xref: /aosp_15_r20/external/ltp/doc/old/User-Guidelines.asciidoc (revision 49cdfc7efb34551c7342be41a7384b9c40d7cab7)

LTP User Guidelines
===================

For compiling, installing and running the tests see `README.md`.
For running LTP network tests see `testcases/network/README.md`.

1. Library environment variables
--------------------------------

Following environment variables are expected to be set by LTP users. Therefore,
with some exceptions, they have 'LTP_' prefix. Environment variables with 'TST_'
prefix are used inside LTP shell API and should *not* be set by users.

|==============================================================================
| 'KCONFIG_PATH'        | The path to the kernel config file, (if not set, it tries
                          the usual paths '/boot/config-RELEASE' or '/proc/config.gz').
| 'KCONFIG_SKIP_CHECK'  | Skip kernel config check if variable set (not set by default).
| 'LTPROOT'             | Prefix for installed LTP.  **Should be always set**
                          as some tests need it for path to test data files
                          ('LTP_DATAROOT'). LTP is by default installed into '/opt/ltp'.
| 'LTP_COLORIZE_OUTPUT' | By default LTP colorizes it's output unless it's redirected
                          to a pipe or file.  Force colorized output behaviour:
                          'y' or '1': always colorize, 'n' or '0': never colorize.
| 'LTP_DEV'             | Path to the block device to be used
                          (C: '.needs_device = 1', shell: 'TST_NEEDS_DEVICE=1').
| 'LTP_SINGLE_FS_TYPE'  | Testing only - specifies filesystem instead all
                          supported (for tests with '.all_filesystems').
| 'LTP_DEV_FS_TYPE'     | Filesystem used for testing (default: 'ext2').
| 'LTP_TIMEOUT_MUL'     | Multiplies timeout, must be number >= 0.1 (> 1 is useful for
                          slow machines to avoid unexpected timeout).
                          Variable is also used in shell tests, but ceiled to int.
| 'LTP_RUNTIME_MUL'     | Multiplies maximal test iteration runtime. Tests
                          that run for more than a second or two are capped on
                          runtime. You can scale the default runtime both up
                          and down with this multiplier. NOTE: Not yet implemented
                          in shell API.
| 'LTP_VIRT_OVERRIDE'   | Overrides virtual machine detection in the test
                          library. Setting it to empty string tell the library
                          that system is not a virtual machine. Other possible
                          values are 'kvm', 'xen', 'zvm' and 'microsoft' that
                          describe different types supervisors.
| 'PATH'                | It's required to addjust path:
                          `PATH="$PATH:$LTPROOT/testcases/bin"`
| 'TMPDIR'              | Base directory for template directory (C: '.needs_tmpdir = 1'
                          and others, which imply it, shell: 'TST_NEEDS_TMPDIR=1').
                          Must be an absolute path (default: '/tmp').
| 'LTP_NO_CLEANUP'      | Disable running test cleanup (defined in 'TST_CLEANUP').
                          Shell API only.
| 'LTP_ENABLE_DEBUG'    | Enable debug info (value '1' or 'y').
|==============================================================================

2. Test execution time and timeout
----------------------------------

The limit on how long a test can run does compose of two parts max_runtime and
timeout. The limit does apply to a single test variant, that means for example
that tests that run for all available filesystems will apply this limit for a
single filesystem only.

The max_runtime is a cap on how long the run() function can take, for most
testcases this part is set to zero. For tests that do run for more than a
second or two the max_runtime has to be defined and the run() function has to
check actively how much runtime is left.

Test runtime can be scaled up and down with 'LTP_RUNTIME_MUL' environment
variable or set on a commandline by the '-I' parameter. Hoewever be vary that
setting the runtime too low will cause long running tests to exit prematurely
possibly before the have a chance actually test anyting.

The timeout part is a limit for the test setup and cleanup and also safety
margin for the runtime accounting. It's currently set to 30 seconds but may
change later. If your target machine is too slow it can be scaled up with the
'LTP_TIMEOUT_MUL' environment variable.