Remove obsolete note about native CPU byte format
[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 ***
21 * ok 1: .git/objects should be empty after git-init-db in an empty repo.
22 * ok 2: .git/objects should have 256 subdirectories.
23 * ok 3: git-update-cache without --add should fail adding.
24 ...
25 * ok 23: no diff after checkout and git-update-cache --refresh.
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
35 $ sh ./t0500-ls-files.sh
36 * ok 1: git-update-cache --add to add various paths.
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
57
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58Naming Tests
59------------
60
61The test files are named as:
62
63 tNNNN-commandname-details.sh
64
65where N is a decimal digit.
66
67First digit tells the family:
68
69 0 - the absolute basics and global stuff
70 1 - the basic commands concerning database
71 2 - the basic commands concerning the working tree
72 3 - the other basic commands (e.g. ls-files)
73 4 - the diff commands
74 5 - the pull and exporting commands
75 6 - the revision tree commands (even e.g. merge-base)
76
77Second digit tells the particular command we are testing.
78
79Third digit (optionally) tells the particular switch or group of switches
80we are testing.
81
82
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83Writing Tests
84-------------
85
86The test script is written as a shell script. It should start
87with the standard "#!/bin/sh" with copyright notices, and an
88assignment to variable 'test_description', like this:
89
90 #!/bin/sh
91 #
92 # Copyright (c) 2005 Junio C Hamano
93 #
94
95 test_description=xxx test (option --frotz)
96
97 This test registers the following structure in the cache
98 and tries to run git-ls-files with option --frotz.'
99
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101Source 'test-lib.sh'
102--------------------
103
104After assigning test_description, the test script should source
105test-lib.sh like this:
106
107 . ./test-lib.sh
108
109This test harness library does the following things:
110
111 - If the script is invoked with command line argument --help
112 (or -h), it shows the test_description and exits.
113
114 - Creates an empty test directory with an empty .git/objects
115 database and chdir(2) into it. This directory is 't/trash'
116 if you must know, but I do not think you care.
117
118 - Defines standard test helper functions for your scripts to
119 use. These functions are designed to make all scripts behave
120 consistently when command line arguments --verbose (or -v),
121 --debug (or -d), and --immediate (or -i) is given.
122
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123End with test_done
124------------------
125
126Your script will be a sequence of tests, using helper functions
127from the test harness library. At the end of the script, call
128'test_done'.
129
130
131Test harness library
132--------------------
133
134There are a handful helper functions defined in the test harness
135library for your script to use.
136
137 - test_expect_success <message> <script>
138
139 This takes two strings as parameter, and evaluates the
140 <script>. If it yields success, test is considered
141 successful. <message> should state what it is testing.
142
143 Example:
144
145 test_expect_success \
146 'git-write-tree should be able to write an empty tree.' \
147 'tree=$(git-write-tree)'
148
149 - test_expect_failure <message> <script>
150
151 This is the opposite of test_expect_success. If <script>
152 yields success, test is considered a failure.
153
154 Example:
155
156 test_expect_failure \
157 'git-update-cache without --add should fail adding.' \
158 'git-update-cache should-be-empty'
159
160 - test_debug <script>
161
162 This takes a single argument, <script>, and evaluates it only
163 when the test script is started with --debug command line
164 argument. This is primarily meant for use during the
165 development of a new test script.
166
167 - test_done
168
169 Your test script must have test_done at the end. Its purpose
170 is to summarize successes and failures in the test script and
171 exit with an appropriate error code.
172
173
174Tips for Writing Tests
175----------------------
176
177As with any programming projects, existing programs are the best
178source of the information. However, do _not_ emulate
179t0000-basic.sh when writing your tests. The test is special in
180that it tries to validate the very core of GIT. For example, it
181knows that there will be 256 subdirectories under .git/objects/,
182and it knows that the object ID of an empty tree is a certain
18340-byte string. This is deliberately done so in t0000-basic.sh
184because the things the very basic core test tries to achieve is
185to serve as a basis for people who are changing the GIT internal
186drastically. For these people, after making certain changes,
187not seeing failures from the basic test _is_ a failure. And
188such drastic changes to the core GIT that even changes these
189otherwise supposedly stable object IDs should be accompanied by
190an update to t0000-basic.sh.
191
192However, other tests that simply rely on basic parts of the core
193GIT working properly should not have that level of intimate
194knowledge of the core GIT internals. If all the test scripts
195hardcoded the object IDs like t0000-basic.sh does, that defeats
196the purpose of t0000-basic.sh, which is to isolate that level of
197validation in one place. Your test also ends up needing
198updating when such a change to the internal happens, so do _not_
199do it and leave the low level of validation to t0000-basic.sh.