Initial voq chassis test cases and helpers

[tcusto]

Description of PR

Summary:
New test cases for VoQ system covering the first section of the distributed VoQ architecture test plan.

Type of change

• Bug fix
• Testbed and Framework(new/improvement)
• [ x] Test case(new/improvement)

Approach

What is the motivation for this PR?

Implement automated tests to cover "System Initialization" section of the Distributed VoQ Architecture test plan.

How did you do it?

There are new tests in test_voq_init.py for verifying the VoQ switch, system and local ports, router interfaces on local and system ports, and neighbors. The switch and port tests run on each linecard in a VoQ chassis system and verify the T2 configuration has made it correctly to the ASIC DB. The router interface test also verifies the Chassis App DB on the supervisor card. The neighbor tests verify that local neighbor creation is propagated from the local linecard to the Chassis App DB on the supervisor and into ASIC and APP DBs on remote linecards.

Inband ports are also tested in the port and router interface test, and there is a separate test case for inband neighbors establishment.

There is a voq_helpers.py containing verification and utility functions that will be shared with future VoQ test scripts. It contains routines for checking local and remote neighbors databases, checking kernel routes for remote neighbors, checking ARP tables, and other shared validations.

Lastly, in common/helpers/redis.py are classes for accessing the ASIC, APP, and Chassis APP DBs via the CLI. There are methods for getting keys from various tables and calling get or hget on keys. All of the redis db interactions that the tests perform are centralized here.

How did you verify/test it?

Ran the new tests against a chassis with T2 topology configured.

Any platform specific information?

Supported testbed topology if it's a new test case?

T2

Documentation

[lgtm-com]

This pull request introduces 2 alerts when merging 9c00e1a into 4eeda9e - view on LGTM.com

new alerts:

• 2 for Unnecessary 'else' clause in loop

[sanmalho-git]

retest vsimage please

[yxieca]

@sanmalho-git can you address the LGTM warmings?

[sanmalho-git]

@tcusto - can you address the LGTM warnings.

[shubav]

@wangxin could we merge this PR? We have new tests for how ARP & Router Interface lifecycle events work on a VoQ chassis. We can push that once this is merged, as there's a dependency. Thanks.