Add mgmt test for testing fabric link isolation cli commands.

[jfeng-arista]

Description of PR

Summary: Add mgmt test for testing fabric link isolation cli commands.

This change adds a test for the fabric link isolation command.
The test iterates over the fabric links on a linecard. It isolates and unisolates fabric links. Each time the state of the link is changed the state is checked in both CONFIG_DB and APPL_DB. The values in CONFIG_DB are updated by the fabric CLI commands and the values in APPL_DB are updated by the fabric manager daemon. The test check if the 2 major part work as expected.

need to wait sonic-net/sonic-buildimage#17473
Fixes # (issue)

Type of change

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

Back port request

• 201911
• 202012
• 202205
• 202305

Approach

What is the motivation for this PR?

How did you do it?

How did you verify/test it?

Any platform specific information?

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

Documentation

[jfeng-arista]

sonic-net/sonic-buildimage#17473 need to be merged first

[mssonicbld]

The pre-commit check detected issues in the files touched by this pull request.
The pre-commit check is a mandatory check, please fix detected issues.

Detailed pre-commit check results:
trim trailing whitespace.................................................Passed
fix end of files.........................................................Failed
- hook id: end-of-file-fixer
- exit code: 1
- files were modified by this hook

Fixing tests/voq/test_fabric_cli_and_db.py

check yaml...........................................(no files to check)Skipped
check for added large files..............................................Passed
check python ast.........................................................Passed
flake8...................................................................Failed
- hook id: flake8
- exit code: 1

tests/voq/test_fabric_cli_and_db.py:11:18: E221 multiple spaces before operator
tests/voq/test_fabric_cli_and_db.py:21:1: E302 expected 2 blank lines, found 1
tests/voq/test_fabric_cli_and_db.py:32:8: E111 indentation is not a multiple of 4
tests/voq/test_fabric_cli_and_db.py:33:8: E111 indentation is not a multiple of 4
tests/voq/test_fabric_cli_and_db.py:34:8: E111 indentation is not a multiple of 4
...
[truncated extra lines, please run pre-commit locally to view full check results]

To run the pre-commit checks locally, you can follow below steps:

1. Ensure that default python is python3. In sonic-mgmt docker container, default python is python2. You can run
   the check by activating the python3 virtual environment in sonic-mgmt docker container or outside of sonic-mgmt
   docker container.
2. Ensure that the pre-commit package is installed:

sudo pip install pre-commit

3. Go to repository root folder
4. Install the pre-commit hooks:

pre-commit install

5. Use pre-commit to check staged file:

pre-commit

6. Alternatively, you can check committed files using:

pre-commit run --from-ref <commit_id> --to-ref <commit_id>

[mssonicbld]

The pre-commit check detected issues in the files touched by this pull request.
The pre-commit check is a mandatory check, please fix detected issues.

Detailed pre-commit check results:
trim trailing whitespace.................................................Passed
fix end of files.........................................................Failed
- hook id: end-of-file-fixer
- exit code: 1
- files were modified by this hook

Fixing tests/voq/test_fabric_cli_and_db.py

check yaml...........................................(no files to check)Skipped
check for added large files..............................................Passed
check python ast.........................................................Passed
flake8...................................................................Failed
- hook id: flake8
- exit code: 1

tests/voq/test_fabric_cli_and_db.py:57:26: F821 undefined name 'random'
tests/voq/test_fabric_cli_and_db.py:64:13: E265 block comment should start with '# '
tests/voq/test_fabric_cli_and_db.py:66:121: E501 line too long (126 > 120 characters)
tests/voq/test_fabric_cli_and_db.py:71:19: E128 continuation line under-indented for visual indent
tests/voq/test_fabric_cli_and_db.py:79:23: E128 continuation line under-indented for visual indent
...
[truncated extra lines, please run pre-commit locally to view full check results]

To run the pre-commit checks locally, you can follow below steps:

1. Ensure that default python is python3. In sonic-mgmt docker container, default python is python2. You can run
   the check by activating the python3 virtual environment in sonic-mgmt docker container or outside of sonic-mgmt
   docker container.
2. Ensure that the pre-commit package is installed:

sudo pip install pre-commit

3. Go to repository root folder
4. Install the pre-commit hooks:

pre-commit install

5. Use pre-commit to check staged file:

pre-commit

6. Alternatively, you can check committed files using:

pre-commit run --from-ref <commit_id> --to-ref <commit_id>

[jfeng-arista]

the failures do not seem related to the change

[jfeng-arista]

/Azpw run Azure.sonic-mgmt

[mssonicbld]

/AzurePipelines run Azure.sonic-mgmt

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[jfeng-arista]

/Azpw run Azure.sonic-mgmt

[mssonicbld]

/AzurePipelines run Azure.sonic-mgmt

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[arlakshm]

@jfeng-arista please add more details in the PR description on new tests are added.

[arlakshm]

test looks good. minor comments

[jfeng-arista]

@jfeng-arista please add more details in the PR description on new tests are added.

revised. thank you !