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NAME

       lit - LLVM Integrated Tester

SYNOPSIS

       lit [options] [tests]

DESCRIPTION

       lit  is  a portable tool for executing LLVM and Clang style test suites, summarizing their
       results, and providing indication of failures.   lit  is  designed  to  be  a  lightweight
       testing tool with as simple a user interface as possible.

       lit  should be run with one or more tests to run specified on the command line.  Tests can
       be either individual test files or directories to search for tests (see TEST DISCOVERY).

       Each specified test will be executed (potentially in parallel) and  once  all  tests  have
       been  run lit will print summary information on the number of tests which passed or failed
       (see TEST STATUS RESULTS).  The lit program will execute with a non-zero exit code if  any
       tests fail.

       By  default  lit  will  use  a  succinct  progress  display  and  will  only print summary
       information for test failures.   See  OUTPUT  OPTIONS  for  options  controlling  the  lit
       progress display and output.

       lit  also  includes  a  number of options for controlling how tests are executed (specific
       features may depend on the particular  test  format).   See  EXECUTION  OPTIONS  for  more
       information.

       Finally,  lit  also  supports  additional options for only running a subset of the options
       specified on the command line, see SELECTION OPTIONS for more information.

       Users interested in the lit architecture or designing a lit testing implementation  should
       see LIT INFRASTRUCTURE.

GENERAL OPTIONS

       -h, --help
              Show the lit help message.

       -j N, --threads=N
              Run  N  tests  in  parallel.  By default, this is automatically chosen to match the
              number of detected available CPUs.

       --config-prefix=NAME
              Search for NAME.cfg and NAME.site.cfg when searching for test  suites,  instead  of
              lit.cfg and lit.site.cfg.

       --param NAME, --param NAME=VALUE
              Add  a user defined parameter NAME with the given VALUE (or the empty string if not
              given).  The meaning and use of these parameters is test suite dependent.

OUTPUT OPTIONS

       -q, --quiet
              Suppress any output except for test failures.

       -s, --succinct
              Show less output, for example don't show information on tests that pass.

       -v, --verbose
              Show more information on test failures, for example the entire test output  instead
              of just the test result.

       --no-progress-bar
              Do not use curses based progress bar.

EXECUTION OPTIONS

       --path=PATH
              Specify an additional PATH to use when searching for executables in tests.

       --vg   Run   individual   tests   under   valgrind   (using   the   memcheck  tool).   The
              --error-exitcode argument for valgrind is used so that valgrind failures will cause
              the program to exit with a non-zero status.

              When  this  option  is  enabled,  lit  will also automatically provide a "valgrind"
              feature that can be used to conditionally disable (or expect  failure  in)  certain
              tests.

       --vg-arg=ARG
              When --vg is used, specify an additional argument to pass to valgrind itself.

       --vg-leak
              When  --vg  is  used,  enable memory leak checks.  When this option is enabled, lit
              will  also  automatically  provide  a  "vg_leak"  feature  that  can  be  used   to
              conditionally disable (or expect failure in) certain tests.

       --time-tests
              Track  the  wall  time individual tests take to execute and includes the results in
              the summary output.  This is useful for determining which tests  in  a  test  suite
              take the most time to execute.  Note that this option is most useful with -j 1.

SELECTION OPTIONS

       --max-tests=N
              Run at most N tests and then terminate.

       --max-time=N
              Spend at most N seconds (approximately) running tests and then terminate.

       --shuffle
              Run the tests in a random order.

ADDITIONAL OPTIONS

       --debug
              Run lit in debug mode, for debugging configuration issues and lit itself.

       --show-suites
              List the discovered test suites and exit.

       --show-tests
              List all of the the discovered tests and exit.

EXIT STATUS

       lit  will  exit with an exit code of 1 if there are any FAIL or XPASS results.  Otherwise,
       it will exit with the status 0.  Other exit codes are used for non-test  related  failures
       (for example a user error or an internal program error).

TEST DISCOVERY

       The  inputs  passed  to  lit  can  be  either  individual  tests, or entire directories or
       hierarchies of tests to run.  When lit starts up, the first thing it does is  convert  the
       inputs into a complete list of tests to run as part of test discovery.

       In  the  lit model, every test must exist inside some test suite.  lit resolves the inputs
       specified on the command line to test suites by searching  upwards  from  the  input  path
       until it finds a lit.cfg or lit.site.cfg file.  These files serve as both a marker of test
       suites and as configuration files which lit loads in order to understand how to  find  and
       run the tests inside the test suite.

       Once  lit  has  mapped  the inputs into test suites it traverses the list of inputs adding
       tests for individual files and recursively searching for tests in directories.

       This behavior makes it easy to specify a subset of tests to run, while still allowing  the
       test  suite  configuration to control exactly how tests are interpreted.  In addition, lit
       always identifies tests by the test suite they are in, and their relative path inside  the
       test  suite.  For appropriately configured projects, this allows lit to provide convenient
       and flexible support for out-of-tree builds.

TEST STATUS RESULTS

       Each test ultimately produces one of the following six results:

       PASS
          The test succeeded.

       XFAIL
          The test failed, but that is expected.  This is  used  for  test  formats  which  allow
          specifying that a test does not currently work, but wish to leave it in the test suite.

       XPASS
          The  test  succeeded,  but  it was expected to fail.  This is used for tests which were
          specified as expected to fail, but are now succeeding (generally  because  the  feature
          they test was broken and has been fixed).

       FAIL
          The test failed.

       UNRESOLVED
          The  test result could not be determined.  For example, this occurs when the test could
          not be run, the test itself is invalid, or the test was interrupted.

       UNSUPPORTED
          The test is not supported in this environment.  This is used by test formats which  can
          report unsupported tests.

       Depending  on  the test format tests may produce additional information about their status
       (generally only for failures).  See the OUTPUT OPTIONS section for more information.

LIT INFRASTRUCTURE

       This section describes the lit testing architecture for users interested in creating a new
       lit testing implementation, or extending an existing one.

       lit proper is primarily an infrastructure for discovering and running arbitrary tests, and
       to expose a single convenient interface to these tests. lit itself doesn't know how to run
       tests, rather this logic is defined by test suites.

   TEST SUITES
       As described in TEST DISCOVERY, tests are always located inside a test suite.  Test suites
       serve to define the format of the tests they contain, the logic for finding  those  tests,
       and any additional information to run the tests.

       lit  identifies  test  suites as directories containing lit.cfg or lit.site.cfg files (see
       also --config-prefix).  Test suites are initially discovered by recursively  searching  up
       the  directory  hierarchy for all the input files passed on the command line.  You can use
       --show-suites to display the discovered test suites at startup.

       Once a test suite is discovered, its config file is loaded.  Config files  themselves  are
       Python  modules  which  will be executed.  When the config file is executed, two important
       global variables are predefined:

       lit
          The global lit configuration object (a LitConfig instance), which defines  the  builtin
          test   formats,   global  configuration  parameters,  and  other  helper  routines  for
          implementing test configurations.

       config
          This is the config object (a TestingConfig instance) for  the  test  suite,  which  the
          config file is expected to populate.  The following variables are also available on the
          config object, some of which must be set by the  config  and  others  are  optional  or
          predefined:

          name [required] The name of the test suite, for use in reports and diagnostics.

          test_format  [required]  The  test format object which will be used to discover and run
          tests in the test suite.  Generally this will be a builtin test format  available  from
          the lit.formats module.

          test_source_root  The  filesystem  path  to the test suite root.  For out-of-dir builds
          this is the directory that will be scanned for tests.

          test_exec_root For out-of-dir builds, the path to the test suite root inside the object
          directory.  This is where tests will be run and temporary output files placed.

          environment  A  dictionary  representing the environment to use when executing tests in
          the suite.

          suffixes For lit test formats which scan directories for tests, this variable is a list
          of suffixes to identify test files.  Used by: ShTest.

          substitutions  For  lit test formats which substitute variables into a test script, the
          list of substitutions to perform.  Used by: ShTest.

          unsupported Mark an unsupported directory, all tests within  it  will  be  reported  as
          unsupported.  Used by: ShTest.

          parent The parent configuration, this is the config object for the directory containing
          the test suite, or None.

          root The root configuration.  This is the top-most lit configuration in the project.

          on_clone The config is actually cloned for every subdirectory inside a test  suite,  to
          allow  local  configuration on a per-directory basis.  The on_clone variable can be set
          to a Python function which will be called whenever a configuration  is  cloned  (for  a
          subdirectory).    The   function   should   takes   three  arguments:  (1)  the  parent
          configuration, (2) the new configuration (which the on_clone  function  will  generally
          modify), and (3) the test path to the new directory being scanned.

          pipefail  Normally  a  test using a shell pipe fails if any of the commands on the pipe
          fail. If this is not desired, setting this variable to false makes the test  fail  only
          if the last command in the pipe fails.

   TEST DISCOVERY
       Once  test  suites  are located, lit recursively traverses the source directory (following
       test_source_root) looking for tests.  When lit enters a sub-directory, it first checks  to
       see  if a nested test suite is defined in that directory.  If so, it loads that test suite
       recursively, otherwise it instantiates a local test config for the  directory  (see  LOCAL
       CONFIGURATION FILES).

       Tests  are  identified  by the test suite they are contained within, and the relative path
       inside that suite.  Note that the relative path may not refer to an actual file  on  disk;
       some  test  formats  (such  as  GoogleTest)  define "virtual tests" which have a path that
       contains both the path to the actual test file and a subpath to identify the virtual test.

   LOCAL CONFIGURATION FILES
       When lit loads a subdirectory in a test suite, it instantiates a local test  configuration
       by  cloning  the configuration for the parent direction --- the root of this configuration
       chain will always be a test suite.  Once the test configuration is cloned lit checks for a
       lit.local.cfg  file  in the subdirectory.  If present, this file will be loaded and can be
       used to specialize the configuration for each individual directory.  This facility can  be
       used  to  define  subdirectories  of  optional  tests,  or  to  change other configuration
       parameters --- for example, to change the test format, or the suffixes which identify test
       files.

   TEST RUN OUTPUT FORMAT
       The  lit output for a test run conforms to the following schema, in both short and verbose
       modes (although in short mode no PASS lines will be shown).  This schema has  been  chosen
       to  be  relatively  easy  to  reliably  parse  by  a  machine (for example in buildbot log
       scraping), and for other tools to generate.

       Each test result is expected to appear on a line that matches:

          <result code>: <test name> (<progress info>)

       where <result-code>  is  a  standard  test  result  such  as  PASS,  FAIL,  XFAIL,  XPASS,
       UNRESOLVED,  or  UNSUPPORTED.   The performance result codes of IMPROVED and REGRESSED are
       also allowed.

       The <test name> field can consist of an arbitrary string containing no newline.

       The <progress info> field can be used to report progress information such  as  (1/300)  or
       can be empty, but even when empty the parentheses are required.

       Each  test  result  may  include  additional  (multiline) log information in the following
       format:

          <log delineator> TEST '(<test name>)' <trailing delineator>
          ... log message ...
          <log delineator>

       where <test name> should be the name of a preceding reported test, <log delineator>  is  a
       string of "*" characters at least four characters long (the recommended length is 20), and
       <trailing delineator> is an arbitrary (unparsed) string.

       The following is an example of a test run output which consists of four tests A, B, C, and
       D, and a log message for the failing test C:

          PASS: A (1 of 4)
          PASS: B (2 of 4)
          FAIL: C (3 of 4)
          ******************** TEST 'C' FAILED ********************
          Test 'C' failed as a result of exit code 1.
          ********************
          PASS: D (4 of 4)

   LIT EXAMPLE TESTS
       The  lit  distribution  contains  several  example  implementations  of test suites in the
       ExampleTests directory.

SEE ALSO

       valgrind(1)

AUTHOR

       Maintained by The LLVM Team (http://llvm.org/).

COPYRIGHT

       2003-2014, LLVM Project