t/README: Document the prereq functions, and 3-arg test_*
[git/git.git] / t / README
CommitLineData
986aa7f1
JH
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 ***
5099b99d
ÆAB
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
986aa7f1 24 ...
5099b99d
ÆAB
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
85b0b34e 36be run with any TAP harness. Here's an example of parallel testing
5099b99d
ÆAB
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
986aa7f1 52
5099b99d 53You can also run each test individually from command line, like this:
986aa7f1 54
5099b99d
ÆAB
55 $ sh ./t3010-ls-files-killed-modified.sh
56 ok 1 - git update-index --add to add various paths.
57 ok 2 - git ls-files -k to show killed files.
58 ok 3 - validate git ls-files -k output.
59 ok 4 - git ls-files -m to show modified files.
60 ok 5 - validate git ls-files -m output.
61 # passed all 5 test(s)
62 1..5
986aa7f1
JH
63
64You can pass --verbose (or -v), --debug (or -d), and --immediate
4e1be63c
JS
65(or -i) command line argument to the test, or by setting GIT_TEST_OPTS
66appropriately before running "make".
986aa7f1
JH
67
68--verbose::
69 This makes the test more verbose. Specifically, the
70 command being run and their output if any are also
71 output.
72
73--debug::
74 This may help the person who is developing a new test.
75 It causes the command defined with test_debug to run.
76
77--immediate::
78 This causes the test to immediately exit upon the first
79 failed test.
80
5e2c08c6
LW
81--long-tests::
82 This causes additional long-running tests to be run (where
83 available), for more exhaustive testing.
84
4e1be63c
JS
85--valgrind::
86 Execute all Git binaries with valgrind and exit with status
87 126 on errors (just like regular tests, this will only stop
88 the test script when running under -i). Valgrind errors
89 go to stderr, so you might want to pass the -v option, too.
986aa7f1 90
3da93652
JS
91 Since it makes no sense to run the tests with --valgrind and
92 not see any output, this option implies --verbose. For
93 convenience, it also implies --tee.
94
44138559
JS
95--tee::
96 In addition to printing the test output to the terminal,
97 write it to files named 't/test-results/$TEST_NAME.out'.
98 As the names depend on the tests' file names, it is safe to
99 run the tests with this option in parallel.
100
e4597aae
MO
101--with-dashes::
102 By default tests are run without dashed forms of
103 commands (like git-commit) in the PATH (it only uses
104 wrappers from ../bin-wrappers). Use this option to include
105 the build directory (..) in the PATH, which contains all
106 the dashed forms of commands. This option is currently
107 implied by other options like --valgrind and
108 GIT_TEST_INSTALLED.
109
0d4dbcd3
TR
110--root=<directory>::
111 Create "trash" directories used to store all temporary data during
112 testing under <directory>, instead of the t/ directory.
113 Using this option with a RAM-based filesystem (such as tmpfs)
114 can massively speed up the test suite.
115
e160da7f
MO
116You can also set the GIT_TEST_INSTALLED environment variable to
117the bindir of an existing git installation to test that installation.
118You still need to have built this git sandbox, from which various
119test-* support programs, templates, and perl libraries are used.
120If your installed git is incomplete, it will silently test parts of
121your built version instead.
122
123When using GIT_TEST_INSTALLED, you can also set GIT_TEST_EXEC_PATH to
124override the location of the dashed-form subcommands (what
125GIT_EXEC_PATH would be used for during normal operation).
126GIT_TEST_EXEC_PATH defaults to `$GIT_TEST_INSTALLED/git --exec-path`.
127
128
fbd458a3
JN
129Skipping Tests
130--------------
131
132In some environments, certain tests have no way of succeeding
133due to platform limitation, such as lack of 'unzip' program, or
134filesystem that do not allow arbitrary sequence of non-NUL bytes
135as pathnames.
136
137You should be able to say something like
138
139 $ GIT_SKIP_TESTS=t9200.8 sh ./t9200-git-cvsexport-commit.sh
140
141and even:
142
143 $ GIT_SKIP_TESTS='t[0-4]??? t91?? t9200.8' make
144
145to omit such tests. The value of the environment variable is a
146SP separated list of patterns that tells which tests to skip,
147and either can match the "t[0-9]{4}" part to skip the whole
148test, or t[0-9]{4} followed by ".$number" to say which
149particular test to skip.
150
151Note that some tests in the existing test suite rely on previous
152test item, so you cannot arbitrarily disable one and expect the
153remainder of test to check what the test originally was intended
154to check.
155
156
f50c9f76
PB
157Naming Tests
158------------
159
160The test files are named as:
161
162 tNNNN-commandname-details.sh
163
164where N is a decimal digit.
165
166First digit tells the family:
167
168 0 - the absolute basics and global stuff
169 1 - the basic commands concerning database
170 2 - the basic commands concerning the working tree
171 3 - the other basic commands (e.g. ls-files)
172 4 - the diff commands
173 5 - the pull and exporting commands
174 6 - the revision tree commands (even e.g. merge-base)
8f4a9b62 175 7 - the porcelainish commands concerning the working tree
8757749e
JN
176 8 - the porcelainish commands concerning forensics
177 9 - the git tools
f50c9f76
PB
178
179Second digit tells the particular command we are testing.
180
181Third digit (optionally) tells the particular switch or group of switches
182we are testing.
183
77656600
JH
184If you create files under t/ directory (i.e. here) that is not
185the top-level test script, never name the file to match the above
186pattern. The Makefile here considers all such files as the
187top-level test script and tries to run all of them. A care is
188especially needed if you are creating a common test library
189file, similar to test-lib.sh, because such a library file may
190not be suitable for standalone execution.
191
f50c9f76 192
986aa7f1
JH
193Writing Tests
194-------------
195
196The test script is written as a shell script. It should start
197with the standard "#!/bin/sh" with copyright notices, and an
198assignment to variable 'test_description', like this:
199
200 #!/bin/sh
201 #
202 # Copyright (c) 2005 Junio C Hamano
203 #
204
14cd1ff3 205 test_description='xxx test (option --frotz)
986aa7f1
JH
206
207 This test registers the following structure in the cache
208 and tries to run git-ls-files with option --frotz.'
209
f50c9f76 210
986aa7f1
JH
211Source 'test-lib.sh'
212--------------------
213
214After assigning test_description, the test script should source
215test-lib.sh like this:
216
217 . ./test-lib.sh
218
219This test harness library does the following things:
220
221 - If the script is invoked with command line argument --help
222 (or -h), it shows the test_description and exits.
223
e1ca1c9d
ÆAB
224 - Creates an empty test directory with an empty .git/objects database
225 and chdir(2) into it. This directory is 't/trash
226 directory.$test_name_without_dotsh', with t/ subject to change by
227 the --root option documented above.
986aa7f1
JH
228
229 - Defines standard test helper functions for your scripts to
230 use. These functions are designed to make all scripts behave
231 consistently when command line arguments --verbose (or -v),
232 --debug (or -d), and --immediate (or -i) is given.
233
14cd1ff3 234
986aa7f1
JH
235End with test_done
236------------------
237
238Your script will be a sequence of tests, using helper functions
239from the test harness library. At the end of the script, call
240'test_done'.
241
242
243Test harness library
244--------------------
245
246There are a handful helper functions defined in the test harness
247library for your script to use.
248
9a897893 249 - test_expect_success [<prereq>] <message> <script>
986aa7f1 250
9a897893 251 Usually takes two strings as parameter, and evaluates the
986aa7f1
JH
252 <script>. If it yields success, test is considered
253 successful. <message> should state what it is testing.
254
255 Example:
256
257 test_expect_success \
258 'git-write-tree should be able to write an empty tree.' \
259 'tree=$(git-write-tree)'
260
9a897893
ÆAB
261 If you supply three parameters the first will be taken to be a
262 prerequisite, see the test_set_prereq and test_have_prereq
263 documentation below:
264
265 test_expect_success TTY 'git --paginate rev-list uses a pager' \
266 ' ... '
267
268 - test_expect_failure [<prereq>] <message> <script>
986aa7f1 269
41ac414e
JH
270 This is NOT the opposite of test_expect_success, but is used
271 to mark a test that demonstrates a known breakage. Unlike
272 the usual test_expect_success tests, which say "ok" on
273 success and "FAIL" on failure, this will say "FIXED" on
274 success and "still broken" on failure. Failures from these
275 tests won't cause -i (immediate) to stop.
986aa7f1 276
9a897893
ÆAB
277 Like test_expect_success this function can optionally use a three
278 argument invocation with a prerequisite as the first argument.
279
986aa7f1
JH
280 - test_debug <script>
281
282 This takes a single argument, <script>, and evaluates it only
283 when the test script is started with --debug command line
284 argument. This is primarily meant for use during the
285 development of a new test script.
286
287 - test_done
288
289 Your test script must have test_done at the end. Its purpose
290 is to summarize successes and failures in the test script and
291 exit with an appropriate error code.
292
00884968
JS
293 - test_tick
294
295 Make commit and tag names consistent by setting the author and
296 committer times to defined stated. Subsequent calls will
297 advance the times by a fixed amount.
298
299 - test_commit <message> [<filename> [<contents>]]
300
301 Creates a commit with the given message, committing the given
302 file with the given contents (default for both is to reuse the
303 message string), and adds a tag (again reusing the message
304 string as name). Calls test_tick to make the SHA-1s
305 reproducible.
306
307 - test_merge <message> <commit-or-tag>
308
309 Merges the given rev using the given message. Like test_commit,
310 creates a tag and calls test_tick before committing.
986aa7f1 311
9a897893
ÆAB
312 - test_set_prereq SOME_PREREQ
313
314 Set a test prerequisite to be used later with test_have_prereq. The
315 test-lib will set some prerequisites for you, e.g. PERL and PYTHON
316 which are derived from ./GIT-BUILD-OPTIONS (grep test_set_prereq
317 test-lib.sh for more). Others you can set yourself and use later
318 with either test_have_prereq directly, or the three argument
319 invocation of test_expect_success and test_expect_failure.
320
321 - test_have_prereq SOME PREREQ
322
323 Check if we have a prerequisite previously set with
324 test_set_prereq. The most common use of this directly is to skip
325 all the tests if we don't have some essential prerequisite:
326
327 if ! test_have_prereq PERL
328 then
329 skip_all='skipping perl interface tests, perl not available'
330 test_done
331 fi
332
986aa7f1
JH
333Tips for Writing Tests
334----------------------
335
336As with any programming projects, existing programs are the best
337source of the information. However, do _not_ emulate
338t0000-basic.sh when writing your tests. The test is special in
339that it tries to validate the very core of GIT. For example, it
340knows that there will be 256 subdirectories under .git/objects/,
341and it knows that the object ID of an empty tree is a certain
34240-byte string. This is deliberately done so in t0000-basic.sh
343because the things the very basic core test tries to achieve is
344to serve as a basis for people who are changing the GIT internal
345drastically. For these people, after making certain changes,
346not seeing failures from the basic test _is_ a failure. And
347such drastic changes to the core GIT that even changes these
348otherwise supposedly stable object IDs should be accompanied by
349an update to t0000-basic.sh.
350
351However, other tests that simply rely on basic parts of the core
352GIT working properly should not have that level of intimate
353knowledge of the core GIT internals. If all the test scripts
354hardcoded the object IDs like t0000-basic.sh does, that defeats
355the purpose of t0000-basic.sh, which is to isolate that level of
356validation in one place. Your test also ends up needing
357updating when such a change to the internal happens, so do _not_
358do it and leave the low level of validation to t0000-basic.sh.