Add unit test for handling fabric switch_id.

tests/dvslib/dvs_database.py

@@ -109,7 +109,19 @@ def delete_field(self, table_name: str, key: str, field: str) -> None:
         """
         table = swsscommon.Table(self.db_connection, table_name)
         table.hdel(key, field)
-
+
+    def set_field(self, table_name: str, key: str, field: str, value: str) -> None:
+        """Add/Update a field in an entry stored at `key` in the specified table.
+
+        Args:
+            table_name: The name of the table where the entry is being removed.
+            key: The key that maps to the entry being added/updated.
+            field: The field that needs to be added/updated.
+            value: The value that is set for the field.
+        """
+        table = swsscommon.Table(self.db_connection, table_name)
+        table.hset(key, field, value)
+
     def get_keys(self, table_name: str) -> List[str]:
         """Get all of the keys stored in the specified table.
 

tests/test_fabric_switch_id.py

@@ -0,0 +1,47 @@
+from dvslib.dvs_common import wait_for_result, PollingConfig
+import pytest
+
+class TestFabricSwitchId(object):
+    def check_syslog(self, dvs, marker, log, expected_cnt=1):
+        def do_check_syslog():
+            (ec, out) = dvs.runcmd(['sh', '-c', "awk \'/%s/,ENDFILE {print;}\' /var/log/syslog | grep \'%s\' | wc -l" %(marker, log)])
+            return (out.strip() == str(expected_cnt), None)
+        max_poll = PollingConfig(polling_interval=5, timeout=600, strict=True)
+        wait_for_result(do_check_syslog, polling_config=max_poll)
+
+    def test_invalid_fabric_switch_id(self, vst):
+        # Find supervisor dvs.
+        dvs = None
+        config_db = None
+        for name in vst.dvss.keys():
+            dvs = dvss[name]
+            config_db = dvs.get_config_db()
+            metatbl = config_db.get_entry("DEVICE_METADATA", "localhost")
+            cfg_switch_type = metatbl.get("switch_type")
+            if cfg_switch_type == "fabric":
+                break
+        assert dvs and config_db
+
+        # Verify orchagent's handling of invalid fabric switch_id in following cases:
+        # - Invalid fabric switch_id, e.g, -1, is set.
+        # - fabric switch_id is missing in ConfigDb.
+        for invalid_switch_id in (-1, None):
+            if invalid_switch_id is None:
+                config_db.delete_field("DEVICE_METADATA", "localhost", "switch_id")
+                expected_log = "Fabric switch id is not configured"
+            else:
+                config_db.set_field("DEVICE_METADATA", "localhost", "switch_id", str( invalid_switch_id))
+                expected_log = f"Invalid fabric switch id {invalid_switch_id} configured"
+
+            # Restart orchagent and verify orchagent behavior by checking syslog.
+            dvs.stop_swss()
+            marker = dvs.add_log_marker()
+            dvs.start_swss()
+            self.check_syslog(dvs, marker , expected_log)
+
+
+# Add Dummy always-pass test at end as workaroud
+# for issue when Flaky fail on final test it invokes module tear-down before retrying
+def test_nonflaky_dummy():
+    pass
+