test-lib.sh: support -x option for shell-tracing
[git/git.git] / t / README
1 Core GIT Tests
2 ==============
3
4 This directory holds many test scripts for core GIT tools. The
5 first part of this short document describes how to run the tests
6 and read their output.
7
8 When fixing the tools or adding enhancements, you are strongly
9 encouraged to add tests in this directory to cover what you are
10 trying to fix or enhance. The later part of this short document
11 describes how your test scripts should be organized.
12
13
14 Running Tests
15 -------------
16
17 The easiest way to run tests is to say "make". This runs all
18 the 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
35 Since the tests all output TAP (see http://testanything.org) they can
36 be run with any TAP harness. Here's an example of parallel testing
37 powered 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
47 prove 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
53 You can give DEFAULT_TEST_TARGET=prove on the make command (or define it
54 in config.mak) to cause "make test" to run tests under prove.
55 GIT_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
59 You 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
70 You 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
72 appropriately 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`. Note that this can cause
88 failures in some tests which redirect and test the
89 output of shell functions. Use with caution.
90
91 -d::
92 --debug::
93 This may help the person who is developing a new test.
94 It causes the command defined with test_debug to run.
95 The "trash" directory (used to store all temporary data
96 during testing) is not deleted even if there are no
97 failed tests so that you can inspect its contents after
98 the test finished.
99
100 -i::
101 --immediate::
102 This causes the test to immediately exit upon the first
103 failed test. Cleanup commands requested with
104 test_when_finished are not executed if the test failed,
105 in order to keep the state for inspection by the tester
106 to diagnose the bug.
107
108 -l::
109 --long-tests::
110 This causes additional long-running tests to be run (where
111 available), for more exhaustive testing.
112
113 -r::
114 --run=<test-selector>::
115 Run only the subset of tests indicated by
116 <test-selector>. See section "Skipping Tests" below for
117 <test-selector> syntax.
118
119 --valgrind=<tool>::
120 Execute all Git binaries under valgrind tool <tool> and exit
121 with status 126 on errors (just like regular tests, this will
122 only stop the test script when running under -i).
123
124 Since it makes no sense to run the tests with --valgrind and
125 not see any output, this option implies --verbose. For
126 convenience, it also implies --tee.
127
128 <tool> defaults to 'memcheck', just like valgrind itself.
129 Other particularly useful choices include 'helgrind' and
130 'drd', but you may use any tool recognized by your valgrind
131 installation.
132
133 As a special case, <tool> can be 'memcheck-fast', which uses
134 memcheck but disables --track-origins. Use this if you are
135 running tests in bulk, to see if there are _any_ memory
136 issues.
137
138 Note that memcheck is run with the option --leak-check=no,
139 as the git process is short-lived and some errors are not
140 interesting. In order to run a single command under the same
141 conditions manually, you should set GIT_VALGRIND to point to
142 the 't/valgrind/' directory and use the commands under
143 't/valgrind/bin/'.
144
145 --valgrind-only=<pattern>::
146 Like --valgrind, but the effect is limited to tests with
147 numbers matching <pattern>. The number matched against is
148 simply the running count of the test within the file.
149
150 --tee::
151 In addition to printing the test output to the terminal,
152 write it to files named 't/test-results/$TEST_NAME.out'.
153 As the names depend on the tests' file names, it is safe to
154 run the tests with this option in parallel.
155
156 --with-dashes::
157 By default tests are run without dashed forms of
158 commands (like git-commit) in the PATH (it only uses
159 wrappers from ../bin-wrappers). Use this option to include
160 the build directory (..) in the PATH, which contains all
161 the dashed forms of commands. This option is currently
162 implied by other options like --valgrind and
163 GIT_TEST_INSTALLED.
164
165 --root=<directory>::
166 Create "trash" directories used to store all temporary data during
167 testing under <directory>, instead of the t/ directory.
168 Using this option with a RAM-based filesystem (such as tmpfs)
169 can massively speed up the test suite.
170
171 You can also set the GIT_TEST_INSTALLED environment variable to
172 the bindir of an existing git installation to test that installation.
173 You still need to have built this git sandbox, from which various
174 test-* support programs, templates, and perl libraries are used.
175 If your installed git is incomplete, it will silently test parts of
176 your built version instead.
177
178 When using GIT_TEST_INSTALLED, you can also set GIT_TEST_EXEC_PATH to
179 override the location of the dashed-form subcommands (what
180 GIT_EXEC_PATH would be used for during normal operation).
181 GIT_TEST_EXEC_PATH defaults to `$GIT_TEST_INSTALLED/git --exec-path`.
182
183
184 Skipping Tests
185 --------------
186
187 In some environments, certain tests have no way of succeeding
188 due to platform limitation, such as lack of 'unzip' program, or
189 filesystem that do not allow arbitrary sequence of non-NUL bytes
190 as pathnames.
191
192 You should be able to say something like
193
194 $ GIT_SKIP_TESTS=t9200.8 sh ./t9200-git-cvsexport-commit.sh
195
196 and even:
197
198 $ GIT_SKIP_TESTS='t[0-4]??? t91?? t9200.8' make
199
200 to omit such tests. The value of the environment variable is a
201 SP separated list of patterns that tells which tests to skip,
202 and either can match the "t[0-9]{4}" part to skip the whole
203 test, or t[0-9]{4} followed by ".$number" to say which
204 particular test to skip.
205
206 For an individual test suite --run could be used to specify that
207 only some tests should be run or that some tests should be
208 excluded from a run.
209
210 The argument for --run is a list of individual test numbers or
211 ranges with an optional negation prefix that define what tests in
212 a test suite to include in the run. A range is two numbers
213 separated with a dash and matches a range of tests with both ends
214 been included. You may omit the first or the second number to
215 mean "from the first test" or "up to the very last test"
216 respectively.
217
218 Optional prefix of '!' means that the test or a range of tests
219 should be excluded from the run.
220
221 If --run starts with an unprefixed number or range the initial
222 set of tests to run is empty. If the first item starts with '!'
223 all the tests are added to the initial set. After initial set is
224 determined every test number or range is added or excluded from
225 the set one by one, from left to right.
226
227 Individual numbers or ranges could be separated either by a space
228 or a comma.
229
230 For example, to run only tests up to a specific test (21), one
231 could do this:
232
233 $ sh ./t9200-git-cvsexport-commit.sh --run='1-21'
234
235 or this:
236
237 $ sh ./t9200-git-cvsexport-commit.sh --run='-21'
238
239 Common case is to run several setup tests (1, 2, 3) and then a
240 specific test (21) that relies on that setup:
241
242 $ sh ./t9200-git-cvsexport-commit.sh --run='1 2 3 21'
243
244 or:
245
246 $ sh ./t9200-git-cvsexport-commit.sh --run=1,2,3,21
247
248 or:
249
250 $ sh ./t9200-git-cvsexport-commit.sh --run='-3 21'
251
252 As noted above, the test set is built going though items left to
253 right, so this:
254
255 $ sh ./t9200-git-cvsexport-commit.sh --run='1-4 !3'
256
257 will run tests 1, 2, and 4. Items that comes later have higher
258 precendence. It means that this:
259
260 $ sh ./t9200-git-cvsexport-commit.sh --run='!3 1-4'
261
262 would just run tests from 1 to 4, including 3.
263
264 You may use negation with ranges. The following will run all
265 test in the test suite except from 7 up to 11:
266
267 $ sh ./t9200-git-cvsexport-commit.sh --run='!7-11'
268
269 Some tests in a test suite rely on the previous tests performing
270 certain actions, specifically some tests are designated as
271 "setup" test, so you cannot _arbitrarily_ disable one test and
272 expect the rest to function correctly.
273
274 --run is mostly useful when you want to focus on a specific test
275 and know what setup is needed for it. Or when you want to run
276 everything up to a certain test.
277
278
279 Naming Tests
280 ------------
281
282 The test files are named as:
283
284 tNNNN-commandname-details.sh
285
286 where N is a decimal digit.
287
288 First digit tells the family:
289
290 0 - the absolute basics and global stuff
291 1 - the basic commands concerning database
292 2 - the basic commands concerning the working tree
293 3 - the other basic commands (e.g. ls-files)
294 4 - the diff commands
295 5 - the pull and exporting commands
296 6 - the revision tree commands (even e.g. merge-base)
297 7 - the porcelainish commands concerning the working tree
298 8 - the porcelainish commands concerning forensics
299 9 - the git tools
300
301 Second digit tells the particular command we are testing.
302
303 Third digit (optionally) tells the particular switch or group of switches
304 we are testing.
305
306 If you create files under t/ directory (i.e. here) that is not
307 the top-level test script, never name the file to match the above
308 pattern. The Makefile here considers all such files as the
309 top-level test script and tries to run all of them. Care is
310 especially needed if you are creating a common test library
311 file, similar to test-lib.sh, because such a library file may
312 not be suitable for standalone execution.
313
314
315 Writing Tests
316 -------------
317
318 The test script is written as a shell script. It should start
319 with the standard "#!/bin/sh" with copyright notices, and an
320 assignment to variable 'test_description', like this:
321
322 #!/bin/sh
323 #
324 # Copyright (c) 2005 Junio C Hamano
325 #
326
327 test_description='xxx test (option --frotz)
328
329 This test registers the following structure in the cache
330 and tries to run git-ls-files with option --frotz.'
331
332
333 Source 'test-lib.sh'
334 --------------------
335
336 After assigning test_description, the test script should source
337 test-lib.sh like this:
338
339 . ./test-lib.sh
340
341 This test harness library does the following things:
342
343 - If the script is invoked with command line argument --help
344 (or -h), it shows the test_description and exits.
345
346 - Creates an empty test directory with an empty .git/objects database
347 and chdir(2) into it. This directory is 't/trash
348 directory.$test_name_without_dotsh', with t/ subject to change by
349 the --root option documented above.
350
351 - Defines standard test helper functions for your scripts to
352 use. These functions are designed to make all scripts behave
353 consistently when command line arguments --verbose (or -v),
354 --debug (or -d), and --immediate (or -i) is given.
355
356 Do's, don'ts & things to keep in mind
357 -------------------------------------
358
359 Here are a few examples of things you probably should and shouldn't do
360 when writing tests.
361
362 Do:
363
364 - Put all code inside test_expect_success and other assertions.
365
366 Even code that isn't a test per se, but merely some setup code
367 should be inside a test assertion.
368
369 - Chain your test assertions
370
371 Write test code like this:
372
373 git merge foo &&
374 git push bar &&
375 test ...
376
377 Instead of:
378
379 git merge hla
380 git push gh
381 test ...
382
383 That way all of the commands in your tests will succeed or fail. If
384 you must ignore the return value of something, consider using a
385 helper function (e.g. use sane_unset instead of unset, in order
386 to avoid unportable return value for unsetting a variable that was
387 already unset), or prepending the command with test_might_fail or
388 test_must_fail.
389
390 - Check the test coverage for your tests. See the "Test coverage"
391 below.
392
393 Don't blindly follow test coverage metrics; if a new function you added
394 doesn't have any coverage, then you're probably doing something wrong,
395 but having 100% coverage doesn't necessarily mean that you tested
396 everything.
397
398 Tests that are likely to smoke out future regressions are better
399 than tests that just inflate the coverage metrics.
400
401 - When a test checks for an absolute path that a git command generated,
402 construct the expected value using $(pwd) rather than $PWD,
403 $TEST_DIRECTORY, or $TRASH_DIRECTORY. It makes a difference on
404 Windows, where the shell (MSYS bash) mangles absolute path names.
405 For details, see the commit message of 4114156ae9.
406
407 Don't:
408
409 - exit() within a <script> part.
410
411 The harness will catch this as a programming error of the test.
412 Use test_done instead if you need to stop the tests early (see
413 "Skipping tests" below).
414
415 - use '! git cmd' when you want to make sure the git command exits
416 with failure in a controlled way by calling "die()". Instead,
417 use 'test_must_fail git cmd'. This will signal a failure if git
418 dies in an unexpected way (e.g. segfault).
419
420 On the other hand, don't use test_must_fail for running regular
421 platform commands; just use '! cmd'.
422
423 - use perl without spelling it as "$PERL_PATH". This is to help our
424 friends on Windows where the platform Perl often adds CR before
425 the end of line, and they bundle Git with a version of Perl that
426 does not do so, whose path is specified with $PERL_PATH. Note that we
427 provide a "perl" function which uses $PERL_PATH under the hood, so
428 you do not need to worry when simply running perl in the test scripts
429 (but you do, for example, on a shebang line or in a sub script
430 created via "write_script").
431
432 - use sh without spelling it as "$SHELL_PATH", when the script can
433 be misinterpreted by broken platform shell (e.g. Solaris).
434
435 - chdir around in tests. It is not sufficient to chdir to
436 somewhere and then chdir back to the original location later in
437 the test, as any intermediate step can fail and abort the test,
438 causing the next test to start in an unexpected directory. Do so
439 inside a subshell if necessary.
440
441 - Break the TAP output
442
443 The raw output from your test may be interpreted by a TAP harness. TAP
444 harnesses will ignore everything they don't know about, but don't step
445 on their toes in these areas:
446
447 - Don't print lines like "$x..$y" where $x and $y are integers.
448
449 - Don't print lines that begin with "ok" or "not ok".
450
451 TAP harnesses expect a line that begins with either "ok" and "not
452 ok" to signal a test passed or failed (and our harness already
453 produces such lines), so your script shouldn't emit such lines to
454 their output.
455
456 You can glean some further possible issues from the TAP grammar
457 (see http://search.cpan.org/perldoc?TAP::Parser::Grammar#TAP_Grammar)
458 but the best indication is to just run the tests with prove(1),
459 it'll complain if anything is amiss.
460
461 Keep in mind:
462
463 - Inside <script> part, the standard output and standard error
464 streams are discarded, and the test harness only reports "ok" or
465 "not ok" to the end user running the tests. Under --verbose, they
466 are shown to help debugging the tests.
467
468
469 Skipping tests
470 --------------
471
472 If you need to skip tests you should do so by using the three-arg form
473 of the test_* functions (see the "Test harness library" section
474 below), e.g.:
475
476 test_expect_success PERL 'I need Perl' '
477 perl -e "hlagh() if unf_unf()"
478 '
479
480 The advantage of skipping tests like this is that platforms that don't
481 have the PERL and other optional dependencies get an indication of how
482 many tests they're missing.
483
484 If the test code is too hairy for that (i.e. does a lot of setup work
485 outside test assertions) you can also skip all remaining tests by
486 setting skip_all and immediately call test_done:
487
488 if ! test_have_prereq PERL
489 then
490 skip_all='skipping perl interface tests, perl not available'
491 test_done
492 fi
493
494 The string you give to skip_all will be used as an explanation for why
495 the test was skipped.
496
497 End with test_done
498 ------------------
499
500 Your script will be a sequence of tests, using helper functions
501 from the test harness library. At the end of the script, call
502 'test_done'.
503
504
505 Test harness library
506 --------------------
507
508 There are a handful helper functions defined in the test harness
509 library for your script to use.
510
511 - test_expect_success [<prereq>] <message> <script>
512
513 Usually takes two strings as parameters, and evaluates the
514 <script>. If it yields success, test is considered
515 successful. <message> should state what it is testing.
516
517 Example:
518
519 test_expect_success \
520 'git-write-tree should be able to write an empty tree.' \
521 'tree=$(git-write-tree)'
522
523 If you supply three parameters the first will be taken to be a
524 prerequisite; see the test_set_prereq and test_have_prereq
525 documentation below:
526
527 test_expect_success TTY 'git --paginate rev-list uses a pager' \
528 ' ... '
529
530 You can also supply a comma-separated list of prerequisites, in the
531 rare case where your test depends on more than one:
532
533 test_expect_success PERL,PYTHON 'yo dawg' \
534 ' test $(perl -E 'print eval "1 +" . qx[python -c "print 2"]') == "4" '
535
536 - test_expect_failure [<prereq>] <message> <script>
537
538 This is NOT the opposite of test_expect_success, but is used
539 to mark a test that demonstrates a known breakage. Unlike
540 the usual test_expect_success tests, which say "ok" on
541 success and "FAIL" on failure, this will say "FIXED" on
542 success and "still broken" on failure. Failures from these
543 tests won't cause -i (immediate) to stop.
544
545 Like test_expect_success this function can optionally use a three
546 argument invocation with a prerequisite as the first argument.
547
548 - test_debug <script>
549
550 This takes a single argument, <script>, and evaluates it only
551 when the test script is started with --debug command line
552 argument. This is primarily meant for use during the
553 development of a new test script.
554
555 - test_done
556
557 Your test script must have test_done at the end. Its purpose
558 is to summarize successes and failures in the test script and
559 exit with an appropriate error code.
560
561 - test_tick
562
563 Make commit and tag names consistent by setting the author and
564 committer times to defined state. Subsequent calls will
565 advance the times by a fixed amount.
566
567 - test_commit <message> [<filename> [<contents>]]
568
569 Creates a commit with the given message, committing the given
570 file with the given contents (default for both is to reuse the
571 message string), and adds a tag (again reusing the message
572 string as name). Calls test_tick to make the SHA-1s
573 reproducible.
574
575 - test_merge <message> <commit-or-tag>
576
577 Merges the given rev using the given message. Like test_commit,
578 creates a tag and calls test_tick before committing.
579
580 - test_set_prereq <prereq>
581
582 Set a test prerequisite to be used later with test_have_prereq. The
583 test-lib will set some prerequisites for you, see the
584 "Prerequisites" section below for a full list of these.
585
586 Others you can set yourself and use later with either
587 test_have_prereq directly, or the three argument invocation of
588 test_expect_success and test_expect_failure.
589
590 - test_have_prereq <prereq>
591
592 Check if we have a prerequisite previously set with
593 test_set_prereq. The most common use of this directly is to skip
594 all the tests if we don't have some essential prerequisite:
595
596 if ! test_have_prereq PERL
597 then
598 skip_all='skipping perl interface tests, perl not available'
599 test_done
600 fi
601
602 - test_external [<prereq>] <message> <external> <script>
603
604 Execute a <script> with an <external> interpreter (like perl). This
605 was added for tests like t9700-perl-git.sh which do most of their
606 work in an external test script.
607
608 test_external \
609 'GitwebCache::*FileCache*' \
610 perl "$TEST_DIRECTORY"/t9503/test_cache_interface.pl
611
612 If the test is outputting its own TAP you should set the
613 test_external_has_tap variable somewhere before calling the first
614 test_external* function. See t9700-perl-git.sh for an example.
615
616 # The external test will outputs its own plan
617 test_external_has_tap=1
618
619 - test_external_without_stderr [<prereq>] <message> <external> <script>
620
621 Like test_external but fail if there's any output on stderr,
622 instead of checking the exit code.
623
624 test_external_without_stderr \
625 'Perl API' \
626 perl "$TEST_DIRECTORY"/t9700/test.pl
627
628 - test_expect_code <exit-code> <command>
629
630 Run a command and ensure that it exits with the given exit code.
631 For example:
632
633 test_expect_success 'Merge with d/f conflicts' '
634 test_expect_code 1 git merge "merge msg" B master
635 '
636
637 - test_must_fail <git-command>
638
639 Run a git command and ensure it fails in a controlled way. Use
640 this instead of "! <git-command>". When git-command dies due to a
641 segfault, test_must_fail diagnoses it as an error; "! <git-command>"
642 treats it as just another expected failure, which would let such a
643 bug go unnoticed.
644
645 - test_might_fail <git-command>
646
647 Similar to test_must_fail, but tolerate success, too. Use this
648 instead of "<git-command> || :" to catch failures due to segv.
649
650 - test_cmp <expected> <actual>
651
652 Check whether the content of the <actual> file matches the
653 <expected> file. This behaves like "cmp" but produces more
654 helpful output when the test is run with "-v" option.
655
656 - test_line_count (= | -lt | -ge | ...) <length> <file>
657
658 Check whether a file has the length it is expected to.
659
660 - test_path_is_file <path> [<diagnosis>]
661 test_path_is_dir <path> [<diagnosis>]
662 test_path_is_missing <path> [<diagnosis>]
663
664 Check if the named path is a file, if the named path is a
665 directory, or if the named path does not exist, respectively,
666 and fail otherwise, showing the <diagnosis> text.
667
668 - test_when_finished <script>
669
670 Prepend <script> to a list of commands to run to clean up
671 at the end of the current test. If some clean-up command
672 fails, the test will not pass.
673
674 Example:
675
676 test_expect_success 'branch pointing to non-commit' '
677 git rev-parse HEAD^{tree} >.git/refs/heads/invalid &&
678 test_when_finished "git update-ref -d refs/heads/invalid" &&
679 ...
680 '
681
682 - test_write_lines <lines>
683
684 Write <lines> on standard output, one line per argument.
685 Useful to prepare multi-line files in a compact form.
686
687 Example:
688
689 test_write_lines a b c d e f g >foo
690
691 Is a more compact equivalent of:
692 cat >foo <<-EOF
693 a
694 b
695 c
696 d
697 e
698 f
699 g
700 EOF
701
702
703 - test_pause
704
705 This command is useful for writing and debugging tests and must be
706 removed before submitting. It halts the execution of the test and
707 spawns a shell in the trash directory. Exit the shell to continue
708 the test. Example:
709
710 test_expect_success 'test' '
711 git do-something >actual &&
712 test_pause &&
713 test_cmp expected actual
714 '
715
716 - test_ln_s_add <path1> <path2>
717
718 This function helps systems whose filesystem does not support symbolic
719 links. Use it to add a symbolic link entry to the index when it is not
720 important that the file system entry is a symbolic link, i.e., instead
721 of the sequence
722
723 ln -s foo bar &&
724 git add bar
725
726 Sometimes it is possible to split a test in a part that does not need
727 the symbolic link in the file system and a part that does; then only
728 the latter part need be protected by a SYMLINKS prerequisite (see below).
729
730 Prerequisites
731 -------------
732
733 These are the prerequisites that the test library predefines with
734 test_have_prereq.
735
736 See the prereq argument to the test_* functions in the "Test harness
737 library" section above and the "test_have_prereq" function for how to
738 use these, and "test_set_prereq" for how to define your own.
739
740 - PYTHON
741
742 Git wasn't compiled with NO_PYTHON=YesPlease. Wrap any tests that
743 need Python with this.
744
745 - PERL
746
747 Git wasn't compiled with NO_PERL=YesPlease.
748
749 Even without the PERL prerequisite, tests can assume there is a
750 usable perl interpreter at $PERL_PATH, though it need not be
751 particularly modern.
752
753 - POSIXPERM
754
755 The filesystem supports POSIX style permission bits.
756
757 - BSLASHPSPEC
758
759 Backslashes in pathspec are not directory separators. This is not
760 set on Windows. See 6fd1106a for details.
761
762 - EXECKEEPSPID
763
764 The process retains the same pid across exec(2). See fb9a2bea for
765 details.
766
767 - PIPE
768
769 The filesystem we're on supports creation of FIFOs (named pipes)
770 via mkfifo(1).
771
772 - SYMLINKS
773
774 The filesystem we're on supports symbolic links. E.g. a FAT
775 filesystem doesn't support these. See 704a3143 for details.
776
777 - SANITY
778
779 Test is not run by root user, and an attempt to write to an
780 unwritable file is expected to fail correctly.
781
782 - LIBPCRE
783
784 Git was compiled with USE_LIBPCRE=YesPlease. Wrap any tests
785 that use git-grep --perl-regexp or git-grep -P in these.
786
787 - CASE_INSENSITIVE_FS
788
789 Test is run on a case insensitive file system.
790
791 - UTF8_NFD_TO_NFC
792
793 Test is run on a filesystem which converts decomposed utf-8 (nfd)
794 to precomposed utf-8 (nfc).
795
796 Tips for Writing Tests
797 ----------------------
798
799 As with any programming projects, existing programs are the best
800 source of the information. However, do _not_ emulate
801 t0000-basic.sh when writing your tests. The test is special in
802 that it tries to validate the very core of GIT. For example, it
803 knows that there will be 256 subdirectories under .git/objects/,
804 and it knows that the object ID of an empty tree is a certain
805 40-byte string. This is deliberately done so in t0000-basic.sh
806 because the things the very basic core test tries to achieve is
807 to serve as a basis for people who are changing the GIT internal
808 drastically. For these people, after making certain changes,
809 not seeing failures from the basic test _is_ a failure. And
810 such drastic changes to the core GIT that even changes these
811 otherwise supposedly stable object IDs should be accompanied by
812 an update to t0000-basic.sh.
813
814 However, other tests that simply rely on basic parts of the core
815 GIT working properly should not have that level of intimate
816 knowledge of the core GIT internals. If all the test scripts
817 hardcoded the object IDs like t0000-basic.sh does, that defeats
818 the purpose of t0000-basic.sh, which is to isolate that level of
819 validation in one place. Your test also ends up needing
820 updating when such a change to the internal happens, so do _not_
821 do it and leave the low level of validation to t0000-basic.sh.
822
823 Test coverage
824 -------------
825
826 You can use the coverage tests to find code paths that are not being
827 used or properly exercised yet.
828
829 To do that, run the coverage target at the top-level (not in the t/
830 directory):
831
832 make coverage
833
834 That'll compile Git with GCC's coverage arguments, and generate a test
835 report with gcov after the tests finish. Running the coverage tests
836 can take a while, since running the tests in parallel is incompatible
837 with GCC's coverage mode.
838
839 After the tests have run you can generate a list of untested
840 functions:
841
842 make coverage-untested-functions
843
844 You can also generate a detailed per-file HTML report using the
845 Devel::Cover module. To install it do:
846
847 # On Debian or Ubuntu:
848 sudo aptitude install libdevel-cover-perl
849
850 # From the CPAN with cpanminus
851 curl -L http://cpanmin.us | perl - --sudo --self-upgrade
852 cpanm --sudo Devel::Cover
853
854 Then, at the top-level:
855
856 make cover_db_html
857
858 That'll generate a detailed cover report in the "cover_db_html"
859 directory, which you can then copy to a webserver, or inspect locally
860 in a browser.