Description of PR

Summary:
Fixes # (issue)

Type of change

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

Approach

What is the motivation for this PR?

When dealing with SONiC Chassis you have cards of different type

• linecards with front-panel ports
• supervisor card
• fabric cards

Also, you could have linecards with different hwsku's in the same chassis.

When using the parameterized approach for multi-dut to select test cases to run on a chassis, we need to make sure that we parameterize the tests to provide all the required coverage.

How did you do it?

Added the following fixtures that can be used for parameterizing tests for chassis:

• rand_one_frontend_dut_hostname - returns a random dut that is a frontend node.
• enum_supervisor_dut_hostname - returns a dut that is a supervisor node. For pizza box (single dut) this will the pizza box itself.
  • A supervisor node is defined as having 'type' variable in the inventory as 'supervisor'
  • For pizza box (single dut) the single dut itself will be the supervisor node.
• enum_frontend_dut_hostname - returns all duts that are frontend nodes
  • A frontend node is defined as a node that is not a supervisor.
• enum_rand_one_per_hwsku_frontend_hostname - returns 1 random frontend dut per hwsksu amongst all the frontend nodes.
  - hwsku for a node is derived from the 'hwsku' or 'sonic_hwsku' variable in the inventory for the node.

To achieve the above:

• Added dut_utils under common/helpers to:

  • get_inventory_variable - get the value of a variable in the inventory for a given node.
  • is_supervisor_node - check if 'type' variable is defined in the inventory for the node and is 'supervisor'
  • is_frontend_node - check if node is not a supervisor node.

• Modified SonicHost.is_supervisor_node to use dut_utils.is_supervisor_node.

How did you verify/test it?

Created a sample test case to exercise the selection of DUT's in a multi-dut testbed.

import logging

def test_one_frontend_node(rand_one_frontend_dut_hostname,):
    logging.info("Running test against " + rand_one_frontend_dut_hostname)

def test_all_frontend_nodes(enum_frontend_dut_hostname):
    logging.info("Running test against " + enum_frontend_dut_hostname)

def test_superivisor(enum_supervisor_dut_hostname):
    logging.info("Running test against " + enum_supervisor_dut_hostname)

def test_all_nodes(enum_dut_hostname):
    logging.info("Running test against " + enum_dut_hostname)

def test_one_node(rand_one_dut_hostname):
    logging.info("Running test against " + rand_one_dut_hostname)

def test_one_per_hwsku(enum_rand_one_per_hwsku_frontend_hostname):
    logging.info("Running test against " + enum_rand_one_per_hwsku_frontend_hostname)

The test were run against a Chassis testbed with the following cads:

• board1 - frontend node (linecard) with hwsku1
• board2 - frontend node (linecard) with hwsku1
• board3 - frontend node (linecard) with hwsku2
• board4 - supervisor node

The pytest results of running the sample test above against the testbed above is shown below.

=========================== short test summary info ============================
PASSED ../tests/sample_test.py::test_one_frontend_node
      21:46:20 INFO sample_test.py:test_one_frontend_node:5: Running test against board1

PASSED ../tests/sample_test.py::test_all_frontend_nodes[board1]
PASSED ../tests/sample_test.py::test_all_frontend_nodes[board2]
PASSED ../tests/sample_test.py::test_all_frontend_nodes[board3]

PASSED ../tests/sample_test.py::test_superivisor[board4]

PASSED ../tests/sample_test.py::test_all_nodes[board1]
PASSED ../tests/sample_test.py::test_all_nodes[board2]
PASSED ../tests/sample_test.py::test_all_nodes[board3]
PASSED ../tests/sample_test.py::test_all_nodes[board4]

PASSED ../tests/sample_test.py::test_one_node
      21:46:39 INFO sample_test.py:test_one_node:21: Running test against board4

PASSED ../tests/sample_test.py::test_one_per_hwsku[board1]
PASSED ../tests/sample_test.py::test_one_per_hwsku[board3]

========================== 12 passed in 82.67 seconds ==========================

Any platform specific information?

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

Documentation