NAME

     kyua debug — Executes a single test case with facilities for debugging

SYNOPSIS

     kyua debug [--build-root path] [--kyuafile file] [--stdout path] [--stderr path] test_case

DESCRIPTION

     The kyua debug command provides a mechanism to execute a single test case bypassing some of
     the Kyua infrastructure and allowing the user to poke into the execution behavior of the
     test.

     The test case to run is selected by providing a test filter, described below in Test
     filters, that matches a single test case.  The test case is executed and its result is
     printed as the last line of the output of the tool.

     The test executed by kyua debug is run under a controlled environment as described in Test
     isolation.

     At the moment, the kyua debug command allows the following aspects of a test case execution
     to be tweaked:

     •   Redirection of the test case's stdout and stderr to the console (the default) or to
         arbitrary files.  See the --stdout and --stderr options below.

     The following subcommand options are recognized:

     --build-root path
         Specifies the build root in which to find the test programs referenced by the Kyuafile,
         if different from the Kyuafile's directory.  See Build directories below for more
         information.

     --kyuafile file, -k file
         Specifies the Kyuafile to process.  Defaults to Kyuafile file in the current directory.

     --stderr path
         Specifies the file to which to send the standard error of the test program's body.  The
         default is /dev/stderr, which is a special character device that redirects the output to
         standard error on the console.

     --stdout path
         Specifies the file to which to send the standard output of the test program's body.  The
         default is /dev/stdout, which is a special character device that redirects the output to
         standard output on the console.

     For example, consider the following Kyua session:

           $ kyua test
           kernel/fs:mkdir  ->  passed
           kernel/fs:rmdir  ->  failed: Invalid argument

           1/2 passed (1 failed)

     At this point, we do not have a lot of information regarding the failure of the
     ‘kernel/fs:rmdir’ test.  We can run this test through the kyua debug command to inspect its
     output a bit closer, hoping that the test case is kind enough to log its progress:

           $ kyua debug kernel/fs:rmdir
           Trying rmdir('foo')
           Trying rmdir(NULL)
           kernel/fs:rmdir  ->  failed: Invalid argument

     Luckily, the offending test case was printing status lines as it progressed, so we could see
     the last attempted call and we can know match the failure message to the problem.

   Build directories
     Build directories (or object directories, target directories, product directories, etc.) is
     the concept that allows a developer to keep the source tree clean from build products by
     asking the build system to place such build products under a separate subtree.

     Most build systems today support build directories.  For example, the GNU Automake/Autoconf
     build system exposes such concept when invoked as follows:

           $ cd my-project-1.0
           $ mkdir build
           $ cd build
           $ ../configure
           $ make

     Under such invocation, all the results of the build are left in the my-project-1.0/build/
     subdirectory while maintaining the contents of my-project-1.0/ intact.

     Because build directories are an integral part of most build systems, and because they are a
     tool that developers use frequently, kyua debug supports build directories too.  This
     manifests in the form of kyua debug being able to run tests from build directories while
     reading the (often immutable) test suite definition from the source tree.

     One important property of build directories is that they follow (or need to follow) the
     exact same layout as the source tree.  For example, consider the following directory
     listings:

           src/Kyuafile
           src/bin/ls/
           src/bin/ls/Kyuafile
           src/bin/ls/ls.c
           src/bin/ls/ls_test.c
           src/sbin/su/
           src/sbin/su/Kyuafile
           src/sbin/su/su.c
           src/sbin/su/su_test.c

           obj/bin/ls/
           obj/bin/ls/ls*
           obj/bin/ls/ls_test*
           obj/sbin/su/
           obj/sbin/su/su*
           obj/sbin/su/su_test*

     Note how the directory layout within src/ matches that of obj/.  The src/ directory contains
     only source files and the definition of the test suite (the Kyuafiles), while the obj/
     directory contains only the binaries generated during a build.

     All commands that deal with the workspace support the --build-root path option.  When this
     option is provided, the directory specified by the option is considered to be the root of
     the build directory.  For example, considering our previous fake tree layout, we could
     invoke kyua debug as any of the following:

           $ kyua debug --kyuafile=src/Kyuafile --build-root=obj
           $ cd src && kyua debug --build-root=../obj

   Test filters
     A test filter is a string that is used to match test cases or test programs in a test suite.
     Filters have the following form:

           test_program_name[:test_case_name]

     Where ‘test_program_name’ is the name of a test program or a subdirectory in the test suite,
     and ‘test_case_name’ is the name of a test case.

   Test isolation
     The test programs and test cases run by kyua debug are all executed in a deterministic
     environment.  This known, clean environment serves to make the test execution as
     reproducible as possible and also to prevent clashes between tests that may, for example,
     create auxiliary files with overlapping names.

     For plain test programs and for TAP test programs, the whole test program is run under a
     single instance of the environment described in this page.  For ATF test programs (see
     atf(7)), each individual test case and test cleanup routine are executed in separate
     environments.

     Process space
         Each test is executed in an independent processes.  Corollary: the test can do whatever
         it wants to the current process (such as modify global variables) without having to undo
         such changes.

     Session and process group
         The test is executed in its own session and its own process group.  There is no
         controlling terminal attached to the session.

         Should the test spawn any children, the children should maintain the same session and
         process group.  Modifying any of these settings prevents kyua debug from being able to
         kill any stray subprocess as part of the cleanup phase.  If modifying these settings is
         necessary, or if any subprocess started by the test decides to use a different process
         group or session, it is the responsibility of the test to ensure those subprocesses are
         forcibly terminated during cleanup.

     Work directory
         The test is executed in a temporary directory automatically created by the runtime
         engine.  Corollary: the test can write to its current directory without needing to clean
         any files and/or directories it creates.  The runtime engine takes care to recursively
         delete the temporary directories after the execution of a test case.  Any file systems
         mounted within the temporary directory are also unmounted.

     Home directory
         The HOME environment variable is set to the absolute path of the work directory.

     Umask
         The value of the umask is set to 0022.

     Environment
         The LANG, LC_ALL, LC_COLLATE, LC_CTYPE, LC_MESSAGES, LC_MONETARY, LC_NUMERIC and LC_TIME
         variables are unset.

         The TZ variable is set to ‘UTC’.

         The TMPDIR variable is set to the absolute path of the work directory.  This is to
         prevent the test from mistakenly using a temporary directory outside of the
         automatically-managed work directory, should the test use the mktemp(3) familiy of
         functions.

     Process limits
         The maximum soft core size limit is raised to its corresponding hard limit.  This is a
         simple, best-effort attempt at allowing tests to dump core for further diagnostic
         purposes.

     Configuration varibles
         The test engine may pass run-time configuration variables to the test program via the
         environment.  The name of the configuration variable is prefixed with ‘TEST_ENV_’ so
         that a configuration variable of the form ‘foo=bar’ becomes accessible in the
         environment as ‘TEST_ENV_foo=bar’.

EXIT STATUS

     The kyua debug command returns 0 if the test case passes or 1 if the test case fails.

     Additional exit codes may be returned as described in kyua(1).

SEE ALSO

     kyua(1), kyuafile(5)