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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 --verbose::
75 This makes the test more verbose. Specifically, the
76 command being run and their output if any are also
77 output.
78
79 --debug::
80 This may help the person who is developing a new test.
81 It causes the command defined with test_debug to run.
82 The "trash" directory (used to store all temporary data
83 during testing) is not deleted even if there are no
84 failed tests so that you can inspect its contents after
85 the test finished.
86
87 --immediate::
88 This causes the test to immediately exit upon the first
89 failed test.
90
91 --long-tests::
92 This causes additional long-running tests to be run (where
93 available), for more exhaustive testing.
94
95 --valgrind::
96 Execute all Git binaries with valgrind and exit with status
97 126 on errors (just like regular tests, this will only stop
98 the test script when running under -i). Valgrind errors
99 go to stderr, so you might want to pass the -v option, too.
100
101 Since it makes no sense to run the tests with --valgrind and
102 not see any output, this option implies --verbose. For
103 convenience, it also implies --tee.
104
105 Note that valgrind is run with the option --leak-check=no,
106 as the git process is short-lived and some errors are not
107 interesting. In order to run a single command under the same
108 conditions manually, you should set GIT_VALGRIND to point to
109 the 't/valgrind/' directory and use the commands under
110 't/valgrind/bin/'.
111
112 --tee::
113 In addition to printing the test output to the terminal,
114 write it to files named 't/test-results/$TEST_NAME.out'.
115 As the names depend on the tests' file names, it is safe to
116 run the tests with this option in parallel.
117
118 --with-dashes::
119 By default tests are run without dashed forms of
120 commands (like git-commit) in the PATH (it only uses
121 wrappers from ../bin-wrappers). Use this option to include
122 the build directory (..) in the PATH, which contains all
123 the dashed forms of commands. This option is currently
124 implied by other options like --valgrind and
125 GIT_TEST_INSTALLED.
126
127 --root=<directory>::
128 Create "trash" directories used to store all temporary data during
129 testing under <directory>, instead of the t/ directory.
130 Using this option with a RAM-based filesystem (such as tmpfs)
131 can massively speed up the test suite.
132
133 You can also set the GIT_TEST_INSTALLED environment variable to
134 the bindir of an existing git installation to test that installation.
135 You still need to have built this git sandbox, from which various
136 test-* support programs, templates, and perl libraries are used.
137 If your installed git is incomplete, it will silently test parts of
138 your built version instead.
139
140 When using GIT_TEST_INSTALLED, you can also set GIT_TEST_EXEC_PATH to
141 override the location of the dashed-form subcommands (what
142 GIT_EXEC_PATH would be used for during normal operation).
143 GIT_TEST_EXEC_PATH defaults to `$GIT_TEST_INSTALLED/git --exec-path`.
144
145
146 Skipping Tests
147 --------------
148
149 In some environments, certain tests have no way of succeeding
150 due to platform limitation, such as lack of 'unzip' program, or
151 filesystem that do not allow arbitrary sequence of non-NUL bytes
152 as pathnames.
153
154 You should be able to say something like
155
156 $ GIT_SKIP_TESTS=t9200.8 sh ./t9200-git-cvsexport-commit.sh
157
158 and even:
159
160 $ GIT_SKIP_TESTS='t[0-4]??? t91?? t9200.8' make
161
162 to omit such tests. The value of the environment variable is a
163 SP separated list of patterns that tells which tests to skip,
164 and either can match the "t[0-9]{4}" part to skip the whole
165 test, or t[0-9]{4} followed by ".$number" to say which
166 particular test to skip.
167
168 Note that some tests in the existing test suite rely on previous
169 test item, so you cannot arbitrarily disable one and expect the
170 remainder of test to check what the test originally was intended
171 to check.
172
173
174 Naming Tests
175 ------------
176
177 The test files are named as:
178
179 tNNNN-commandname-details.sh
180
181 where N is a decimal digit.
182
183 First digit tells the family:
184
185 0 - the absolute basics and global stuff
186 1 - the basic commands concerning database
187 2 - the basic commands concerning the working tree
188 3 - the other basic commands (e.g. ls-files)
189 4 - the diff commands
190 5 - the pull and exporting commands
191 6 - the revision tree commands (even e.g. merge-base)
192 7 - the porcelainish commands concerning the working tree
193 8 - the porcelainish commands concerning forensics
194 9 - the git tools
195
196 Second digit tells the particular command we are testing.
197
198 Third digit (optionally) tells the particular switch or group of switches
199 we are testing.
200
201 If you create files under t/ directory (i.e. here) that is not
202 the top-level test script, never name the file to match the above
203 pattern. The Makefile here considers all such files as the
204 top-level test script and tries to run all of them. Care is
205 especially needed if you are creating a common test library
206 file, similar to test-lib.sh, because such a library file may
207 not be suitable for standalone execution.
208
209
210 Writing Tests
211 -------------
212
213 The test script is written as a shell script. It should start
214 with the standard "#!/bin/sh" with copyright notices, and an
215 assignment to variable 'test_description', like this:
216
217 #!/bin/sh
218 #
219 # Copyright (c) 2005 Junio C Hamano
220 #
221
222 test_description='xxx test (option --frotz)
223
224 This test registers the following structure in the cache
225 and tries to run git-ls-files with option --frotz.'
226
227
228 Source 'test-lib.sh'
229 --------------------
230
231 After assigning test_description, the test script should source
232 test-lib.sh like this:
233
234 . ./test-lib.sh
235
236 This test harness library does the following things:
237
238 - If the script is invoked with command line argument --help
239 (or -h), it shows the test_description and exits.
240
241 - Creates an empty test directory with an empty .git/objects database
242 and chdir(2) into it. This directory is 't/trash
243 directory.$test_name_without_dotsh', with t/ subject to change by
244 the --root option documented above.
245
246 - Defines standard test helper functions for your scripts to
247 use. These functions are designed to make all scripts behave
248 consistently when command line arguments --verbose (or -v),
249 --debug (or -d), and --immediate (or -i) is given.
250
251 Do's, don'ts & things to keep in mind
252 -------------------------------------
253
254 Here are a few examples of things you probably should and shouldn't do
255 when writing tests.
256
257 Do:
258
259 - Put all code inside test_expect_success and other assertions.
260
261 Even code that isn't a test per se, but merely some setup code
262 should be inside a test assertion.
263
264 - Chain your test assertions
265
266 Write test code like this:
267
268 git merge foo &&
269 git push bar &&
270 test ...
271
272 Instead of:
273
274 git merge hla
275 git push gh
276 test ...
277
278 That way all of the commands in your tests will succeed or fail. If
279 you must ignore the return value of something, consider using a
280 helper function (e.g. use sane_unset instead of unset, in order
281 to avoid unportable return value for unsetting a variable that was
282 already unset), or prepending the command with test_might_fail or
283 test_must_fail.
284
285 - Check the test coverage for your tests. See the "Test coverage"
286 below.
287
288 Don't blindly follow test coverage metrics; if a new function you added
289 doesn't have any coverage, then you're probably doing something wrong,
290 but having 100% coverage doesn't necessarily mean that you tested
291 everything.
292
293 Tests that are likely to smoke out future regressions are better
294 than tests that just inflate the coverage metrics.
295
296 - When a test checks for an absolute path that a git command generated,
297 construct the expected value using $(pwd) rather than $PWD,
298 $TEST_DIRECTORY, or $TRASH_DIRECTORY. It makes a difference on
299 Windows, where the shell (MSYS bash) mangles absolute path names.
300 For details, see the commit message of 4114156ae9.
301
302 Don't:
303
304 - exit() within a <script> part.
305
306 The harness will catch this as a programming error of the test.
307 Use test_done instead if you need to stop the tests early (see
308 "Skipping tests" below).
309
310 - Break the TAP output
311
312 The raw output from your test may be interpreted by a TAP harness. TAP
313 harnesses will ignore everything they don't know about, but don't step
314 on their toes in these areas:
315
316 - Don't print lines like "$x..$y" where $x and $y are integers.
317
318 - Don't print lines that begin with "ok" or "not ok".
319
320 TAP harnesses expect a line that begins with either "ok" and "not
321 ok" to signal a test passed or failed (and our harness already
322 produces such lines), so your script shouldn't emit such lines to
323 their output.
324
325 You can glean some further possible issues from the TAP grammar
326 (see http://search.cpan.org/perldoc?TAP::Parser::Grammar#TAP_Grammar)
327 but the best indication is to just run the tests with prove(1),
328 it'll complain if anything is amiss.
329
330 Keep in mind:
331
332 - Inside <script> part, the standard output and standard error
333 streams are discarded, and the test harness only reports "ok" or
334 "not ok" to the end user running the tests. Under --verbose, they
335 are shown to help debugging the tests.
336
337
338 Skipping tests
339 --------------
340
341 If you need to skip tests you should do so by using the three-arg form
342 of the test_* functions (see the "Test harness library" section
343 below), e.g.:
344
345 test_expect_success PERL 'I need Perl' "
346 '$PERL_PATH' -e 'hlagh() if unf_unf()'
347 "
348
349 The advantage of skipping tests like this is that platforms that don't
350 have the PERL and other optional dependencies get an indication of how
351 many tests they're missing.
352
353 If the test code is too hairy for that (i.e. does a lot of setup work
354 outside test assertions) you can also skip all remaining tests by
355 setting skip_all and immediately call test_done:
356
357 if ! test_have_prereq PERL
358 then
359 skip_all='skipping perl interface tests, perl not available'
360 test_done
361 fi
362
363 The string you give to skip_all will be used as an explanation for why
364 the test was skipped.
365
366 End with test_done
367 ------------------
368
369 Your script will be a sequence of tests, using helper functions
370 from the test harness library. At the end of the script, call
371 'test_done'.
372
373
374 Test harness library
375 --------------------
376
377 There are a handful helper functions defined in the test harness
378 library for your script to use.
379
380 - test_expect_success [<prereq>] <message> <script>
381
382 Usually takes two strings as parameters, and evaluates the
383 <script>. If it yields success, test is considered
384 successful. <message> should state what it is testing.
385
386 Example:
387
388 test_expect_success \
389 'git-write-tree should be able to write an empty tree.' \
390 'tree=$(git-write-tree)'
391
392 If you supply three parameters the first will be taken to be a
393 prerequisite; see the test_set_prereq and test_have_prereq
394 documentation below:
395
396 test_expect_success TTY 'git --paginate rev-list uses a pager' \
397 ' ... '
398
399 You can also supply a comma-separated list of prerequisites, in the
400 rare case where your test depends on more than one:
401
402 test_expect_success PERL,PYTHON 'yo dawg' \
403 ' test $(perl -E 'print eval "1 +" . qx[python -c "print 2"]') == "4" '
404
405 - test_expect_failure [<prereq>] <message> <script>
406
407 This is NOT the opposite of test_expect_success, but is used
408 to mark a test that demonstrates a known breakage. Unlike
409 the usual test_expect_success tests, which say "ok" on
410 success and "FAIL" on failure, this will say "FIXED" on
411 success and "still broken" on failure. Failures from these
412 tests won't cause -i (immediate) to stop.
413
414 Like test_expect_success this function can optionally use a three
415 argument invocation with a prerequisite as the first argument.
416
417 - test_debug <script>
418
419 This takes a single argument, <script>, and evaluates it only
420 when the test script is started with --debug command line
421 argument. This is primarily meant for use during the
422 development of a new test script.
423
424 - test_done
425
426 Your test script must have test_done at the end. Its purpose
427 is to summarize successes and failures in the test script and
428 exit with an appropriate error code.
429
430 - test_tick
431
432 Make commit and tag names consistent by setting the author and
433 committer times to defined state. Subsequent calls will
434 advance the times by a fixed amount.
435
436 - test_commit <message> [<filename> [<contents>]]
437
438 Creates a commit with the given message, committing the given
439 file with the given contents (default for both is to reuse the
440 message string), and adds a tag (again reusing the message
441 string as name). Calls test_tick to make the SHA-1s
442 reproducible.
443
444 - test_merge <message> <commit-or-tag>
445
446 Merges the given rev using the given message. Like test_commit,
447 creates a tag and calls test_tick before committing.
448
449 - test_set_prereq <prereq>
450
451 Set a test prerequisite to be used later with test_have_prereq. The
452 test-lib will set some prerequisites for you, see the
453 "Prerequisites" section below for a full list of these.
454
455 Others you can set yourself and use later with either
456 test_have_prereq directly, or the three argument invocation of
457 test_expect_success and test_expect_failure.
458
459 - test_have_prereq <prereq>
460
461 Check if we have a prerequisite previously set with
462 test_set_prereq. The most common use of this directly is to skip
463 all the tests if we don't have some essential prerequisite:
464
465 if ! test_have_prereq PERL
466 then
467 skip_all='skipping perl interface tests, perl not available'
468 test_done
469 fi
470
471 - test_external [<prereq>] <message> <external> <script>
472
473 Execute a <script> with an <external> interpreter (like perl). This
474 was added for tests like t9700-perl-git.sh which do most of their
475 work in an external test script.
476
477 test_external \
478 'GitwebCache::*FileCache*' \
479 "$PERL_PATH" "$TEST_DIRECTORY"/t9503/test_cache_interface.pl
480
481 If the test is outputting its own TAP you should set the
482 test_external_has_tap variable somewhere before calling the first
483 test_external* function. See t9700-perl-git.sh for an example.
484
485 # The external test will outputs its own plan
486 test_external_has_tap=1
487
488 - test_external_without_stderr [<prereq>] <message> <external> <script>
489
490 Like test_external but fail if there's any output on stderr,
491 instead of checking the exit code.
492
493 test_external_without_stderr \
494 'Perl API' \
495 "$PERL_PATH" "$TEST_DIRECTORY"/t9700/test.pl
496
497 - test_expect_code <exit-code> <command>
498
499 Run a command and ensure that it exits with the given exit code.
500 For example:
501
502 test_expect_success 'Merge with d/f conflicts' '
503 test_expect_code 1 git merge "merge msg" B master
504 '
505
506 - test_must_fail <git-command>
507
508 Run a git command and ensure it fails in a controlled way. Use
509 this instead of "! <git-command>". When git-command dies due to a
510 segfault, test_must_fail diagnoses it as an error; "! <git-command>"
511 treats it as just another expected failure, which would let such a
512 bug go unnoticed.
513
514 - test_might_fail <git-command>
515
516 Similar to test_must_fail, but tolerate success, too. Use this
517 instead of "<git-command> || :" to catch failures due to segv.
518
519 - test_cmp <expected> <actual>
520
521 Check whether the content of the <actual> file matches the
522 <expected> file. This behaves like "cmp" but produces more
523 helpful output when the test is run with "-v" option.
524
525 - test_line_count (= | -lt | -ge | ...) <length> <file>
526
527 Check whether a file has the length it is expected to.
528
529 - test_path_is_file <path> [<diagnosis>]
530 test_path_is_dir <path> [<diagnosis>]
531 test_path_is_missing <path> [<diagnosis>]
532
533 Check if the named path is a file, if the named path is a
534 directory, or if the named path does not exist, respectively,
535 and fail otherwise, showing the <diagnosis> text.
536
537 - test_when_finished <script>
538
539 Prepend <script> to a list of commands to run to clean up
540 at the end of the current test. If some clean-up command
541 fails, the test will not pass.
542
543 Example:
544
545 test_expect_success 'branch pointing to non-commit' '
546 git rev-parse HEAD^{tree} >.git/refs/heads/invalid &&
547 test_when_finished "git update-ref -d refs/heads/invalid" &&
548 ...
549 '
550
551 - test_pause
552
553 This command is useful for writing and debugging tests and must be
554 removed before submitting. It halts the execution of the test and
555 spawns a shell in the trash directory. Exit the shell to continue
556 the test. Example:
557
558 test_expect_success 'test' '
559 git do-something >actual &&
560 test_pause &&
561 test_cmp expected actual
562 '
563
564 Prerequisites
565 -------------
566
567 These are the prerequisites that the test library predefines with
568 test_have_prereq.
569
570 See the prereq argument to the test_* functions in the "Test harness
571 library" section above and the "test_have_prereq" function for how to
572 use these, and "test_set_prereq" for how to define your own.
573
574 - PERL & PYTHON
575
576 Git wasn't compiled with NO_PERL=YesPlease or
577 NO_PYTHON=YesPlease. Wrap any tests that need Perl or Python in
578 these.
579
580 - POSIXPERM
581
582 The filesystem supports POSIX style permission bits.
583
584 - BSLASHPSPEC
585
586 Backslashes in pathspec are not directory separators. This is not
587 set on Windows. See 6fd1106a for details.
588
589 - EXECKEEPSPID
590
591 The process retains the same pid across exec(2). See fb9a2bea for
592 details.
593
594 - SYMLINKS
595
596 The filesystem we're on supports symbolic links. E.g. a FAT
597 filesystem doesn't support these. See 704a3143 for details.
598
599 - SANITY
600
601 Test is not run by root user, and an attempt to write to an
602 unwritable file is expected to fail correctly.
603
604 - LIBPCRE
605
606 Git was compiled with USE_LIBPCRE=YesPlease. Wrap any tests
607 that use git-grep --perl-regexp or git-grep -P in these.
608
609 Tips for Writing Tests
610 ----------------------
611
612 As with any programming projects, existing programs are the best
613 source of the information. However, do _not_ emulate
614 t0000-basic.sh when writing your tests. The test is special in
615 that it tries to validate the very core of GIT. For example, it
616 knows that there will be 256 subdirectories under .git/objects/,
617 and it knows that the object ID of an empty tree is a certain
618 40-byte string. This is deliberately done so in t0000-basic.sh
619 because the things the very basic core test tries to achieve is
620 to serve as a basis for people who are changing the GIT internal
621 drastically. For these people, after making certain changes,
622 not seeing failures from the basic test _is_ a failure. And
623 such drastic changes to the core GIT that even changes these
624 otherwise supposedly stable object IDs should be accompanied by
625 an update to t0000-basic.sh.
626
627 However, other tests that simply rely on basic parts of the core
628 GIT working properly should not have that level of intimate
629 knowledge of the core GIT internals. If all the test scripts
630 hardcoded the object IDs like t0000-basic.sh does, that defeats
631 the purpose of t0000-basic.sh, which is to isolate that level of
632 validation in one place. Your test also ends up needing
633 updating when such a change to the internal happens, so do _not_
634 do it and leave the low level of validation to t0000-basic.sh.
635
636 Test coverage
637 -------------
638
639 You can use the coverage tests to find code paths that are not being
640 used or properly exercised yet.
641
642 To do that, run the coverage target at the top-level (not in the t/
643 directory):
644
645 make coverage
646
647 That'll compile Git with GCC's coverage arguments, and generate a test
648 report with gcov after the tests finish. Running the coverage tests
649 can take a while, since running the tests in parallel is incompatible
650 with GCC's coverage mode.
651
652 After the tests have run you can generate a list of untested
653 functions:
654
655 make coverage-untested-functions
656
657 You can also generate a detailed per-file HTML report using the
658 Devel::Cover module. To install it do:
659
660 # On Debian or Ubuntu:
661 sudo aptitude install libdevel-cover-perl
662
663 # From the CPAN with cpanminus
664 curl -L http://cpanmin.us | perl - --sudo --self-upgrade
665 cpanm --sudo Devel::Cover
666
667 Then, at the top-level:
668
669 make cover_db_html
670
671 That'll generate a detailed cover report in the "cover_db_html"
672 directory, which you can then copy to a webserver, or inspect locally
673 in a browser.