Added ping test for bgp neighbors ~TestGap 02/2025 (sonic-net#17266)

What is the motivation for this PR?
Currently, sonic-mgmt didn't have ping test for bgp neighbors.

How did you do it?
Adding a new Testcase to bgp testsuite to verify ping.

How did you verify/test it?
Ran in Microsoft Lab on T0 and T2 chassis both manually and on Elastic test as well

Co-authored-by: yatishkoul <yatishkoul@gmail.com>

Author: YatishSVC

tests/bgp/test_ping_bgp_neighbor.py

@@ -0,0 +1,40 @@
+import pytest
+import logging
+
+pytestmark = [
+    pytest.mark.topology('any')
+]
+
+
+def test_ping_bgp_neighbor(duthosts, enum_frontend_dut_hostname, enum_asic_index):
+    """Check ping connectivity to all BGP neighbors across all ASICs of the given DUT"""
+
+    duthost = duthosts[enum_frontend_dut_hostname]
+    if enum_asic_index is None:
+        pytest.skip(f"Skipping test since {duthost.hostname} is not a multi-ASIC device.")
+
+    bgp_facts = duthost.bgp_facts(instance_id=enum_asic_index)['ansible_facts']
+    namespace = duthost.get_namespace_from_asic_id(enum_asic_index)
+    asic_info = f"(namespace: {namespace})" if namespace else ""
+
+    for neighbor_ip, neighbor_data in bgp_facts['bgp_neighbors'].items():
+        # Verify that the BGP session is established
+        error_msg = f"BGP session with {neighbor_ip} is not 'established'"
+        assert neighbor_data['state'] == 'established', error_msg
+        logging.info(f"Pinging BGP neighbor {neighbor_ip} from {duthost.hostname} {asic_info}")
+        if namespace:
+            ping_cmd = f"sudo ip netns exec {namespace} ping -c 1 {neighbor_ip}"
+        else:
+            ping_cmd = f"ping -c 1 {neighbor_ip}"
+
+        result = duthost.shell(ping_cmd, module_ignore_errors=True)
+        # Checking if the ping was successful
+        if result['rc'] != 0:
+            logging.error(f"Ping failed to BGP neighbor {neighbor_ip} from {duthost.hostname} {asic_info}")
+            raise AssertionError(
+                f"Ping failed to BGP neighbor {neighbor_ip} from {duthost.hostname} "
+                f"{asic_info}"
+            )
+        logging.info(f"Ping to BGP neighbor {neighbor_ip} successful from {duthost.hostname} {asic_info}")
+
+    logging.info(f"All BGP neighbors on {duthost.hostname} {asic_info} are reachable via ping.")