Handle Multi-port portchannel member case in ECMP member flap TC (sonic-net#20125)

This fixes issue mentioned in sonic-net#17887.
For pizza box DUTs, multi-port portchannel scenario was not handled, which caused issue on certain specific topologies.

How did you do it?
Add all members of PORT_CHANNEL (if the port being shutdown is part of PORT_CHANNEL) to the filtered ports list, so that during fib_test, these ports are not randomly picked as src port.

Signed-off-by: opcoder0 <110003254+opcoder0@users.noreply.github.com>

Author: deepak-singhal0408

tests/fib/test_fib.py

@@ -170,6 +170,54 @@ def filter_ports(all_port_indices, tbinfo):
     return host_ptf_ports_all
 
 
+def get_port_and_portchannel_members(port_name, all_port_indices, duts_minigraph_facts,
+                                     upstream_lc, tbinfo):
+    """
+    Get PTF port indices for a port and all its port channel members (if applicable).
+
+    Args:
+        port_name: The DUT port name to check
+        all_port_indices: Dictionary mapping PTF port indices to (asic_id, port_name)
+        duts_minigraph_facts: Minigraph facts containing port channel information
+        upstream_lc: The upstream line card hostname
+
+    Returns:
+        List of PTF port indices for the port and all its port channel members
+    """
+
+    # for T2(except UT2) topologies, no need to append, as we are already filtering out the whole upstream lc ports
+    if tbinfo['topo']['type'] == 't2' and 't2_single_node' not in tbinfo['topo']['name']:
+        return []
+
+    # Search all ASICs for port channel information
+    portchannel_members = [port_name]  # Default is just the single port
+    found_portchannel = False
+
+    for asic_id, asic_data in duts_minigraph_facts[upstream_lc]:
+        mg_facts = asic_data
+        if mg_facts and 'minigraph_portchannels' in mg_facts:
+            for pc_name, pc_info in mg_facts['minigraph_portchannels'].items():
+                if port_name in pc_info.get('members', []):
+                    portchannel_members = pc_info['members']
+                    logging.info("Port {} is a member of port channel {} with {} member(s): {}".format(
+                        port_name, pc_name, len(portchannel_members), portchannel_members))
+                    found_portchannel = True
+                    break
+        if found_portchannel:
+            break
+
+    # Find PTF port indices for all port channel members
+    ptf_ports_to_filter = []
+    for member_port in portchannel_members:
+        for ptf_port, (asic_id, dut_port) in all_port_indices.items():
+            if dut_port == member_port:
+                ptf_ports_to_filter.append(ptf_port)
+                logging.info("Found PTF port {} for port channel member {}".format(ptf_port, member_port))
+                break
+
+    return ptf_ports_to_filter
+
+
 def fib_info_files_per_function(duthosts, ptfhost, duts_running_config_facts, duts_minigraph_facts, tbinfo, request):
     """Get FIB info from database and store to text files on PTF host.
 
@@ -840,8 +888,14 @@ def test_ecmp_group_member_flap(
     logging.info("Shutting down port {}".format(nh_dut_ports[port_index_to_shut][1]))
     duthosts[0].shell("sudo config interface {} shutdown {}".format(asic_ns, nh_dut_ports[port_index_to_shut][1]))
 
-    time.sleep(10)  # Allow time for the state to stabilize
-    filtered_ports.append(nh_ptf_ports[port_index_to_shut])
+    time.sleep(60)  # Allow time for the state to stabilize
+
+    # Get all PTF ports for the port and its port channel members (if applicable)
+    ptf_ports_to_filter = get_port_and_portchannel_members(
+        nh_dut_ports[port_index_to_shut][1], all_port_indices, duts_minigraph_facts, upstream_lc, tbinfo)
+
+    # Add them to filtered_ports
+    filtered_ports.extend(ptf_ports_to_filter)
 
     # --- Re-run the PTF test after member down ---
     logging.info("Verifying ECMP behavior after member down.")
@@ -885,7 +939,11 @@ def test_ecmp_group_member_flap(
 
     logging.info("Enabling port {}".format(nh_dut_ports[port_index_to_shut][1]))
     duthosts[0].shell("sudo config interface {} startup {}".format(asic_ns, nh_dut_ports[port_index_to_shut][1]))
-    filtered_ports.pop()
+
+    # Remove the PTF ports that were added earlier
+    for ptf_port in ptf_ports_to_filter:
+        if ptf_port in filtered_ports:
+            filtered_ports.remove(ptf_port)
 
     time.sleep(60)  # Allow time for the state to stabilize