Signed-off-by: Brenda J. Butler <>
 tools/testing/selftests/tc-testing/README   | 173 +++++++++++++++++++++++++---
 tools/testing/selftests/tc-testing/TODO.txt |  25 +++-
 2 files changed, 179 insertions(+), 19 deletions(-)

diff --git a/tools/testing/selftests/tc-testing/README 
index 970ff294fec8..3a0336782d2d 100644
--- a/tools/testing/selftests/tc-testing/README
+++ b/tools/testing/selftests/tc-testing/README
@@ -14,11 +14,11 @@ REQUIREMENTS
 *  The kernel must have network namespace support
-*   The kernel must have veth support available, as a veth pair is created
+*  The kernel must have veth support available, as a veth pair is created
    prior to running the tests.
-*  All tc-related features must be built in or available as modules.
-   To check what is required in current setup run:
+*  All tc-related features being tested must be built in or available as
+   modules.  To check what is required in current setup run:
    ./ -c
@@ -44,10 +44,13 @@ using the -p option when running tdc:
-To use tdc, root privileges are required. tdc will not run otherwise.
+To use tdc, root privileges are required.  This is because the
+commands being tested must be run as root.  The code that enforces
+execution by root uid has been moved into a plugin (see PLUGIN
-All tests are executed inside a network namespace to prevent conflicts
-within the host.
+If nsPlugin is linked, all tests are executed inside a network
+namespace to prevent conflicts within the host.
 Running tdc without any arguments will run all tests. Refer to the section
 on command line arguments for more information, or run:
@@ -59,6 +62,33 @@ output captured from the failing test will be printed 
immediately following
 the failed test in the TAP output.
+One run of tests is considered a "test suite" (this will be refined in the
+future).  A test suite has one or more test cases in it.
+A test case has four stages:
+  - setup
+  - execute
+  - verify
+  - teardown
+The setup and teardown stages can run zero or more commands.  The setup
+stage does some setup if the test needs it.  The teardown stage undoes
+the setup and returns the system to a "neutral" state so any other test
+can be run next.  These two stages require any commands run to return
+success, but do not otherwise verify the results.
+The execute and verify stages each run one command.  The execute stage
+tests the return code against one or more acceptable values.  The
+verify stage checks the return code for success, and also compares
+the stdout with a regular expression.
+Each of the commands in any stage will run in a shell instance.
@@ -70,23 +100,132 @@ executed as part of the test. More will be added as test 
cases require.
        $TC qdisc add dev $DEV1 ingress
+The NAMES values are used to substitute into the commands in the test cases.
 Run -h to see the full list of available arguments.
--p PATH           Specify the tc executable located at PATH to be used on this
-                  test run
--c                Show the available test case categories in this test file
--c CATEGORY       Run only tests that belong to CATEGORY
--f FILE           Read test cases from the JSON file named FILE
--l [CATEGORY]     List all test cases in the JSON file. If CATEGORY is
-                  specified, list test cases matching that category.
--s ID             Show the test case matching ID
--e ID             Execute the test case identified by ID
--i                Generate unique ID numbers for test cases with no existing
-                  ID number
+usage: [-h] [-p PATH] [-D DIR [DIR ...]] [-f FILE [FILE ...]]
+              [-c [CATG [CATG ...]]] [-e ID [ID ...]] [-l] [-s] [-i] [-v]
+              [-d DEVICE] [-n NS] [-V]
+Linux TC unit tests
+optional arguments:
+  -h, --help            show this help message and exit
+  -p PATH, --path PATH  The full path to the tc executable to use
+  -v, --verbose         Show the commands that are being run
+  -d DEVICE, --device DEVICE
+                        Execute the test case in flower category
+  select which test cases: files plus directories; filtered by categories
+  plus testids
+  -D DIR [DIR ...], --directory DIR [DIR ...]
+                        Collect tests from the specified directory(ies)
+                        (default [tc-tests])
+  -f FILE [FILE ...], --file FILE [FILE ...]
+                        Run tests from the specified file(s)
+  -c [CATG [CATG ...]], --category [CATG [CATG ...]]
+                        Run tests only from the specified category/ies, or if
+                        no category/ies is/are specified, list known
+                        categories.
+  -e ID [ID ...], --execute ID [ID ...]
+                        Execute the specified test cases with specified IDs
+  select action to perform on selected test cases
+  -l, --list            List all test cases, or those only within the
+                        specified category
+  -s, --show            Display the selected test cases
+  -i, --id              Generate ID numbers for new test cases
+  options for nsPlugin(run commands in net namespace)
+  -n NS, --namespace NS
+                        Run commands in namespace NS
+  options for valgrindPlugin (run command under test under Valgrind)
+  -V, --valgrind        Run commands under valgrind
+There is now a plugin architecture, and some of the functionality that
+was in the script has been moved into the plugins.
+The plugins are in the directory plugin-lib.  The are executed from
+directory plugins.  Put symbolic links from plugins to plugin-lib,
+and name them according to the order you want them to run.
+bjb@bee:~/work/tc-testing$ ls -l plugins
+total 4
+lrwxrwxrwx  1 bjb  bjb    27 Oct  4 16:12 -> 
+lrwxrwxrwx  1 bjb  bjb    25 Oct 12 17:55 -> 
+-rwxr-xr-x  1 bjb  bjb     0 Sep 29 15:56
+The plugins are a subclass of TdcPlugin, defined in and
+must be called "SubPlugin" so tdc can find them.  They are
+distinguished from each other in the python program by their module
+This base class supplies "hooks" to run extra functions.  These hooks are as 
+pre- and post-suite
+pre- and post-case
+pre- and post-execute stage
+adjust-command (runs in all stages and receives the stage name)
+The pre-suite hook receives the number of tests and an array of test ids.
+This allows you to dump out the list of skipped tests in the event of a
+failure during setup or teardown stage.
+The pre-case hook receives the ordinal number and test id of the current test.
+The adjust-command hook receives the stage id (see list below) and the
+full command to be executed.  This allows for last-minute adjustment
+of the command.
+The stages are identified by the following strings:
+  - pre  (pre-suite)
+  - setup
+  - command
+  - verify
+  - teardown
+  - post (post-suite)
+To write a plugin, you need to inherit from TdcPlugin in  To use the plugin, you have to put the
+implementation file in plugin-lib, and add a symbolic link to it from
+plugins.  It will be detected at run time and invoked at the
+appropriate times.  There are a few examples in the plugin-lib
+  -
+      implements the enforcement of running as root
+  -
+      sets up a network namespace and runs all commands in that namespace
+  -
+      runs each command in the execute stage under valgrind,
+      and checks for leaks.
+      This plugin will output an extra test for each test in the test file,
+      one is the existing output as to whether the test passed or failed,
+      and the other is a test whether the command leaked memory or not.
+      (This one is a preliminary version, it may not work quite right yet,
+      but the overall template is there and it should only need tweaks.)
diff --git a/tools/testing/selftests/tc-testing/TODO.txt 
index 6a266d811a78..c40698557e2f 100644
--- a/tools/testing/selftests/tc-testing/TODO.txt
+++ b/tools/testing/selftests/tc-testing/TODO.txt
@@ -5,6 +5,27 @@ tc Testing Suite To-Do list:
 - Add support for multiple versions of tc to run successively
-- Improve error messages when tdc aborts its run
+- Improve error messages when tdc aborts its run.  Partially done - still
+  need to better handle problems in pre- and post-suite.
-- Allow tdc to write its results to file
+- Use python logger module for debug/verbose output
+- Allow tdc to write its results to file.
+  Maybe use python logger module for this too.
+- A better implementation of the "hooks".  Currently, every plugin
+  will attempt to run a function at every hook point.  Could be
+  changed so that plugin __init__ methods will register functions to
+  be run in the various predefined times.  Then if a plugin does not
+  require action at a specific point, no penalty will be paid for
+  trying to run a function that will do nothing.
+- Proper exception handling - make an exception class and use it
+- a TestCase class, for easier testcase handling, searching, comparison
+- a TestSuite class
+  and a way to configure a test suite,
+  to automate running multiple "test suites" with different requirements
+- super simple test case example using ls, touch, etc

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