Issue 20728: Enhance configlet/test_add_rack.py for ipv6-only topos

Currently, the test checks for both ipv4 and ipv6 neighbors
unconditionally, and will fail if either is missing. Change that
behavior to instead check to see if neighbors exist before running the
bgp checks. Add a failure case if no neighbors are found in either AF.
This way the test is AF-agnostic.

Author: anders-nexthop

tests/configlet/util/base_test.py

@@ -204,8 +204,12 @@ def apply_clet(duthost, skip_test=False):
         "DB compare failed after apply-clet"
 
     # Ensure BGP session is up
-    chk_bgp_session(duthost, tor_data["ip"]["remote"], "post-clet test")
-    chk_bgp_session(duthost, tor_data["ipv6"]["remote"].lower(), "post-clet test")
+    if len(tor_data.get("ip", []).get("remote", [])):
+        chk_bgp_session(duthost, tor_data["ip"]["remote"], "post-clet test")
+    elif len(tor_data.get("ipv6", []).get("remote", [])):
+        chk_bgp_session(duthost, tor_data["ipv6"]["remote"].lower(), "post-clet test")
+    else:
+        report_error("No neighbors detected")
 
     log_info("AddRack by template succeeded")
 
@@ -265,8 +269,12 @@ def do_test_add_rack(duthost, is_storage_backend=False, skip_load=False,
                      is_storage_backend=is_storage_backend)
 
         # Ensure BGP session is up before we apply stripped minigraph
-        chk_bgp_session(duthost, tor_data["ip"]["remote"], "pre-clet test")
-        chk_bgp_session(duthost, tor_data["ipv6"]["remote"].lower(), "pre-clet test")
+        if len(tor_data.get("ip", []).get("remote", [])):
+            chk_bgp_session(duthost, tor_data["ip"]["remote"], "pre-clet test")
+        elif len(tor_data.get("ipv6", []).get("remote", [])):
+            chk_bgp_session(duthost, tor_data["ipv6"]["remote"].lower(), "pre-clet test")
+        else:
+            report_error("No neighbors detected")
 
         set_log_prefix_msg("test prepare")
         prepare_for_test(duthost)

tests/configlet/util/generic_patch.py

@@ -171,8 +171,12 @@ def generic_patch_add_t0(duthost, skip_load=False, hack_apply=False):
         "DB compare failed after adding T0 via generic patch updater"
 
     # Ensure BGP session is up
-    chk_bgp_session(duthost, tor_data["ip"]["remote"], "post-patch-add test")
-    chk_bgp_session(duthost, tor_data["ipv6"]["remote"].lower(), "post-patch-add test")
+    if len(tor_data.get("ip", []).get("remote", [])):
+        chk_bgp_session(duthost, tor_data["ip"]["remote"], "post-patch-add test")
+    elif len(tor_data.get("ipv6", []).get("remote", [])):
+        chk_bgp_session(duthost, tor_data["ipv6"]["remote"].lower(), "post-patch-add test")
+    else:
+        report_error("No neighbors detected")
 
 
 def generic_patch_rm_t0(duthost, skip_load=False, hack_apply=False):