Fix show ip route json and show ipv6 route json when there is no IPv4 or IPv6 route (#4177) (#4363)

* remove early return



* add unit tests for IP4 only and IP6 only scenarios



* fix incorrect UT data format



* fix UT data



* add early return for non-json case



---------

Signed-off-by: BYGX-wcr <wcr@live.cn>
Signed-off-by: Priyansh Tratiya <ptratiya@microsoft.com>
Co-authored-by: Changrong Wu <wcr@live.cn>

Author: thisptr-sh

show/bgp_common.py

@@ -415,10 +415,10 @@ def show_routes(args, namespace, display, verbose, ipver):
         else:
             combined_route = route_info
 
-    if not combined_route:
-        return
-
     if not found_json:
+        if len(combined_route) == 0:
+            return
+
         #print out the header if this is not a json request
         if not filter_by_ip:
             print_show_ip_route_hdr()

tests/route_check_test_data.py

@@ -1704,4 +1704,63 @@
         },
         RET: -1,
     },
+    "33": {
+        DESCR: "Good test case, only IPv4 routes",
+        MULTI_ASIC: False,
+        NAMESPACE: [''],
+        ARGS: "route_check -m INFO -i 1000",
+        PRE: {
+            DEFAULTNS: {
+                APPL_DB: {
+                    ROUTE_TABLE: {
+                        "0.0.0.0/0": {"ifname": "portchannel0"},
+                        "10.10.196.12/31": {"ifname": "portchannel0"},
+                        "10.10.196.20/31": {"ifname": "portchannel0"},
+                        "10.10.196.30/31": {"ifname": "lo"}
+                    },
+                    INTF_TABLE: {
+                        "PortChannel1013:10.10.196.24/31": {},
+                        "PortChannel1024": {}
+                    }
+                },
+                ASIC_DB: {
+                    RT_ENTRY_TABLE: {
+                        ASIC_RT_ENTRY_KEY_PREFIX + "10.10.196.12/31" + ASIC_RT_ENTRY_KEY_SUFFIX: {},
+                        ASIC_RT_ENTRY_KEY_PREFIX + "10.10.196.20/31" + ASIC_RT_ENTRY_KEY_SUFFIX: {},
+                        ASIC_RT_ENTRY_KEY_PREFIX + "10.10.196.24/32" + ASIC_RT_ENTRY_KEY_SUFFIX: {},
+                        ASIC_RT_ENTRY_KEY_PREFIX + "0.0.0.0/0" + ASIC_RT_ENTRY_KEY_SUFFIX: {}
+                    }
+                }
+            }
+        }
+    },
+    "34": {
+        DESCR: "Good test case, only IPv6 routes",
+        MULTI_ASIC: False,
+        NAMESPACE: [''],
+        ARGS: "route_check -m INFO -i 1000",
+        PRE: {
+            DEFAULTNS: {
+                APPL_DB: {
+                    ROUTE_TABLE: {
+                        "::/0": {"ifname": "portchannel0"},
+                        "2603:10b0:503:df4::6c/126": {"ifname": "portchannel0"},
+                        "2603:10b0:503:df4::7c/126": {"ifname": "portchannel0"},
+                    },
+                    INTF_TABLE: {
+                        "PortChannel1023:2603:10b0:503:df4::5d/126": {},
+                        "PortChannel1024": {}
+                    }
+                },
+                ASIC_DB: {
+                    RT_ENTRY_TABLE: {
+                        ASIC_RT_ENTRY_KEY_PREFIX + "2603:10b0:503:df4::5d/128" + ASIC_RT_ENTRY_KEY_SUFFIX: {},
+                        ASIC_RT_ENTRY_KEY_PREFIX + "2603:10b0:503:df4::6c/126" + ASIC_RT_ENTRY_KEY_SUFFIX: {},
+                        ASIC_RT_ENTRY_KEY_PREFIX + "2603:10b0:503:df4::7c/126" + ASIC_RT_ENTRY_KEY_SUFFIX: {},
+                        ASIC_RT_ENTRY_KEY_PREFIX + "::/0" + ASIC_RT_ENTRY_KEY_SUFFIX: {}
+                    }
+                }
+            }
+        }
+    },
 }