tdc - Linux Traffic Control (tc) unit testing suite

Author: Lucas Bates - lucasb@mojatatu.com

tdc is a Python script to load tc unit tests from a separate JSON file and
execute them inside a network namespace dedicated to the task.


REQUIREMENTS
------------

*  Minimum Python version of 3.4. Earlier 3.X versions may work but are not
   guaranteed.

*  The kernel must have network namespace support

*   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:
   ./tdc.py -c

   Note:
   In the current release, tdc run will abort due to a failure in setup or
   teardown commands - which includes not being able to run a test simply
   because the kernel did not support a specific feature. (This will be
   handled in a future version - the current workaround is to run the tests
   on specific test categories that your kernel supports)


BEFORE YOU RUN
--------------

The path to the tc executable that will be most commonly tested can be defined
in the tdc_config.py file. Find the 'TC' entry in the NAMES dictionary and
define the path.

If you need to test a different tc executable on the fly, you can do so by
using the -p option when running tdc:
	./tdc.py -p /path/to/tc


RUNNING TDC
-----------

To use tdc, root privileges are required. tdc will not run otherwise.

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:
	./tdc.py -h

tdc will list the test names as they are being run, and print a summary in
TAP (Test Anything Protocol) format when they are done. If tests fail,
output captured from the failing test will be printed immediately following
the failed test in the TAP output.


USER-DEFINED CONSTANTS
----------------------

The tdc_config.py file contains multiple values that can be altered to suit
your needs. Any value in the NAMES dictionary can be altered without affecting
the tests to be run. These values are used in the tc commands that will be
executed as part of the test. More will be added as test cases require.

Example:
	$TC qdisc add dev $DEV1 ingress


COMMAND LINE ARGUMENTS
----------------------

Run tdc.py -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


ACKNOWLEDGEMENTS
----------------

Thanks to:

Jamal Hadi Salim, for providing valuable test cases
Keara Leibovitz, who wrote the CLI test driver that I used as a base for the
   first version of the tc testing suite. This work was presented at
   Netdev 1.2 Tokyo in October 2016.
Samir Hussain, for providing help while I dove into Python for the first time
    and being a second eye for this code.