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 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 --long-tests::
  58         This causes additional long-running tests to be run (where
  59         available), for more exhaustive testing.
  60
  61
  62 Skipping Tests
  63 --------------
  64
  65 In some environments, certain tests have no way of succeeding
  66 due to platform limitation, such as lack of 'unzip' program, or
  67 filesystem that do not allow arbitrary sequence of non-NUL bytes
  68 as pathnames.
  69
  70 You should be able to say something like
  71
  72     $ GIT_SKIP_TESTS=t9200.8 sh ./t9200-git-cvsexport-commit.sh
  73
  74 and even:
  75
  76     $ GIT_SKIP_TESTS='t[0-4]??? t91?? t9200.8' make
  77
  78 to omit such tests.  The value of the environment variable is a
  79 SP separated list of patterns that tells which tests to skip,
  80 and either can match the "t[0-9]{4}" part to skip the whole
  81 test, or t[0-9]{4} followed by ".$number" to say which
  82 particular test to skip.
  83
  84 Note that some tests in the existing test suite rely on previous
  85 test item, so you cannot arbitrarily disable one and expect the
  86 remainder of test to check what the test originally was intended
  87 to check.
  88
  89
  90 Naming Tests
  91 ------------
  92
  93 The test files are named as:
  94
  95         tNNNN-commandname-details.sh
  96
  97 where N is a decimal digit.
  98
  99 First digit tells the family:
 100
 101         0 - the absolute basics and global stuff
 102         1 - the basic commands concerning database
 103         2 - the basic commands concerning the working tree
 104         3 - the other basic commands (e.g. ls-files)
 105         4 - the diff commands
 106         5 - the pull and exporting commands
 107         6 - the revision tree commands (even e.g. merge-base)
 108         7 - the porcelainish commands concerning the working tree
 109         8 - the porcelainish commands concerning forensics
 110         9 - the git tools
 111
 112 Second digit tells the particular command we are testing.
 113
 114 Third digit (optionally) tells the particular switch or group of switches
 115 we are testing.
 116
 117 If you create files under t/ directory (i.e. here) that is not
 118 the top-level test script, never name the file to match the above
 119 pattern.  The Makefile here considers all such files as the
 120 top-level test script and tries to run all of them.  A care is
 121 especially needed if you are creating a common test library
 122 file, similar to test-lib.sh, because such a library file may
 123 not be suitable for standalone execution.
 124
 125
 126 Writing Tests
 127 -------------
 128
 129 The test script is written as a shell script.  It should start
 130 with the standard "#!/bin/sh" with copyright notices, and an
 131 assignment to variable 'test_description', like this:
 132
 133         #!/bin/sh
 134         #
 135         # Copyright (c) 2005 Junio C Hamano
 136         #
 137
 138         test_description='xxx test (option --frotz)
 139
 140         This test registers the following structure in the cache
 141         and tries to run git-ls-files with option --frotz.'
 142
 143
 144 Source 'test-lib.sh'
 145 --------------------
 146
 147 After assigning test_description, the test script should source
 148 test-lib.sh like this:
 149
 150         . ./test-lib.sh
 151
 152 This test harness library does the following things:
 153
 154  - If the script is invoked with command line argument --help
 155    (or -h), it shows the test_description and exits.
 156
 157  - Creates an empty test directory with an empty .git/objects
 158    database and chdir(2) into it.  This directory is 't/trash directory'
 159    if you must know, but I do not think you care.
 160
 161  - Defines standard test helper functions for your scripts to
 162    use.  These functions are designed to make all scripts behave
 163    consistently when command line arguments --verbose (or -v),
 164    --debug (or -d), and --immediate (or -i) is given.
 165
 166
 167 End with test_done
 168 ------------------
 169
 170 Your script will be a sequence of tests, using helper functions
 171 from the test harness library.  At the end of the script, call
 172 'test_done'.
 173
 174
 175 Test harness library
 176 --------------------
 177
 178 There are a handful helper functions defined in the test harness
 179 library for your script to use.
 180
 181  - test_expect_success <message> <script>
 182
 183    This takes two strings as parameter, and evaluates the
 184    <script>.  If it yields success, test is considered
 185    successful.  <message> should state what it is testing.
 186
 187    Example:
 188
 189         test_expect_success \
 190             'git-write-tree should be able to write an empty tree.' \
 191             'tree=$(git-write-tree)'
 192
 193  - test_expect_failure <message> <script>
 194
 195    This is NOT the opposite of test_expect_success, but is used
 196    to mark a test that demonstrates a known breakage.  Unlike
 197    the usual test_expect_success tests, which say "ok" on
 198    success and "FAIL" on failure, this will say "FIXED" on
 199    success and "still broken" on failure.  Failures from these
 200    tests won't cause -i (immediate) to stop.
 201
 202  - test_debug <script>
 203
 204    This takes a single argument, <script>, and evaluates it only
 205    when the test script is started with --debug command line
 206    argument.  This is primarily meant for use during the
 207    development of a new test script.
 208
 209  - test_done
 210
 211    Your test script must have test_done at the end.  Its purpose
 212    is to summarize successes and failures in the test script and
 213    exit with an appropriate error code.
 214
 215  - test_tick
 216
 217    Make commit and tag names consistent by setting the author and
 218    committer times to defined stated.  Subsequent calls will
 219    advance the times by a fixed amount.
 220
 221  - test_commit <message> [<filename> [<contents>]]
 222
 223    Creates a commit with the given message, committing the given
 224    file with the given contents (default for both is to reuse the
 225    message string), and adds a tag (again reusing the message
 226    string as name).  Calls test_tick to make the SHA-1s
 227    reproducible.
 228
 229  - test_merge <message> <commit-or-tag>
 230
 231    Merges the given rev using the given message.  Like test_commit,
 232    creates a tag and calls test_tick before committing.
 233
 234 Tips for Writing Tests
 235 ----------------------
 236
 237 As with any programming projects, existing programs are the best
 238 source of the information.  However, do _not_ emulate
 239 t0000-basic.sh when writing your tests.  The test is special in
 240 that it tries to validate the very core of GIT.  For example, it
 241 knows that there will be 256 subdirectories under .git/objects/,
 242 and it knows that the object ID of an empty tree is a certain
 243 40-byte string.  This is deliberately done so in t0000-basic.sh
 244 because the things the very basic core test tries to achieve is
 245 to serve as a basis for people who are changing the GIT internal
 246 drastically.  For these people, after making certain changes,
 247 not seeing failures from the basic test _is_ a failure.  And
 248 such drastic changes to the core GIT that even changes these
 249 otherwise supposedly stable object IDs should be accompanied by
 250 an update to t0000-basic.sh.
 251
 252 However, other tests that simply rely on basic parts of the core
 253 GIT working properly should not have that level of intimate
 254 knowledge of the core GIT internals.  If all the test scripts
 255 hardcoded the object IDs like t0000-basic.sh does, that defeats
 256 the purpose of t0000-basic.sh, which is to isolate that level of
 257 validation in one place.  Your test also ends up needing
 258 updating when such a change to the internal happens, so do _not_
 259 do it and leave the low level of validation to t0000-basic.sh.