Converting legacy platform tests for a T2 chassis, adding validation of values to tests, and refactor test_sfp into smaller tests (#2965)

Summary:
The following modifications are made to some of the legacy platform tests:
- conftest.py:
    - Some of the platform tests run only on a supervisor card for a chassis.
      So, needed to change rand_one_dut_hostname to enum_dut_supervisor_hostname.
      However, in a multi-dut testbed that has no supervisor card (like DualTor),
      we would raise an exception that no supervisor card is present. Instead,
      we will now just return the first dut in the testbed.
    - Modified generate_params_supervisor_hostname function for this behavior.
- test_xcvr_info_in_db.py:
    - Use enum_rand_one_per_hwsku_frontend_hostname to run test against frontend
      node instead of rand_one_dut_hostname that could give us a supervisor card.

- test_sfp:
    - Use enum_rand_one_per_hwsku_frontend_hostname to run test against frontend
      node instead of rand_one_dut_hostname
    - Some of the new platforms don't support sfputils. So, added a check based
      on the presence of file /usr/share/sonic/device/<platform>/plugins/spfutil.py"
      If the file is not present, then we assume that sfputils is not supported.
      In this case, we don't do sfputils related steps in test_check_sfp_status_and_configure_sfp test.
      and skip test_check_sfp_low_power_mode test.

- test_show_platform.py:
    - Use enum_rand_one_per_hwsku_frontend_hostname to run tests against frontend
      node instead of rand_one_dut_hostname
    - test_show_platform_summary:
       - Added validation of fields in 'show platform summary' based on values in the inventory if defined.
          - hwsku - based on 'hwsku' variable in the inventory
          - platform - based on 'sonic_hw_platform' variable in the inventory
          - asic - based on 'asic_type' variable in the inventory
          - asic count - based on 'num_asics' variable in the inventory
    - test_show_syseeprom:
       - Validate values against 'syseeprom_info' dictionary if defined in the inventory
    - test_show_platform_psustatus:
       - Validate that atleast one of the PSU's shows status as OK.
    - test_show_platform_fan:
       - Validate that atleast one of the fans shows status as OK.


Approach
What is the motivation for this PR?
Need to run the legacy platform tests against a T2 chassis. However, some of the tests would run only on supervisor card, while others would run only on frontend nodes (linecards).

So, need to convert these tests to use the enum_* fixtures for dut selection, rather than rand_one_dut_hostname.

Also, we need to add some validation of the commands based on some variables that are defined in the inventory file - similar to the new PMON API validation.

How did you do it?
The following modifications are made to some of the legacy platform tests:

conftest.py:

Some of the platform tests run only on a supervisor card for a chassis. So, needed to change rand_one_dut_hostname to enum_dut_supervisor_hostname. However, in a multi-dut testbed that has no supervisor card (like DualTor), we would raise an exception that no supervisor card is present. Instead, we will now just return the first dut in the testbed.
Modified generate_params_supervisor_hostname function for this behavior.
test_xcvr_info_in_db.py:

Use enum_rand_one_per_hwsku_frontend_hostname to run test against frontend node instead of rand_one_dut_hostname that could give us a supervisor card.
test_sfp:

Broke into 3 smaller test for the 3 modules being tested
sfpshow
sfputil
show interface transceiver
These tests were added as a directory 'sfp' under platform_tests
In these tests:
Use enum_rand_one_per_hwsku_frontend_hostname to run test against frontend node instead of rand_one_dut_hostname
Added validation of 'sfpshow presence' and 'sfpshow eeprom'.
test_show_platform.py:

Use enum_rand_one_per_hwsku_frontend_hostname to run tests against frontend node instead of rand_one_dut_hostname
test_show_platform_summary:
Added validation of fields in 'show platform summary' based on values in the inventory if defined.
hwsku - based on 'hwsku' variable in the inventory
platform - based on 'sonic_hw_platform' variable in the inventory
asic - based on 'asic_type' variable in the inventory
asic count - based on 'num_asics' variable in the inventory
test_show_syseeprom:
Validate values against 'syseeprom_info' dictionary if defined in the inventory
test_show_platform_psustatus:
Validate that atleast one of the PSU's shows status as OK.
test_show_platform_fan:
Validate that atleast one of the fans shows status as OK.
How did you verify/test it?
Validated the modified tests against a chassis and also a pizza box.

Author: sanmalho-git

tests/conftest.py

@@ -658,8 +658,8 @@ def generate_params_supervisor_hostname(request):
         # Expecting only a single supervisor node
         if is_supervisor_node(inv_files, dut):
             return [dut]
-    pytest.fail("Test selected require a supervisor node, " +
-                "none of the DUTs '{}' in testbed '{}' are a supervisor node".format(duts, tbname))
+    # If there are no supervisor cards in a multi-dut tesbed, we are dealing with all pizza box in the testbed, pick the first DUT
+    return [duts[0]]
 
 def generate_param_asic_index(request, dut_indices, param_type):
     _, tbinfo = get_tbinfo(request)

tests/platform_tests/cli/test_show_platform.py

@@ -0,0 +1,26 @@
+import pytest
+import logging
+import os
+from tests.common.plugins.loganalyzer.loganalyzer import LogAnalyzer
+
+ans_host = None
+
+
+def teardown_module():
+    logging.info("remove script to retrieve port mapping")
+    file_path = os.path.join('/usr/share/sonic/device', ans_host.facts['platform'], 'plugins/getportmap.py')
+    ans_host.file(path=file_path, state='absent')
+
+
+@pytest.fixture(autouse=True)
+def disable_analyzer_for_mellanox(duthost):
+    if duthost.facts["asic_type"] in ["mellanox"]:
+        loganalyzer = LogAnalyzer(ansible_host=duthost, marker_prefix='sfp_cfg')
+        loganalyzer.load_common_config()
+
+        loganalyzer.ignore_regex.append("kernel.*Eeprom query failed*")
+        marker = loganalyzer.init()
+    yield
+
+    if duthost.facts["asic_type"] in ["mellanox"]:
+        loganalyzer.analyze(marker)

tests/platform_tests/sfp/__init__.py

@@ -0,0 +1,56 @@
+"""
+Check SFP status using sfpshow.
+
+This script covers test case 'Check SFP status and configure SFP' in the SONiC platform test plan:
+https://github.com/Azure/SONiC/blob/master/doc/pmon/sonic_platform_test_plan.md
+"""
+
+import logging
+import pytest
+
+from util import parse_eeprom
+from util import parse_output
+from util import get_dev_conn
+
+cmd_sfp_presence = "sudo sfpshow presence"
+cmd_sfp_eeprom = "sudo sfpshow eeprom"
+
+
+pytestmark = [
+    pytest.mark.disable_loganalyzer,  # disable automatic loganalyzer
+    pytest.mark.topology('any')
+]
+
+
+def test_check_sfp_presence(duthosts, enum_rand_one_per_hwsku_frontend_hostname, enum_frontend_asic_index, conn_graph_facts):
+    """
+    @summary: Check SFP presence using 'sfputil show presence'
+    """
+    duthost = duthosts[enum_rand_one_per_hwsku_frontend_hostname]
+    global ans_host
+    ans_host = duthost
+    portmap, dev_conn = get_dev_conn(duthost, conn_graph_facts, enum_frontend_asic_index)
+
+    logging.info("Check output of '{}'".format(cmd_sfp_presence))
+    sfp_presence = duthost.command(cmd_sfp_presence)
+    parsed_presence = parse_output(sfp_presence["stdout_lines"][2:])
+    for intf in dev_conn:
+        assert intf in parsed_presence, "Interface is not in output of '{}'".format(cmd_sfp_presence)
+        assert parsed_presence[intf] == "Present", "Interface presence is not 'Present'"
+
+
+def test_check_sfpshow_eeprom(duthosts, enum_rand_one_per_hwsku_frontend_hostname, enum_frontend_asic_index, conn_graph_facts):
+    """
+    @summary: Check SFP presence using 'sfputil show presence'
+    """
+    duthost = duthosts[enum_rand_one_per_hwsku_frontend_hostname]
+    global ans_host
+    ans_host = duthost
+    portmap, dev_conn = get_dev_conn(duthost, conn_graph_facts, enum_frontend_asic_index)
+
+    logging.info("Check output of '{}'".format(cmd_sfp_eeprom))
+    sfp_eeprom = duthost.command(cmd_sfp_eeprom)
+    parsed_eeprom = parse_eeprom(sfp_eeprom["stdout_lines"])
+    for intf in dev_conn:
+        assert intf in parsed_eeprom, "Interface is not in output of 'sfputil show eeprom'"
+        assert parsed_eeprom[intf] == "SFP EEPROM detected"