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-db in an empty repo.
  22     *   ok 2: .git/objects should have 256 subdirectories.
  23     *   ok 3: git-update-index without --add should fail adding.
  24     ...
  25     *   ok 23: no diff after checkout and git-update-index --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
  32 Or you can run each test individually from command line, like
  33 this:
  34
  35     $ sh ./t3001-ls-files-killed.sh
  36     *   ok 1: git-update-index --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
  41 You 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
  58 Naming Tests
  59 ------------
  60
  61 The test files are named as:
  62
  63         tNNNN-commandname-details.sh
  64
  65 where N is a decimal digit.
  66
  67 First 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
  77 Second digit tells the particular command we are testing.
  78
  79 Third digit (optionally) tells the particular switch or group of switches
  80 we are testing.
  81
  82 If you create files under t/ directory (i.e. here) that is not
  83 the top-level test script, never name the file to match the above
  84 pattern.  The Makefile here considers all such files as the
  85 top-level test script and tries to run all of them.  A care is
  86 especially needed if you are creating a common test library
  87 file, similar to test-lib.sh, because such a library file may
  88 not be suitable for standalone execution.
  89
  90
  91 Writing Tests
  92 -------------
  93
  94 The test script is written as a shell script.  It should start
  95 with the standard "#!/bin/sh" with copyright notices, and an
  96 assignment to variable 'test_description', like this:
  97
  98         #!/bin/sh
  99         #
 100         # Copyright (c) 2005 Junio C Hamano
 101         #
 102
 103         test_description='xxx test (option --frotz)
 104
 105         This test registers the following structure in the cache
 106         and tries to run git-ls-files with option --frotz.'
 107
 108
 109 Source 'test-lib.sh'
 110 --------------------
 111
 112 After assigning test_description, the test script should source
 113 test-lib.sh like this:
 114
 115         . ./test-lib.sh
 116
 117 This test harness library does the following things:
 118
 119  - If the script is invoked with command line argument --help
 120    (or -h), it shows the test_description and exits.
 121
 122  - Creates an empty test directory with an empty .git/objects
 123    database and chdir(2) into it.  This directory is 't/trash'
 124    if you must know, but I do not think you care.
 125
 126  - Defines standard test helper functions for your scripts to
 127    use.  These functions are designed to make all scripts behave
 128    consistently when command line arguments --verbose (or -v),
 129    --debug (or -d), and --immediate (or -i) is given.
 130
 131
 132 End with test_done
 133 ------------------
 134
 135 Your script will be a sequence of tests, using helper functions
 136 from the test harness library.  At the end of the script, call
 137 'test_done'.
 138
 139
 140 Test harness library
 141 --------------------
 142
 143 There are a handful helper functions defined in the test harness
 144 library for your script to use.
 145
 146  - test_expect_success <message> <script>
 147
 148    This takes two strings as parameter, and evaluates the
 149    <script>.  If it yields success, test is considered
 150    successful.  <message> should state what it is testing.
 151
 152    Example:
 153
 154         test_expect_success \
 155             'git-write-tree should be able to write an empty tree.' \
 156             'tree=$(git-write-tree)'
 157
 158  - test_expect_failure <message> <script>
 159
 160    This is the opposite of test_expect_success.  If <script>
 161    yields success, test is considered a failure.
 162
 163    Example:
 164
 165         test_expect_failure \
 166             'git-update-index without --add should fail adding.' \
 167             'git-update-index should-be-empty'
 168
 169  - test_debug <script>
 170
 171    This takes a single argument, <script>, and evaluates it only
 172    when the test script is started with --debug command line
 173    argument.  This is primarily meant for use during the
 174    development of a new test script.
 175
 176  - test_done
 177
 178    Your test script must have test_done at the end.  Its purpose
 179    is to summarize successes and failures in the test script and
 180    exit with an appropriate error code.
 181
 182
 183 Tips for Writing Tests
 184 ----------------------
 185
 186 As with any programming projects, existing programs are the best
 187 source of the information.  However, do _not_ emulate
 188 t0000-basic.sh when writing your tests.  The test is special in
 189 that it tries to validate the very core of GIT.  For example, it
 190 knows that there will be 256 subdirectories under .git/objects/,
 191 and it knows that the object ID of an empty tree is a certain
 192 40-byte string.  This is deliberately done so in t0000-basic.sh
 193 because the things the very basic core test tries to achieve is
 194 to serve as a basis for people who are changing the GIT internal
 195 drastically.  For these people, after making certain changes,
 196 not seeing failures from the basic test _is_ a failure.  And
 197 such drastic changes to the core GIT that even changes these
 198 otherwise supposedly stable object IDs should be accompanied by
 199 an update to t0000-basic.sh.
 200
 201 However, other tests that simply rely on basic parts of the core
 202 GIT working properly should not have that level of intimate
 203 knowledge of the core GIT internals.  If all the test scripts
 204 hardcoded the object IDs like t0000-basic.sh does, that defeats
 205 the purpose of t0000-basic.sh, which is to isolate that level of
 206 validation in one place.  Your test also ends up needing
 207 updating when such a change to the internal happens, so do _not_
 208 do it and leave the low level of validation to t0000-basic.sh.