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         7 - the porcelainish commands concerning the working tree
  77
  78 Second digit tells the particular command we are testing.
  79
  80 Third digit (optionally) tells the particular switch or group of switches
  81 we are testing.
  82
  83 If you create files under t/ directory (i.e. here) that is not
  84 the top-level test script, never name the file to match the above
  85 pattern.  The Makefile here considers all such files as the
  86 top-level test script and tries to run all of them.  A care is
  87 especially needed if you are creating a common test library
  88 file, similar to test-lib.sh, because such a library file may
  89 not be suitable for standalone execution.
  90
  91
  92 Writing Tests
  93 -------------
  94
  95 The test script is written as a shell script.  It should start
  96 with the standard "#!/bin/sh" with copyright notices, and an
  97 assignment to variable 'test_description', like this:
  98
  99         #!/bin/sh
 100         #
 101         # Copyright (c) 2005 Junio C Hamano
 102         #
 103
 104         test_description='xxx test (option --frotz)
 105
 106         This test registers the following structure in the cache
 107         and tries to run git-ls-files with option --frotz.'
 108
 109
 110 Source 'test-lib.sh'
 111 --------------------
 112
 113 After assigning test_description, the test script should source
 114 test-lib.sh like this:
 115
 116         . ./test-lib.sh
 117
 118 This test harness library does the following things:
 119
 120  - If the script is invoked with command line argument --help
 121    (or -h), it shows the test_description and exits.
 122
 123  - Creates an empty test directory with an empty .git/objects
 124    database and chdir(2) into it.  This directory is 't/trash'
 125    if you must know, but I do not think you care.
 126
 127  - Defines standard test helper functions for your scripts to
 128    use.  These functions are designed to make all scripts behave
 129    consistently when command line arguments --verbose (or -v),
 130    --debug (or -d), and --immediate (or -i) is given.
 131
 132
 133 End with test_done
 134 ------------------
 135
 136 Your script will be a sequence of tests, using helper functions
 137 from the test harness library.  At the end of the script, call
 138 'test_done'.
 139
 140
 141 Test harness library
 142 --------------------
 143
 144 There are a handful helper functions defined in the test harness
 145 library for your script to use.
 146
 147  - test_expect_success <message> <script>
 148
 149    This takes two strings as parameter, and evaluates the
 150    <script>.  If it yields success, test is considered
 151    successful.  <message> should state what it is testing.
 152
 153    Example:
 154
 155         test_expect_success \
 156             'git-write-tree should be able to write an empty tree.' \
 157             'tree=$(git-write-tree)'
 158
 159  - test_expect_failure <message> <script>
 160
 161    This is the opposite of test_expect_success.  If <script>
 162    yields success, test is considered a failure.
 163
 164    Example:
 165
 166         test_expect_failure \
 167             'git-update-index without --add should fail adding.' \
 168             'git-update-index should-be-empty'
 169
 170  - test_debug <script>
 171
 172    This takes a single argument, <script>, and evaluates it only
 173    when the test script is started with --debug command line
 174    argument.  This is primarily meant for use during the
 175    development of a new test script.
 176
 177  - test_done
 178
 179    Your test script must have test_done at the end.  Its purpose
 180    is to summarize successes and failures in the test script and
 181    exit with an appropriate error code.
 182
 183
 184 Tips for Writing Tests
 185 ----------------------
 186
 187 As with any programming projects, existing programs are the best
 188 source of the information.  However, do _not_ emulate
 189 t0000-basic.sh when writing your tests.  The test is special in
 190 that it tries to validate the very core of GIT.  For example, it
 191 knows that there will be 256 subdirectories under .git/objects/,
 192 and it knows that the object ID of an empty tree is a certain
 193 40-byte string.  This is deliberately done so in t0000-basic.sh
 194 because the things the very basic core test tries to achieve is
 195 to serve as a basis for people who are changing the GIT internal
 196 drastically.  For these people, after making certain changes,
 197 not seeing failures from the basic test _is_ a failure.  And
 198 such drastic changes to the core GIT that even changes these
 199 otherwise supposedly stable object IDs should be accompanied by
 200 an update to t0000-basic.sh.
 201
 202 However, other tests that simply rely on basic parts of the core
 203 GIT working properly should not have that level of intimate
 204 knowledge of the core GIT internals.  If all the test scripts
 205 hardcoded the object IDs like t0000-basic.sh does, that defeats
 206 the purpose of t0000-basic.sh, which is to isolate that level of
 207 validation in one place.  Your test also ends up needing
 208 updating when such a change to the internal happens, so do _not_
 209 do it and leave the low level of validation to t0000-basic.sh.