Fix AttributeError when notifier renders templates with SerializedDAG

task-sdk/src/airflow/sdk/definitions/_internal/templater.py

@@ -76,7 +76,7 @@ def get_template_env(self, dag: DAG | None = None) -> jinja2.Environment:
         # for most of the functionalities. It is imported by get_template_env()
         # though, so we don't need to put this after the 'if dag' check.
 
-        if dag:
+        if dag and hasattr(dag, "get_template_env"):
             return dag.get_template_env(force_sandboxed=False)
         return SandboxedEnvironment(cache_size=0)
 

task-sdk/tests/task_sdk/bases/test_notifier.py

@@ -97,3 +97,23 @@ def test_notifier_call_with_prepared_context(self, caplog):
             }
         )
         assert notifier.message == "task: some_task"
+
+    def test_render_template_fields_with_serialized_dag(self):
+        """Rendering template fields with a SerializedDAG-like object should not raise AttributeError.
+
+        When `airflow dags test` runs callbacks, the context contains a SerializedDAG which does
+        not have a `get_template_env` method. The notifier must fall back to a SandboxedEnvironment
+        rather than raising AttributeError.
+        """
+
+        class FakeSerializedDAG:
+            """Simulate SerializedDAG which lacks get_template_env."""
+
+            dag_id = "test_dag"
+            render_template_as_native_obj = False
+
+        notifier = MockNotifier(message="Hello {{ dag.dag_id }}")
+        context: Context = {"dag": FakeSerializedDAG()}
+        # Must not raise AttributeError: 'FakeSerializedDAG' object has no attribute 'get_template_env'
+        notifier.render_template_fields(context)
+        assert notifier.message == "Hello test_dag"