Fix fixture invocation order in qos/qos_sai_base.py

[vivekverma-arista]

Description of PR

Summary: Fix fixture invocation order in qos/qos_sai_base.py Fixes # (issue)

Type of change

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

Back port request

• [ ] 201911
• [ ] 202012
• [ ] 202205
• [ ] 202305
• [x] 202311

Approach

What is the motivation for this PR?

qos/test_qos_sai.py fail with the following -

failed on setup with "Failed: Not all critical processes are healthy"

The fixture dut_disable_ipv6 disables ipv6 due to which the following critical processes don't come up after swapping syncd ( fixture swapSyncd_on_selected_duts ) -

1. program:snmpd
2. program:snmp-subagent

And this issue only hits if swapSyncd_on_selected_duts is executed after dut_disable_ipv6 and since there is no dependency between these fixtures, they can execute in any order.

How did you do it?

This change introduces a dependency between dut_disable_ipv6 & swapSyncd_on_selected_duts such that former is always executed after latter.

How did you verify/test it?

Tested on Arista-7050CX3 platform with dualtor topology.

Any platform specific information?

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

Documentation

[StormLiangMS]

hi @neethajohn @XuChen-MSFT could you help to review?

[neethajohn]

@XuChen-MSFT , please take a look

[StormLiangMS]

hi @vivekverma-arista could you run test with 202311 image?

[vivekverma-arista]

hi @vivekverma-arista could you run test with 202311 image?

Hi @StormLiangMS I have tested with 202311 image. The test passes and no new regression is seen because of this fix.

[mssonicbld]

Cherry-pick PR to 202311: https://github.com/sonic-net/sonic-mgmt/pull/12596