Add more unit test to cover debug executor (apache#35400)

scripts/cov/core_coverage.py

@@ -35,7 +35,6 @@
 
 files_not_fully_covered = [
     # executors
-    "airflow/executors/debug_executor.py",
     "airflow/executors/executor_loader.py",
     "airflow/executors/local_executor.py",
     "airflow/executors/sequential_executor.py",

tests/executors/test_debug_executor.py

@@ -124,3 +124,27 @@ def test_is_single_threaded(self):
 
     def test_is_production_default_value(self):
         assert not DebugExecutor.is_production
+
+    @mock.patch("time.sleep", autospec=True)
+    def test_trigger_sleep_when_no_task(self, mock_sleep):
+        execute_mock = MagicMock()
+        executor = DebugExecutor()
+        executor.execute_async = execute_mock
+        executor.queued_tasks = {}
+        executor.trigger_tasks(open_slots=5)
+        mock_sleep.assert_called()
+
+    @mock.patch("airflow.executors.debug_executor.DebugExecutor.change_state")
+    def test_sync_after_terminate(self, change_state_mock):
+        executor = DebugExecutor()
+
+        ti1 = MagicMock(key="t1")
+        executor.tasks_to_run = [ti1]
+        executor.terminate()
+        executor.sync()
+
+        change_state_mock.assert_has_calls(
+            [
+                mock.call(ti1.key, State.FAILED),
+            ]
+        )