[Auto-Techsupport] Fix the coredump_gen_handler Exception when the History table is empty (sonic-net#2265)

coredump_gen_handler script is throwing exception currently when the history table is empty.
Fix this issue and add a UT

Signed-off-by: Vivek Reddy Karri <[email protected]>

Author: vivekrnv

tests/coredump_gen_handler_test.py

@@ -449,3 +449,23 @@ def mock_cmd(cmd, env):
             patcher.fs.create_file("/var/core/orchagent.12345.123.core.gz")
             cls = cdump_mod.CriticalProcCoreDumpHandle("orchagent.12345.123.core.gz", "swss", redis_mock)
             cls.handle_core_dump_creation_event()
+
+    def test_auto_ts_empty_state_db(self):
+        """
+        Scenario: Check if the techsupport is called as expected even when the history table in empty
+                  and container cooloff is non-zero
+        """
+        db_wrap = Db()
+        redis_mock = db_wrap.db
+        set_auto_ts_cfg(redis_mock, state="enabled", since_cfg="2 days ago")
+        set_feature_table_cfg(redis_mock, state="enabled", rate_limit_interval="300")
+        with Patcher() as patcher:
+            def mock_cmd(cmd, env):
+                cmd_str = " ".join(cmd)
+                if "show techsupport" in cmd_str and cmd_str != TS_DEFAULT_CMD:
+                    assert False, "Expected TS_CMD: {}, Recieved: {}".format(TS_DEFAULT_CMD, cmd_str)
+                return 0, AUTO_TS_STDOUT, ""
+            ts_helper.subprocess_exec = mock_cmd
+            patcher.fs.create_file("/var/core/orchagent.12345.123.core.gz")
+            cls = cdump_mod.CriticalProcCoreDumpHandle("orchagent.12345.123.core.gz", "swss", redis_mock)
+            cls.handle_core_dump_creation_event()

utilities_common/auto_techsupport_helper.py

@@ -259,7 +259,7 @@ def get_ts_map(db):
     ts_map = {}
     ts_keys = db.keys(STATE_DB, TS_MAP+"*")
     if not ts_keys:
-        return
+        return ts_map
     for ts_key in ts_keys:
         data = db.get_all(STATE_DB, ts_key)
         if not data: