Add dualtor standby drop test and check dhcpmon count based on number…

… of dhcp servers configured (sonic-net#9088)

tests/dhcp_relay/test_dhcp_relay.py

@@ -220,6 +220,9 @@ def testing_config(request, duthosts, rand_one_dut_hostname, tbinfo):
         if testing_mode == DUAL_TOR_MODE:
             pytest.skip("skip DUAL_TOR_MODE tests on t0-56-vlan2po testbeds")
     else:
+        if testing_mode == DUAL_TOR_MODE:
+            pytest.skip("skip DUAL_TOR_MODE tests on Single ToR testbeds")
+
         if testing_mode == SINGLE_TOR_MODE:
             if subtype_exist:
                 duthost.shell('redis-cli -n 4 HDEL "DEVICE_METADATA|localhost" "subtype"')
@@ -287,31 +290,43 @@ def start_dhcp_monitor_debug_counter(duthost):
 
 
 def test_dhcp_relay_default(ptfhost, dut_dhcp_relay_data, validate_dut_routes_exist, testing_config,
-                            toggle_all_simulator_ports_to_rand_selected_tor_m):     # noqa F811
+                            rand_unselected_dut, toggle_all_simulator_ports_to_rand_selected_tor_m):     # noqa F811
     """Test DHCP relay functionality on T0 topology.
        For each DHCP relay agent running on the DuT, verify DHCP packets are relayed properly
     """
+
     testing_mode, duthost, testbed_mode = testing_config
 
     if testing_mode == DUAL_TOR_MODE:
         skip_release(duthost, ["201811", "201911"])
 
-    skip_dhcpmon = (testing_mode == DUAL_TOR_MODE or
-                    any(vers in duthost.os_version for vers in ["201811", "201911", "202111"]))
+    skip_dhcpmon = any(vers in duthost.os_version for vers in ["201811", "201911", "202111"])
 
     try:
         for dhcp_relay in dut_dhcp_relay_data:
             if not skip_dhcpmon:
+                dhcp_server_num = len(dhcp_relay['downlink_vlan_iface']['dhcp_server_addrs'])
+                if testing_mode == DUAL_TOR_MODE:
+                    standby_duthost = rand_unselected_dut
+                    start_dhcp_monitor_debug_counter(standby_duthost)
+                    expected_standby_agg_counter_message = (
+                        r".*dhcp_relay#dhcpmon\[[0-9]+\]: "
+                        r"\[\s*Agg-%s\s*-[\sA-Za-z0-9]+\s*rx/tx\] "
+                        r"Discover: +0/ +0, Offer: +0/ +0, Request: +0/ +0, ACK: +0/ +0+"
+                    ) % (dhcp_relay['downlink_vlan_iface']['name'])
+                    loganalyzer_standby = LogAnalyzer(ansible_host=standby_duthost, marker_prefix="dhcpmon counter")
+                    marker_standby = loganalyzer_standby.init()
+                    loganalyzer_standby.expect_regex = [expected_standby_agg_counter_message]
                 start_dhcp_monitor_debug_counter(duthost)
                 expected_agg_counter_message = (
                     r".*dhcp_relay#dhcpmon\[[0-9]+\]: "
                     r"\[\s*Agg-%s\s*-[\sA-Za-z0-9]+\s*rx/tx\] "
-                    r"Discover: +1/ +4, Offer: +1/ +1, Request: +3/ +12, ACK: +1/ +1+"
-                ) % dhcp_relay['downlink_vlan_iface']['name']
+                    r"Discover: +1/ +%d, Offer: +1/ +1, Request: +3/ +%d, ACK: +1/ +1+"
+                ) % (dhcp_relay['downlink_vlan_iface']['name'], dhcp_server_num, dhcp_server_num * 3)
                 loganalyzer = LogAnalyzer(ansible_host=duthost, marker_prefix="dhcpmon counter")
-                loganalyzer.expect_regex = []
                 marker = loganalyzer.init()
                 loganalyzer.expect_regex = [expected_agg_counter_message]
+
             # Run the DHCP relay test on the PTF host
             ptf_runner(ptfhost,
                        "ptftests",
@@ -339,13 +354,19 @@ def test_dhcp_relay_default(ptfhost, dut_dhcp_relay_data, validate_dut_routes_ex
             if not skip_dhcpmon:
                 time.sleep(18)      # dhcpmon debug counter prints every 18 seconds
                 loganalyzer.analyze(marker)
+                if testing_mode == DUAL_TOR_MODE:
+                    loganalyzer_standby.analyze(marker_standby)
     except LogAnalyzerError as err:
         logger.error("Unable to find expected log in syslog")
         raise err
 
-    # Clean up - Restart DHCP relay service on DUT to recover original dhcpmon setting
-    restart_dhcp_service(duthost)
-    pytest_assert(wait_until(120, 5, 0, check_interface_status, duthost))
+    if not skip_dhcpmon:
+        # Clean up - Restart DHCP relay service on DUT to recover original dhcpmon setting
+        restart_dhcp_service(duthost)
+        if testing_mode == DUAL_TOR_MODE:
+            restart_dhcp_service(standby_duthost)
+            pytest_assert(wait_until(120, 5, 0, check_interface_status, standby_duthost))
+        pytest_assert(wait_until(120, 5, 0, check_interface_status, duthost))
 
 
 def test_dhcp_relay_after_link_flap(ptfhost, dut_dhcp_relay_data, validate_dut_routes_exist, testing_config):