    '
 510
 511The advantage of skipping tests like this is that platforms that don't
 512have the PERL and other optional dependencies get an indication of how
 513many tests they're missing.
 514
 515If the test code is too hairy for that (i.e. does a lot of setup work
 516outside test assertions) you can also skip all remaining tests by
 517setting skip_all and immediately call test_done:
 518
 519        if ! test_have_prereq PERL
 520        then
 521            skip_all='skipping perl interface tests, perl not available'
 522            test_done
 523        fi
 524
 525The string you give to skip_all will be used as an explanation for why
 526the test was skipped.
 527
 528End with test_done
 529------------------
 530
 531Your script will be a sequence of tests, using helper functions
 532from the test harness library.  At the end of the script, call
 533'test_done'.
 534
 535
 536Test harness library
 537--------------------
 538
 539There are a handful helper functions defined in the test harness
 540library for your script to use.
 541
 542 - test_expect_success [<prereq>] <message> <script>
 543
 544   Usually takes two strings as parameters, and evaluates the
 545   <script>.  If it yields success, test is considered
 546   successful.  <message> should state what it is testing.
 547
 548   Example:
 549
 550        test_expect_success \
 551            'git-write-tree should be able to write an empty tree.' \
 552            'tree=$(git-write-tree)'
 553
 554   If you supply three parameters the first will be taken to be a
 555   prerequisite; see the test_set_prereq and test_have_prereq
 556   documentation below:
 557
 558        test_expect_success TTY 'git --paginate rev-list uses a pager' \
 559            ' ... '
 560
 561   You can also supply a comma-separated list of prerequisites, in the
 562   rare case where your test depends on more than one:
 563
 564        test_expect_success PERL,PYTHON 'yo dawg' \
 565            ' test $(perl -E 'print eval "1 +" . qx[python -c "print 2"]') == "4" '
 566
 567 - test_expect_failure [<prereq>] <message> <script>
 568
 569   This is NOT the opposite of test_expect_success, but is used
 570   to mark a test that demonstrates a known breakage.  Unlike
 571   the usual test_expect_success tests, which say "ok" on
 572   success and "FAIL" on failure, this will say "FIXED" on
 573   success and "still broken" on failure.  Failures from these
 574   tests won't cause -i (immediate) to stop.
 575
 576   Like test_expect_success this function can optionally use a three
 577   argument invocation with a prerequisite as the first argument.
 578
 579 - test_debug <script>
 580
 581   This takes a single argument, <script>, and evaluates it only
 582   when the test script is started with --debug command line
 583   argument.  This is primarily meant for use during the
 584   development of a new test script.
 585
 586 - debug <git-command>
 587
 588   Run a git command inside a debugger. This is primarily meant for
 589   use when debugging a failing test script.
 590
 591 - test_done
 592
 593   Your test script must have test_done at the end.  Its purpose
 594   is to summarize successes and failures in the test script and
 595   exit with an appropriate error code.
 596
 597 - test_tick
 598
 599   Make commit and tag names consistent by setting the author and
 600   committer times to defined state.  Subsequent calls will
 601   advance the times by a fixed amount.
 602
 603 - test_commit <message> [<filename> [<contents>]]
 604
 605   Creates a commit with the given message, committing the given
 606   file with the given contents (default for both is to reuse the
 607   message string), and adds a tag (again reusing the message
 608   string as name).  Calls test_tick to make the SHA-1s
 609   reproducible.
 610
 611 - test_merge <message> <commit-or-tag>
 612
 613   Merges the given rev using the given message.  Like test_commit,
 614   creates a tag and calls test_tick before committing.
 615
 616 - test_set_prereq <prereq>
 617
 618   Set a test prerequisite to be used later with test_have_prereq. The
 619   test-lib will set some prerequisites for you, see the
 620   "Prerequisites" section below for a full list of these.
 621
 622   Others you can set yourself and use later with either
 623   test_have_prereq directly, or the three argument invocation of
 624   test_expect_success and test_expect_failure.
 625
 626 - test_have_prereq <prereq>
 627
 628   Check if we have a prerequisite previously set with test_set_prereq.
 629   The most common way to use this explicitly (as opposed to the
 630   implicit use when an argument is passed to test_expect_*) is to skip
 631   all the tests at the start of the test script if we don't have some
 632   essential prerequisite:
 633
 634        if ! test_have_prereq PERL
 635        then
 636            skip_all='skipping perl interface tests, perl not available'
 637            test_done
 638        fi
 639
 640 - test_external [<prereq>] <message> <external> <script>
 641
 642   Execute a <script> with an <external> interpreter (like perl). This
 643   was added for tests like t9700-perl-git.sh which do most of their
 644   work in an external test script.
 645
 646        test_external \
 647            'GitwebCache::*FileCache*' \
 648            perl "$TEST_DIRECTORY"/t9503/test_cache_interface.pl
 649
 650   If the test is outputting its own TAP you should set the
 651   test_external_has_tap variable somewhere before calling the first
 652   test_external* function. See t9700-perl-git.sh for an example.
 653
 654        # The external test will outputs its own plan
 655        test_external_has_tap=1
 656
 657 - test_external_without_stderr [<prereq>] <message> <external> <script>
 658
 659   Like test_external but fail if there's any output on stderr,
 660   instead of checking the exit code.
 661
 662        test_external_without_stderr \
 663            'Perl API' \
 664            perl "$TEST_DIRECTORY"/t9700/test.pl
 665
 666 - test_expect_code <exit-code> <command>
 667
 668   Run a command and ensure that it exits with the given exit code.
 669   For example:
 670
 671        test_expect_success 'Merge with d/f conflicts' '
 672                test_expect_code 1 git merge "merge msg" B master
 673        '
 674
 675 - test_must_fail [<options>] <git-command>
 676
 677   Run a git command and ensure it fails in a controlled way.  Use
 678   this instead of "! <git-command>".  When git-command dies due to a
 679   segfault, test_must_fail diagnoses it as an error; "! <git-command>"
 680   treats it as just another expected failure, which would let such a
 681   bug go unnoticed.
 682
 683   Accepts the following options:
 684
 685     ok=<signal-name>[,<...>]:
 686       Don't treat an exit caused by the given signal as error.
 687       Multiple signals can be specified as a comma separated list.
 688       Currently recognized signal names are: sigpipe, success.
 689       (Don't use 'success', use 'test_might_fail' instead.)
 690
 691 - test_might_fail [<options>] <git-command>
 692
 693   Similar to test_must_fail, but tolerate success, too.  Use this
 694   instead of "<git-command> || :" to catch failures due to segv.
 695
 696   Accepts the same options as test_must_fail.
 697
 698 - test_cmp <expected> <actual>
 699
 700   Check whether the content of the <actual> file matches the
 701   <expected> file.  This behaves like "cmp" but produces more
 702   helpful output when the test is run with "-v" option.
 703
 704 - test_cmp_rev <expected> <actual>
 705
 706   Check whether the <expected> rev points to the same commit as the
 707   <actual> rev.
 708
 709 - test_line_count (= | -lt | -ge | ...) <length> <file>
 710
 711   Check whether a file has the length it is expected to.
 712
 713 - test_path_is_file <path> [<diagnosis>]
 714   test_path_is_dir <path> [<diagnosis>]
 715   test_path_is_missing <path> [<diagnosis>]
 716
 717   Check if the named path is a file, if the named path is a
 718   directory, or if the named path does not exist, respectively,
 719   and fail otherwise, showing the <diagnosis> text.
 720
 721 - test_when_finished <script>
 722
 723   Prepend <script> to a list of commands to run to clean up
 724   at the end of the current test.  If some clean-up command
 725   fails, the test will not pass.
 726
 727   Example:
 728
 729        test_expect_success 'branch pointing to non-commit' '
 730                git rev-parse HEAD^{tree} >.git/refs/heads/invalid &&
 731                test_when_finished "git update-ref -d refs/heads/invalid" &&
 732                ...
 733        '
 734
 735 - test_write_lines <lines>
 736
 737   Write <lines> on standard output, one line per argument.
 738   Useful to prepare multi-line files in a compact form.
 739
 740   Example:
 741
 742        test_write_lines a b c d e f g >foo
 743
 744   Is a more compact equivalent of:
 745        cat >foo <<-EOF
 746        a
 747        b
 748        c
 749        d
 750        e
 751        f
 752        g
 753        EOF
 754
 755
 756 - test_pause
 757
 758        This command is useful for writing and debugging tests and must be
 759        removed before submitting. It halts the execution of the test and
 760        spawns a shell in the trash directory. Exit the shell to continue
 761        the test. Example:
 762
 763        test_expect_success 'test' '
 764                git do-something >actual &&
 765                test_pause &&
 766                test_cmp expected actual
 767        '
 768
 769 - test_ln_s_add <path1> <path2>
 770
 771   This function helps systems whose filesystem does not support symbolic
 772   links. Use it to add a symbolic link entry to the index when it is not
 773   important that the file system entry is a symbolic link, i.e., instead
 774   of the sequence
 775
 776        ln -s foo bar &&
 777        git add bar
 778
 779   Sometimes it is possible to split a test in a part that does not need
 780   the symbolic link in the file system and a part that does; then only
 781   the latter part need be protected by a SYMLINKS prerequisite (see below).
 782
 783Prerequisites
 784-------------
 785
 786These are the prerequisites that the test library predefines with
 787test_have_prereq.
 788
 789See the prereq argument to the test_* functions in the "Test harness
 790library" section above and the "test_have_prereq" function for how to
 791use these, and "test_set_prereq" for how to define your own.
 792
 793 - PYTHON
 794
 795   Git wasn't compiled with NO_PYTHON=YesPlease. Wrap any tests that
 796   need Python with this.
 797
 798 - PERL
 799
 800   Git wasn't compiled with NO_PERL=YesPlease.
 801
 802   Even without the PERL prerequisite, tests can assume there is a
 803   usable perl interpreter at $PERL_PATH, though it need not be
 804   particularly modern.
 805
 806 - POSIXPERM
 807
 808   The filesystem supports POSIX style permission bits.
 809
 810 - BSLASHPSPEC
 811
 812   Backslashes in pathspec are not directory separators. This is not
 813   set on Windows. See 6fd1106a for details.
 814
 815 - EXECKEEPSPID
 816
 817   The process retains the same pid across exec(2). See fb9a2bea for
 818   details.
 819
 820 - PIPE
 821
 822   The filesystem we're on supports creation of FIFOs (named pipes)
 823   via mkfifo(1).
 824
 825 - SYMLINKS
 826
 827   The filesystem we're on supports symbolic links. E.g. a FAT
 828   filesystem doesn't support these. See 704a3143 for details.
 829
 830 - SANITY
 831
 832   Test is not run by root user, and an attempt to write to an
 833   unwritable file is expected to fail correctly.
 834
 835 - PCRE
 836
 837   Git was compiled with support for PCRE. Wrap any tests
 838   that use git-grep --perl-regexp or git-grep -P in these.
 839
 840 - LIBPCRE1
 841
 842   Git was compiled with PCRE v1 support via
 843   USE_LIBPCRE1=YesPlease. Wrap any PCRE using tests that for some
 844   reason need v1 of the PCRE library instead of v2 in these.
 845
 846 - LIBPCRE2
 847
 848   Git was compiled with PCRE v2 support via
 849   USE_LIBPCRE2=YesPlease. Wrap any PCRE using tests that for some
 850   reason need v2 of the PCRE library instead of v1 in these.
 851
 852 - CASE_INSENSITIVE_FS
 853
 854   Test is run on a case insensitive file system.
 855
 856 - UTF8_NFD_TO_NFC
 857
 858   Test is run on a filesystem which converts decomposed utf-8 (nfd)
 859   to precomposed utf-8 (nfc).
 860
 861 - PTHREADS
 862
 863   Git wasn't compiled with NO_PTHREADS=YesPlease.
 864
 865Tips for Writing Tests
 866----------------------
 867
 868As with any programming projects, existing programs are the best
 869source of the information.  However, do _not_ emulate
 870t0000-basic.sh when writing your tests.  The test is special in
 871that it tries to validate the very core of GIT.  For example, it
 872knows that there will be 256 subdirectories under .git/objects/,
 873and it knows that the object ID of an empty tree is a certain
 87440-byte string.  This is deliberately done so in t0000-basic.sh
 875because the things the very basic core test tries to achieve is
 876to serve as a basis for people who are changing the GIT internal
 877drastically.  For these people, after making certain changes,
 878not seeing failures from the basic test _is_ a failure.  And
 879such drastic changes to the core GIT that even changes these
 880otherwise supposedly stable object IDs should be accompanied by
 881an update to t0000-basic.sh.
 882
 883However, other tests that simply rely on basic parts of the core
 884GIT working properly should not have that level of intimate
 885knowledge of the core GIT internals.  If all the test scripts
 886hardcoded the object IDs like t0000-basic.sh does, that defeats
 887the purpose of t0000-basic.sh, which is to isolate that level of
 888validation in one place.  Your test also ends up needing
 889updating when such a change to the internal happens, so do _not_
 890do it and leave the low level of validation to t0000-basic.sh.
 891
 892Test coverage
 893-------------
 894
 895You can use the coverage tests to find code paths that are not being
 896used or properly exercised yet.
 897
 898To do that, run the coverage target at the top-level (not in the t/
 899directory):
 900
 901    make coverage
 902
 903That'll compile Git with GCC's coverage arguments, and generate a test
 904report with gcov after the tests finish. Running the coverage tests
 905can take a while, since running the tests in parallel is incompatible
 906with GCC's coverage mode.
 907
 908After the tests have run you can generate a list of untested
 909functions:
 910
 911    make coverage-untested-functions
 912
 913You can also generate a detailed per-file HTML report using the
 914Devel::Cover module. To install it do:
 915
 916   # On Debian or Ubuntu:
 917   sudo aptitude install libdevel-cover-perl
 918
 919   # From the CPAN with cpanminus
 920   curl -L http://cpanmin.us | perl - --sudo --self-upgrade
 921   cpanm --sudo Devel::Cover
 922
 923Then, at the top-level:
 924
 925    make cover_db_html
 926
 927That'll generate a detailed cover report in the "cover_db_html"
 928directory, which you can then copy to a webserver, or inspect locally
 929in a browser.