[test gap] Add two test cases to cover lldp neighbors or interfaces incomplete scenarios by ZhaohuiS · Pull Request #22420 · sonic-net/sonic-mgmt

ZhaohuiS · 2026-02-14T07:28:41Z

Description of PR

Summary:
Fixes # (issue)
Address #22376

Type of change

Back port request

Approach

What is the motivation for this PR?

To add 2 new test cases to check if all lldp neighbors exist and if all interfaces exists in lldpcli show interfaces.
We don't have a test case to cover the issue we found in PR: sonic-net/sonic-buildimage#25436

#22562 cover some scenarios, but not all of them. So I removed the test case in #22562 and add 2 test cases with more checks in this PR.

How did you do it?

1. test_lldp_interfaces

Purpose: Verify LLDP functionality across all interfaces without config reload

Key Features:

Validates LLDP table completeness
Verifies lldpcli interface discovery
Checks lldpctl_facts consistency
Validates chassis ID and capabilities
Active syslog monitoring via loganalyzer

Test Steps:

Recording Phase: Capture all interfaces from show interface status
LLDP Table Verification: Compare LLDP table with interface status (admin up, no PortChannels)
lldpcli Verification: Compare lldpcli output with interface status (all interfaces, no PortChannels)
lldpctl_facts Verification: Compare lldpctl_facts with interface status (admin up, no PortChannels)
Consistency Check: Verify all lldpctl_facts interfaces exist in lldpcli
Chassis Verification: Validate chassis MAC address and capabilities (Bridge: on, Router: on, Wlan: off, Station: off)

2. test_lldp_interface_config_reload

Purpose: Verify LLDP functionality persists correctly after config reload

Key Features:

Tests LLDP recovery after config reload
Validates interface persistence
Ensures neighbor rediscovery
Monitors for LLDP-specific errors while ignoring expected reload errors
Addresses the core issue from GitHub [test gap] check lldp neighbors after config reload #22376

Test Steps:

Pre-Reload Recording: Capture all interfaces before config reload
Config Reload: Perform safe config reload with interface checks
Stabilization Wait: Wait for critical services and LLDP convergence
LLDP Table Verification: Compare LLDP table with pre-reload interfaces (admin up, no PortChannels)
lldpcli Verification: Compare lldpcli output with pre-reload interfaces (all interfaces, no PortChannels)
lldpctl_facts Verification: Compare lldpctl_facts with pre-reload interfaces (admin up, no PortChannels)
Consistency Check: Verify all lldpctl_facts interfaces exist in lldpcli
Chassis Verification: Validate chassis MAC and capabilities remain correct

How did you verify/test it?

run it on testbed.

Any platform specific information?

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

Documentation

mssonicbld · 2026-02-14T07:28:50Z

/azp run

azure-pipelines · 2026-02-14T07:29:05Z

Azure Pipelines successfully started running 1 pipeline(s).

…ncompete scenarios Signed-off-by: Zhaohui Sun <zhaohuisun@microsoft.com>

Signed-off-by: Zhaohui Sun <zhaohuisun@microsoft.com>

mssonicbld · 2026-03-03T12:19:17Z

/azp run

azure-pipelines · 2026-03-03T12:19:31Z

Azure Pipelines successfully started running 1 pipeline(s).

Copilot

Pull request overview

This PR updates the LLDP test suite in sonic-mgmt to close a test gap for scenarios where LLDP interface/neighbor discovery is incomplete (notably after config reload), aligning coverage with the failure mode described in issue #22376.

Changes:

Replaces the prior test_lldp_after_config_reload with two new tests: one validating LLDP interface/chassis correctness without reload and one validating persistence after config reload.
Adds reusable helper functions to validate show lldp table, lldpcli show interfaces, lldpctl_facts, and chassis output consistency.
Adds syslog checking via loganalyzer match/ignore patterns for LLDP-specific errors.

tests/lldp/test_lldp.py

mssonicbld · 2026-03-13T02:56:10Z

/azp run

azure-pipelines · 2026-03-13T02:56:25Z

Azure Pipelines successfully started running 1 pipeline(s).

- Replace 'if loganalyzer else None' with 'contextlib.nullcontext()' to avoid crash when loganalyzer is disabled (None is not a context manager) - Use DEVICE_METADATA['localhost']['mac'] for T2 topology chassis-id instead of always using mgmt interface MAC, consistent with existing check_lldp_neighbor() logic Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Signed-off-by: Zhaohui Sun <zhaohuisun@microsoft.com>

mssonicbld · 2026-03-13T03:01:35Z

/azp run

azure-pipelines · 2026-03-13T03:01:49Z

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mssonicbld · 2026-03-17T07:55:02Z

/azp run

azure-pipelines · 2026-03-17T07:55:15Z

Azure Pipelines successfully started running 1 pipeline(s).

On dualtor testbeds, some admin-up interfaces may not have LLDP neighbors, causing false assertion failures. Change strict equality check to only fail when LLDP/lldpctl table has unexpected extra interfaces that are not admin-up or are PortChannels. Signed-off-by: Zhaohui Sun <zhaohuisun@microsoft.com>

mssonicbld · 2026-03-17T08:24:06Z

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azure-pipelines · 2026-03-17T08:24:21Z

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…-reload baseline - Override match_regex for ALL DUTs (not just selected one) to only match LLDP-specific errors, since fixture teardown analyzes all DUTs - Remove per-DUT ignore_regex for config reload (no longer needed with the override approach) - Use pre-reload LLDP neighbor count as baseline for post-reload wait instead of computing expected count from interface status - Improve error message in verify_lldp_table for clarity Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Signed-off-by: Zhaohui Sun <zhaohuisun@microsoft.com>

mssonicbld · 2026-03-18T07:22:10Z

/azp run

azure-pipelines · 2026-03-18T07:22:24Z

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On KVM testbeds (asic_type='vs'), eth0 is a virtual management interface with no LLDP neighbor on the other end, so it won't appear in LLDP table, lldpcli interfaces, or lldpctl_facts. Make the eth0 assertions conditional: - Physical testbeds: assert eth0 must be present (unchanged behavior) - Virtual testbeds: log info message instead of failing Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Signed-off-by: Zhaohui Sun <zhaohuisun@microsoft.com>

mssonicbld · 2026-03-19T02:01:04Z

/azp run

azure-pipelines · 2026-03-19T02:01:19Z

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SonicAsic has 'asic_index' as a property, not 'get_asic_index()' method. This caused AttributeError on T2 multi-ASIC testbeds. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Signed-off-by: Zhaohui Sun <zhaohuisun@microsoft.com>

mssonicbld · 2026-03-19T07:57:37Z

/azp run

azure-pipelines · 2026-03-19T07:57:51Z

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On multi-ASIC systems, 'docker exec lldp{N} lldpcli show interfaces' only returns interfaces for ASIC N, but 'show interface status' returns all interfaces across all ASICs. Filter intf_status_output to only include ports belonging to the current ASIC before comparing with lldpcli output. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Signed-off-by: Zhaohui Sun <zhaohuisun@microsoft.com>

mssonicbld · 2026-03-19T09:59:29Z

/azp run

azure-pipelines · 2026-03-19T09:59:44Z

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On multi-ASIC T2, each ASIC's lldp container reports its own ASIC-level MAC from DEVICE_METADATA, not the global device MAC. Use asic.config_facts() instead of duthost.config_facts() to get the correct expected chassis MAC for multi-ASIC systems. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Signed-off-by: Zhaohui Sun <zhaohuisun@microsoft.com>

mssonicbld · 2026-03-19T13:37:02Z

/azp run

azure-pipelines · 2026-03-19T13:37:20Z

Azure Pipelines successfully started running 1 pipeline(s).

ZhaohuiS · 2026-03-23T02:03:46Z

@StormLiangMS @yxieca could you please help review?

StormLiangMS

Overall: Good quality — a few suggestions

The refactoring from a monolithic test into 4 reusable helpers (verify_lldp_table, verify_lldpcli_interfaces, verify_lldpctl_facts, verify_chassis_info) is well done. Multi-ASIC, virtual/KVM, and loganalyzer handling all look solid. KVM CI passed cleanly.

Feedback:

LLDP table parsing (verify_lldp_table): Parsing show lldp table by splitting on whitespace is fragile — if a neighbor name contains spaces, parts[0] won't be the interface. Consider using duthost.show_and_parse("show lldp table") for more robust parsing, consistent with how intf_status_output is obtained.
Duplicated chassis MAC logic: The chassis MAC computation block (T2 multi-ASIC vs single-ASIC vs non-T2) is duplicated in both test_lldp_interfaces and test_lldp_interfaces_config_reload. Consider extracting it into a helper like get_expected_chassis_mac(duthost, asic, tbinfo) to reduce duplication.
Hardcoded capability assertions: The test asserts Wlan: off, Station: off for all platforms. Are there any SONiC deployments where these would differ? If so, consider making these configurable or conditional.

1. Use show_and_parse for LLDP table parsing instead of fragile whitespace splitting (verify_lldp_table) 2. Extract chassis MAC logic into get_expected_chassis_mac() helper to eliminate duplication between test_lldp_interfaces and test_lldp_interfaces_config_reload 3. Make Wlan/Station capability checks conditional - only assert 'off' if the capability is reported (not all platforms list them) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Signed-off-by: Zhaohui Sun <zhaohuisun@microsoft.com>

mssonicbld · 2026-03-23T02:46:26Z

/azp run

azure-pipelines · 2026-03-23T02:46:40Z

Azure Pipelines successfully started running 1 pipeline(s).

…nd_parse show_and_parse('show lldp table') may include separator lines ('-----') and footer lines ('Total entries...') as parsed entries. Filter these out by checking the localport value. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Signed-off-by: Zhaohui Sun <zhaohuisun@microsoft.com>

mssonicbld · 2026-03-23T03:26:36Z

/azp run

azure-pipelines · 2026-03-23T03:26:48Z

Azure Pipelines successfully started running 1 pipeline(s).

ZhaohuiS · 2026-03-23T04:26:52Z

Thanks @StormLiangMS for the thorough review! All 3 suggestions have been addressed in commit 802efe6:

LLDP table parsing — Switched to show_and_parse("show lldp table") for robust parsing (also added filtering for separator/footer lines that show_and_parse may include).
Chassis MAC helper — Extracted into get_expected_chassis_mac(duthost, asic, tbinfo) to eliminate duplication.
Wlan/Station capabilities — Now conditional: only assert off if the capability is reported by the platform.

Verified all 5 tests pass on T1 physical testbed (testbed-bjw2-can-t1-7260-12, Arista 7260CX3).

StormLiangMS

LGTM

…ncomplete scenarios (sonic-net#22420) What is the motivation for this PR? To add 2 new test cases to check if all lldp neighbors exist and if all interfaces exists in lldpcli show interfaces. We don't have a test case to cover the issue we found in PR: sonic-net/sonic-buildimage#25436 sonic-net#22562 cover some scenarios, but not all of them. So I removed the test case in sonic-net#22562 and add 2 test cases with more checks in this PR. How did you do it? 1. test_lldp_interfaces Purpose: Verify LLDP functionality across all interfaces without config reload Key Features: Validates LLDP table completeness Verifies lldpcli interface discovery Checks lldpctl_facts consistency Validates chassis ID and capabilities Active syslog monitoring via loganalyzer Test Steps: Recording Phase: Capture all interfaces from show interface status LLDP Table Verification: Compare LLDP table with interface status (admin up, no PortChannels) lldpcli Verification: Compare lldpcli output with interface status (all interfaces, no PortChannels) lldpctl_facts Verification: Compare lldpctl_facts with interface status (admin up, no PortChannels) Consistency Check: Verify all lldpctl_facts interfaces exist in lldpcli Chassis Verification: Validate chassis MAC address and capabilities (Bridge: on, Router: on, Wlan: off, Station: off) 2. test_lldp_interface_config_reload Purpose: Verify LLDP functionality persists correctly after config reload Key Features: Tests LLDP recovery after config reload Validates interface persistence Ensures neighbor rediscovery Monitors for LLDP-specific errors while ignoring expected reload errors Addresses the core issue from GitHub [test gap] check lldp neighbors after config reload sonic-net#22376 Test Steps: Pre-Reload Recording: Capture all interfaces before config reload Config Reload: Perform safe config reload with interface checks Stabilization Wait: Wait for critical services and LLDP convergence LLDP Table Verification: Compare LLDP table with pre-reload interfaces (admin up, no PortChannels) lldpcli Verification: Compare lldpcli output with pre-reload interfaces (all interfaces, no PortChannels) lldpctl_facts Verification: Compare lldpctl_facts with pre-reload interfaces (admin up, no PortChannels) Consistency Check: Verify all lldpctl_facts interfaces exist in lldpcli Chassis Verification: Validate chassis MAC and capabilities remain correct How did you verify/test it? run it on testbed. Signed-off-by: Zhaohui Sun <zhaohuisun@microsoft.com> Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Signed-off-by: Venkata Gouri Rajesh Etla <vrajeshe@cisco.com>

…ncomplete scenarios (sonic-net#22420) What is the motivation for this PR? To add 2 new test cases to check if all lldp neighbors exist and if all interfaces exists in lldpcli show interfaces. We don't have a test case to cover the issue we found in PR: sonic-net/sonic-buildimage#25436 sonic-net#22562 cover some scenarios, but not all of them. So I removed the test case in sonic-net#22562 and add 2 test cases with more checks in this PR. How did you do it? 1. test_lldp_interfaces Purpose: Verify LLDP functionality across all interfaces without config reload Key Features: Validates LLDP table completeness Verifies lldpcli interface discovery Checks lldpctl_facts consistency Validates chassis ID and capabilities Active syslog monitoring via loganalyzer Test Steps: Recording Phase: Capture all interfaces from show interface status LLDP Table Verification: Compare LLDP table with interface status (admin up, no PortChannels) lldpcli Verification: Compare lldpcli output with interface status (all interfaces, no PortChannels) lldpctl_facts Verification: Compare lldpctl_facts with interface status (admin up, no PortChannels) Consistency Check: Verify all lldpctl_facts interfaces exist in lldpcli Chassis Verification: Validate chassis MAC address and capabilities (Bridge: on, Router: on, Wlan: off, Station: off) 2. test_lldp_interface_config_reload Purpose: Verify LLDP functionality persists correctly after config reload Key Features: Tests LLDP recovery after config reload Validates interface persistence Ensures neighbor rediscovery Monitors for LLDP-specific errors while ignoring expected reload errors Addresses the core issue from GitHub [test gap] check lldp neighbors after config reload sonic-net#22376 Test Steps: Pre-Reload Recording: Capture all interfaces before config reload Config Reload: Perform safe config reload with interface checks Stabilization Wait: Wait for critical services and LLDP convergence LLDP Table Verification: Compare LLDP table with pre-reload interfaces (admin up, no PortChannels) lldpcli Verification: Compare lldpcli output with pre-reload interfaces (all interfaces, no PortChannels) lldpctl_facts Verification: Compare lldpctl_facts with pre-reload interfaces (admin up, no PortChannels) Consistency Check: Verify all lldpctl_facts interfaces exist in lldpcli Chassis Verification: Validate chassis MAC and capabilities remain correct How did you verify/test it? run it on testbed. Signed-off-by: Zhaohui Sun <zhaohuisun@microsoft.com> Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

rustiqly mentioned this pull request Feb 24, 2026

[lldp] Add test_lldp_after_config_reload to verify LLDP recovery #22449

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ZhaohuiS added 2 commits March 3, 2026 12:12

[test gap] Add two test cases to cover lldp neighbors or interfaces i…

b15afd3

…ncompete scenarios Signed-off-by: Zhaohui Sun <zhaohuisun@microsoft.com>

add some functions to make it easy to read

b8102e8

Signed-off-by: Zhaohui Sun <zhaohuisun@microsoft.com>

ZhaohuiS force-pushed the Zhaohui/lldp_interface_test_gap branch from 082f763 to b8102e8 Compare March 3, 2026 12:19

ZhaohuiS requested review from StormLiangMS, Copilot and yxieca March 4, 2026 05:23

Copilot started reviewing on behalf of ZhaohuiS March 4, 2026 05:23 View session

Copilot AI reviewed Mar 4, 2026

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ZhaohuiS force-pushed the Zhaohui/lldp_interface_test_gap branch from 32643f0 to b11d285 Compare March 13, 2026 03:01

ZhaohuiS force-pushed the Zhaohui/lldp_interface_test_gap branch from 87295e2 to b6397d5 Compare March 17, 2026 08:23

StormLiangMS reviewed Mar 23, 2026

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StormLiangMS approved these changes Mar 23, 2026

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StormLiangMS merged commit 6f38722 into sonic-net:master Mar 23, 2026
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Description of PR

Type of change

Back port request

Approach

What is the motivation for this PR?

How did you do it?

1. test_lldp_interfaces

2. test_lldp_interface_config_reload

How did you verify/test it?

Any platform specific information?

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

Documentation

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Pull request overview

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