Print errno upon failure to open the COMMIT_EDITMSG file
[git/git.git] / t / README
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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 ***
5c94f87e 21 * ok 1: .git/objects should be empty after git-init in an empty repo.
986aa7f1 22 * ok 2: .git/objects should have 256 subdirectories.
215a7ad1 23 * ok 3: git-update-index without --add should fail adding.
986aa7f1 24 ...
215a7ad1 25 * ok 23: no diff after checkout and git-update-index --refresh.
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26 * passed all 23 test(s)
27 *** t0100-environment-names.sh ***
28 * ok 1: using old names should issue warnings.
29 * ok 2: using old names but having new names should not issue warnings.
30 ...
31
32Or you can run each test individually from command line, like
33this:
34
14cd1ff3 35 $ sh ./t3001-ls-files-killed.sh
215a7ad1 36 * ok 1: git-update-index --add to add various paths.
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37 * ok 2: git-ls-files -k to show killed files.
38 * ok 3: validate git-ls-files -k output.
39 * passed all 3 test(s)
40
41You can pass --verbose (or -v), --debug (or -d), and --immediate
42(or -i) command line argument to the test.
43
44--verbose::
45 This makes the test more verbose. Specifically, the
46 command being run and their output if any are also
47 output.
48
49--debug::
50 This may help the person who is developing a new test.
51 It causes the command defined with test_debug to run.
52
53--immediate::
54 This causes the test to immediately exit upon the first
55 failed test.
56
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57--long-tests::
58 This causes additional long-running tests to be run (where
59 available), for more exhaustive testing.
60
986aa7f1 61
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62Naming Tests
63------------
64
65The test files are named as:
66
67 tNNNN-commandname-details.sh
68
69where N is a decimal digit.
70
71First digit tells the family:
72
73 0 - the absolute basics and global stuff
74 1 - the basic commands concerning database
75 2 - the basic commands concerning the working tree
76 3 - the other basic commands (e.g. ls-files)
77 4 - the diff commands
78 5 - the pull and exporting commands
79 6 - the revision tree commands (even e.g. merge-base)
8f4a9b62 80 7 - the porcelainish commands concerning the working tree
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81 8 - the porcelainish commands concerning forensics
82 9 - the git tools
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83
84Second digit tells the particular command we are testing.
85
86Third digit (optionally) tells the particular switch or group of switches
87we are testing.
88
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89If you create files under t/ directory (i.e. here) that is not
90the top-level test script, never name the file to match the above
91pattern. The Makefile here considers all such files as the
92top-level test script and tries to run all of them. A care is
93especially needed if you are creating a common test library
94file, similar to test-lib.sh, because such a library file may
95not be suitable for standalone execution.
96
f50c9f76 97
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98Writing Tests
99-------------
100
101The test script is written as a shell script. It should start
102with the standard "#!/bin/sh" with copyright notices, and an
103assignment to variable 'test_description', like this:
104
105 #!/bin/sh
106 #
107 # Copyright (c) 2005 Junio C Hamano
108 #
109
14cd1ff3 110 test_description='xxx test (option --frotz)
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111
112 This test registers the following structure in the cache
113 and tries to run git-ls-files with option --frotz.'
114
f50c9f76 115
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116Source 'test-lib.sh'
117--------------------
118
119After assigning test_description, the test script should source
120test-lib.sh like this:
121
122 . ./test-lib.sh
123
124This test harness library does the following things:
125
126 - If the script is invoked with command line argument --help
127 (or -h), it shows the test_description and exits.
128
129 - Creates an empty test directory with an empty .git/objects
9231e3a9 130 database and chdir(2) into it. This directory is 't/trash directory'
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131 if you must know, but I do not think you care.
132
133 - Defines standard test helper functions for your scripts to
134 use. These functions are designed to make all scripts behave
135 consistently when command line arguments --verbose (or -v),
136 --debug (or -d), and --immediate (or -i) is given.
137
14cd1ff3 138
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139End with test_done
140------------------
141
142Your script will be a sequence of tests, using helper functions
143from the test harness library. At the end of the script, call
144'test_done'.
145
146
147Test harness library
148--------------------
149
150There are a handful helper functions defined in the test harness
151library for your script to use.
152
153 - test_expect_success <message> <script>
154
155 This takes two strings as parameter, and evaluates the
156 <script>. If it yields success, test is considered
157 successful. <message> should state what it is testing.
158
159 Example:
160
161 test_expect_success \
162 'git-write-tree should be able to write an empty tree.' \
163 'tree=$(git-write-tree)'
164
165 - test_expect_failure <message> <script>
166
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167 This is NOT the opposite of test_expect_success, but is used
168 to mark a test that demonstrates a known breakage. Unlike
169 the usual test_expect_success tests, which say "ok" on
170 success and "FAIL" on failure, this will say "FIXED" on
171 success and "still broken" on failure. Failures from these
172 tests won't cause -i (immediate) to stop.
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173
174 - test_debug <script>
175
176 This takes a single argument, <script>, and evaluates it only
177 when the test script is started with --debug command line
178 argument. This is primarily meant for use during the
179 development of a new test script.
180
181 - test_done
182
183 Your test script must have test_done at the end. Its purpose
184 is to summarize successes and failures in the test script and
185 exit with an appropriate error code.
186
187
188Tips for Writing Tests
189----------------------
190
191As with any programming projects, existing programs are the best
192source of the information. However, do _not_ emulate
193t0000-basic.sh when writing your tests. The test is special in
194that it tries to validate the very core of GIT. For example, it
195knows that there will be 256 subdirectories under .git/objects/,
196and it knows that the object ID of an empty tree is a certain
19740-byte string. This is deliberately done so in t0000-basic.sh
198because the things the very basic core test tries to achieve is
199to serve as a basis for people who are changing the GIT internal
200drastically. For these people, after making certain changes,
201not seeing failures from the basic test _is_ a failure. And
202such drastic changes to the core GIT that even changes these
203otherwise supposedly stable object IDs should be accompanied by
204an update to t0000-basic.sh.
205
206However, other tests that simply rely on basic parts of the core
207GIT working properly should not have that level of intimate
208knowledge of the core GIT internals. If all the test scripts
209hardcoded the object IDs like t0000-basic.sh does, that defeats
210the purpose of t0000-basic.sh, which is to isolate that level of
211validation in one place. Your test also ends up needing
212updating when such a change to the internal happens, so do _not_
213do it and leave the low level of validation to t0000-basic.sh.