1 lit - LLVM Integrated Tester 2 ============================ 3 4 SYNOPSIS 5 -------- 6 7 :program:`lit` [*options*] [*tests*] 8 9 DESCRIPTION 10 ----------- 11 12 :program:`lit` is a portable tool for executing LLVM and Clang style test 13 suites, summarizing their results, and providing indication of failures. 14 :program:`lit` is designed to be a lightweight testing tool with as simple a 15 user interface as possible. 16 17 :program:`lit` should be run with one or more *tests* to run specified on the 18 command line. Tests can be either individual test files or directories to 19 search for tests (see :ref:`test-discovery`). 20 21 Each specified test will be executed (potentially in parallel) and once all 22 tests have been run :program:`lit` will print summary information on the number 23 of tests which passed or failed (see :ref:`test-status-results`). The 24 :program:`lit` program will execute with a non-zero exit code if any tests 25 fail. 26 27 By default :program:`lit` will use a succinct progress display and will only 28 print summary information for test failures. See :ref:`output-options` for 29 options controlling the :program:`lit` progress display and output. 30 31 :program:`lit` also includes a number of options for controlling how tests are 32 executed (specific features may depend on the particular test format). See 33 :ref:`execution-options` for more information. 34 35 Finally, :program:`lit` also supports additional options for only running a 36 subset of the options specified on the command line, see 37 :ref:`selection-options` for more information. 38 39 Users interested in the :program:`lit` architecture or designing a 40 :program:`lit` testing implementation should see :ref:`lit-infrastructure`. 41 42 GENERAL OPTIONS 43 --------------- 44 45 .. option:: -h, --help 46 47 Show the :program:`lit` help message. 48 49 .. option:: -j N, --threads=N 50 51 Run ``N`` tests in parallel. By default, this is automatically chosen to 52 match the number of detected available CPUs. 53 54 .. option:: --config-prefix=NAME 55 56 Search for :file:`{NAME}.cfg` and :file:`{NAME}.site.cfg` when searching for 57 test suites, instead of :file:`lit.cfg` and :file:`lit.site.cfg`. 58 59 .. option:: --param NAME, --param NAME=VALUE 60 61 Add a user defined parameter ``NAME`` with the given ``VALUE`` (or the empty 62 string if not given). The meaning and use of these parameters is test suite 63 dependent. 64 65 .. _output-options: 66 67 OUTPUT OPTIONS 68 -------------- 69 70 .. option:: -q, --quiet 71 72 Suppress any output except for test failures. 73 74 .. option:: -s, --succinct 75 76 Show less output, for example don't show information on tests that pass. 77 78 .. option:: -v, --verbose 79 80 Show more information on test failures, for example the entire test output 81 instead of just the test result. 82 83 .. option:: --no-progress-bar 84 85 Do not use curses based progress bar. 86 87 .. _execution-options: 88 89 EXECUTION OPTIONS 90 ----------------- 91 92 .. option:: --path=PATH 93 94 Specify an additional ``PATH`` to use when searching for executables in tests. 95 96 .. option:: --vg 97 98 Run individual tests under valgrind (using the memcheck tool). The 99 ``--error-exitcode`` argument for valgrind is used so that valgrind failures 100 will cause the program to exit with a non-zero status. 101 102 When this option is enabled, :program:`lit` will also automatically provide a 103 "``valgrind``" feature that can be used to conditionally disable (or expect 104 failure in) certain tests. 105 106 .. option:: --vg-arg=ARG 107 108 When :option:`--vg` is used, specify an additional argument to pass to 109 :program:`valgrind` itself. 110 111 .. option:: --vg-leak 112 113 When :option:`--vg` is used, enable memory leak checks. When this option is 114 enabled, :program:`lit` will also automatically provide a "``vg_leak``" 115 feature that can be used to conditionally disable (or expect failure in) 116 certain tests. 117 118 .. option:: --time-tests 119 120 Track the wall time individual tests take to execute and includes the results 121 in the summary output. This is useful for determining which tests in a test 122 suite take the most time to execute. Note that this option is most useful 123 with ``-j 1``. 124 125 .. _selection-options: 126 127 SELECTION OPTIONS 128 ----------------- 129 130 .. option:: --max-tests=N 131 132 Run at most ``N`` tests and then terminate. 133 134 .. option:: --max-time=N 135 136 Spend at most ``N`` seconds (approximately) running tests and then terminate. 137 138 .. option:: --shuffle 139 140 Run the tests in a random order. 141 142 ADDITIONAL OPTIONS 143 ------------------ 144 145 .. option:: --debug 146 147 Run :program:`lit` in debug mode, for debugging configuration issues and 148 :program:`lit` itself. 149 150 .. option:: --show-suites 151 152 List the discovered test suites and exit. 153 154 .. option:: --show-tests 155 156 List all of the the discovered tests and exit. 157 158 EXIT STATUS 159 ----------- 160 161 :program:`lit` will exit with an exit code of 1 if there are any FAIL or XPASS 162 results. Otherwise, it will exit with the status 0. Other exit codes are used 163 for non-test related failures (for example a user error or an internal program 164 error). 165 166 .. _test-discovery: 167 168 TEST DISCOVERY 169 -------------- 170 171 The inputs passed to :program:`lit` can be either individual tests, or entire 172 directories or hierarchies of tests to run. When :program:`lit` starts up, the 173 first thing it does is convert the inputs into a complete list of tests to run 174 as part of *test discovery*. 175 176 In the :program:`lit` model, every test must exist inside some *test suite*. 177 :program:`lit` resolves the inputs specified on the command line to test suites 178 by searching upwards from the input path until it finds a :file:`lit.cfg` or 179 :file:`lit.site.cfg` file. These files serve as both a marker of test suites 180 and as configuration files which :program:`lit` loads in order to understand 181 how to find and run the tests inside the test suite. 182 183 Once :program:`lit` has mapped the inputs into test suites it traverses the 184 list of inputs adding tests for individual files and recursively searching for 185 tests in directories. 186 187 This behavior makes it easy to specify a subset of tests to run, while still 188 allowing the test suite configuration to control exactly how tests are 189 interpreted. In addition, :program:`lit` always identifies tests by the test 190 suite they are in, and their relative path inside the test suite. For 191 appropriately configured projects, this allows :program:`lit` to provide 192 convenient and flexible support for out-of-tree builds. 193 194 .. _test-status-results: 195 196 TEST STATUS RESULTS 197 ------------------- 198 199 Each test ultimately produces one of the following six results: 200 201 **PASS** 202 203 The test succeeded. 204 205 **XFAIL** 206 207 The test failed, but that is expected. This is used for test formats which allow 208 specifying that a test does not currently work, but wish to leave it in the test 209 suite. 210 211 **XPASS** 212 213 The test succeeded, but it was expected to fail. This is used for tests which 214 were specified as expected to fail, but are now succeeding (generally because 215 the feature they test was broken and has been fixed). 216 217 **FAIL** 218 219 The test failed. 220 221 **UNRESOLVED** 222 223 The test result could not be determined. For example, this occurs when the test 224 could not be run, the test itself is invalid, or the test was interrupted. 225 226 **UNSUPPORTED** 227 228 The test is not supported in this environment. This is used by test formats 229 which can report unsupported tests. 230 231 Depending on the test format tests may produce additional information about 232 their status (generally only for failures). See the :ref:`output-options` 233 section for more information. 234 235 .. _lit-infrastructure: 236 237 LIT INFRASTRUCTURE 238 ------------------ 239 240 This section describes the :program:`lit` testing architecture for users interested in 241 creating a new :program:`lit` testing implementation, or extending an existing one. 242 243 :program:`lit` proper is primarily an infrastructure for discovering and running 244 arbitrary tests, and to expose a single convenient interface to these 245 tests. :program:`lit` itself doesn't know how to run tests, rather this logic is 246 defined by *test suites*. 247 248 TEST SUITES 249 ~~~~~~~~~~~ 250 251 As described in :ref:`test-discovery`, tests are always located inside a *test 252 suite*. Test suites serve to define the format of the tests they contain, the 253 logic for finding those tests, and any additional information to run the tests. 254 255 :program:`lit` identifies test suites as directories containing ``lit.cfg`` or 256 ``lit.site.cfg`` files (see also :option:`--config-prefix`). Test suites are 257 initially discovered by recursively searching up the directory hierarchy for 258 all the input files passed on the command line. You can use 259 :option:`--show-suites` to display the discovered test suites at startup. 260 261 Once a test suite is discovered, its config file is loaded. Config files 262 themselves are Python modules which will be executed. When the config file is 263 executed, two important global variables are predefined: 264 265 **lit** 266 267 The global **lit** configuration object (a *LitConfig* instance), which defines 268 the builtin test formats, global configuration parameters, and other helper 269 routines for implementing test configurations. 270 271 **config** 272 273 This is the config object (a *TestingConfig* instance) for the test suite, 274 which the config file is expected to populate. The following variables are also 275 available on the *config* object, some of which must be set by the config and 276 others are optional or predefined: 277 278 **name** *[required]* The name of the test suite, for use in reports and 279 diagnostics. 280 281 **test_format** *[required]* The test format object which will be used to 282 discover and run tests in the test suite. Generally this will be a builtin test 283 format available from the *lit.formats* module. 284 285 **test_source_root** The filesystem path to the test suite root. For out-of-dir 286 builds this is the directory that will be scanned for tests. 287 288 **test_exec_root** For out-of-dir builds, the path to the test suite root inside 289 the object directory. This is where tests will be run and temporary output files 290 placed. 291 292 **environment** A dictionary representing the environment to use when executing 293 tests in the suite. 294 295 **suffixes** For **lit** test formats which scan directories for tests, this 296 variable is a list of suffixes to identify test files. Used by: *ShTest*. 297 298 **substitutions** For **lit** test formats which substitute variables into a test 299 script, the list of substitutions to perform. Used by: *ShTest*. 300 301 **unsupported** Mark an unsupported directory, all tests within it will be 302 reported as unsupported. Used by: *ShTest*. 303 304 **parent** The parent configuration, this is the config object for the directory 305 containing the test suite, or None. 306 307 **root** The root configuration. This is the top-most :program:`lit` configuration in 308 the project. 309 310 **on_clone** The config is actually cloned for every subdirectory inside a test 311 suite, to allow local configuration on a per-directory basis. The *on_clone* 312 variable can be set to a Python function which will be called whenever a 313 configuration is cloned (for a subdirectory). The function should takes three 314 arguments: (1) the parent configuration, (2) the new configuration (which the 315 *on_clone* function will generally modify), and (3) the test path to the new 316 directory being scanned. 317 318 **pipefail** Normally a test using a shell pipe fails if any of the commands 319 on the pipe fail. If this is not desired, setting this variable to false 320 makes the test fail only if the last command in the pipe fails. 321 322 TEST DISCOVERY 323 ~~~~~~~~~~~~~~ 324 325 Once test suites are located, :program:`lit` recursively traverses the source 326 directory (following *test_source_root*) looking for tests. When :program:`lit` 327 enters a sub-directory, it first checks to see if a nested test suite is 328 defined in that directory. If so, it loads that test suite recursively, 329 otherwise it instantiates a local test config for the directory (see 330 :ref:`local-configuration-files`). 331 332 Tests are identified by the test suite they are contained within, and the 333 relative path inside that suite. Note that the relative path may not refer to 334 an actual file on disk; some test formats (such as *GoogleTest*) define 335 "virtual tests" which have a path that contains both the path to the actual 336 test file and a subpath to identify the virtual test. 337 338 .. _local-configuration-files: 339 340 LOCAL CONFIGURATION FILES 341 ~~~~~~~~~~~~~~~~~~~~~~~~~ 342 343 When :program:`lit` loads a subdirectory in a test suite, it instantiates a 344 local test configuration by cloning the configuration for the parent direction 345 --- the root of this configuration chain will always be a test suite. Once the 346 test configuration is cloned :program:`lit` checks for a *lit.local.cfg* file 347 in the subdirectory. If present, this file will be loaded and can be used to 348 specialize the configuration for each individual directory. This facility can 349 be used to define subdirectories of optional tests, or to change other 350 configuration parameters --- for example, to change the test format, or the 351 suffixes which identify test files. 352 353 TEST RUN OUTPUT FORMAT 354 ~~~~~~~~~~~~~~~~~~~~~~ 355 356 The :program:`lit` output for a test run conforms to the following schema, in 357 both short and verbose modes (although in short mode no PASS lines will be 358 shown). This schema has been chosen to be relatively easy to reliably parse by 359 a machine (for example in buildbot log scraping), and for other tools to 360 generate. 361 362 Each test result is expected to appear on a line that matches: 363 364 .. code-block:: none 365 366 <result code>: <test name> (<progress info>) 367 368 where ``<result-code>`` is a standard test result such as PASS, FAIL, XFAIL, 369 XPASS, UNRESOLVED, or UNSUPPORTED. The performance result codes of IMPROVED and 370 REGRESSED are also allowed. 371 372 The ``<test name>`` field can consist of an arbitrary string containing no 373 newline. 374 375 The ``<progress info>`` field can be used to report progress information such 376 as (1/300) or can be empty, but even when empty the parentheses are required. 377 378 Each test result may include additional (multiline) log information in the 379 following format: 380 381 .. code-block:: none 382 383 <log delineator> TEST '(<test name>)' <trailing delineator> 384 ... log message ... 385 <log delineator> 386 387 where ``<test name>`` should be the name of a preceding reported test, ``<log 388 delineator>`` is a string of "*" characters *at least* four characters long 389 (the recommended length is 20), and ``<trailing delineator>`` is an arbitrary 390 (unparsed) string. 391 392 The following is an example of a test run output which consists of four tests A, 393 B, C, and D, and a log message for the failing test C: 394 395 .. code-block:: none 396 397 PASS: A (1 of 4) 398 PASS: B (2 of 4) 399 FAIL: C (3 of 4) 400 ******************** TEST 'C' FAILED ******************** 401 Test 'C' failed as a result of exit code 1. 402 ******************** 403 PASS: D (4 of 4) 404 405 LIT EXAMPLE TESTS 406 ~~~~~~~~~~~~~~~~~ 407 408 The :program:`lit` distribution contains several example implementations of 409 test suites in the *ExampleTests* directory. 410 411 SEE ALSO 412 -------- 413 414 valgrind(1) 415
