diff --git a/airflow-core/tests/unit/models/test_dag.py b/airflow-core/tests/unit/models/test_dag.py
index f9751684e35cf..6cacd239b5c68 100644
--- a/airflow-core/tests/unit/models/test_dag.py
+++ b/airflow-core/tests/unit/models/test_dag.py
@@ -1718,6 +1718,56 @@ def check_task_2(my_input):
         mock_task_object_1.assert_called()
         mock_task_object_2.assert_not_called()
 
+    @pytest.mark.parametrize(
+        ("mark_success_pattern", "expected_mapped_tasks_num"),
+        [
+            ("make_items|process_item", 1),
+            ("process_item", 3),
+        ],
+    )
+    def test_dag_test_mark_success_pattern_allows_mapped_task(
+        self,
+        mark_success_pattern,
+        expected_mapped_tasks_num,
+        testing_dag_bundle,
+    ):
+        upstream_callable = mock.MagicMock()
+        mapped_callable = mock.MagicMock()
+
+        @task_decorator
+        def make_items():
+            upstream_callable()
+            return [1, 2, 3]
+
+        with DAG(
+            dag_id="test_dag",
+            schedule=None,
+            start_date=DEFAULT_DATE,
+        ) as dag:
+            PythonOperator.partial(
+                task_id="process_item",
+                python_callable=mapped_callable,
+            ).expand(op_args=make_items())
+
+        sync_dag_to_db(dag)
+
+        dr = dag.test(mark_success_pattern=mark_success_pattern)
+
+        assert dr.state == DagRunState.SUCCESS
+
+        upstream_ti = dr.get_task_instance("make_items")
+        assert upstream_ti is not None
+        assert upstream_ti.state == TaskInstanceState.SUCCESS
+        if "make_items" in mark_success_pattern:
+            upstream_callable.assert_not_called()
+        else:
+            upstream_callable.assert_called()
+
+        mapped_tis = [ti for ti in dr.get_task_instances() if ti.task_id == "process_item"]
+        assert len(mapped_tis) == expected_mapped_tasks_num
+        assert all(ti.state == TaskInstanceState.SUCCESS for ti in mapped_tis)
+        mapped_callable.assert_not_called()
+
     def test_dag_connection_file(self, tmp_path, testing_dag_bundle):
         test_connections_string = """
 ---
diff --git a/task-sdk/src/airflow/sdk/definitions/dag.py b/task-sdk/src/airflow/sdk/definitions/dag.py
index fd47de467fea4..5f067cb4e33cf 100644
--- a/task-sdk/src/airflow/sdk/definitions/dag.py
+++ b/task-sdk/src/airflow/sdk/definitions/dag.py
@@ -1388,6 +1388,24 @@ def test(
                 executor = ExecutorLoader.get_default_executor()
                 executor.start()
 
+            def is_marked_success(ti):
+                return (
+                    re.compile(mark_success_pattern).fullmatch(ti.task_id) is not None
+                    if mark_success_pattern is not None
+                    else False
+                )
+
+            # If a mapped TI is marked successful, pre-expand it to a single mapped index
+            # without waiting for the upstream XCom value.
+            # If the upstream dependencies later run and produce an XCom during this Dag run,
+            # _revise_map_indexes_if_mapped() will update the mapped TI count to match the
+            # upstream XCom length.
+            for ti in dr.get_task_instances(session=session):
+                task = self.task_dict[ti.task_id]
+                if task.is_mapped and is_marked_success(ti):
+                    ti.map_index = 0
+            session.commit()
+
             while dr.state == DagRunState.RUNNING:
                 session.expire_all()
                 schedulable_tis, _ = dr.update_state(session=session)
@@ -1408,12 +1426,6 @@ def test(
                 for ti in scheduled_tis:
                     task = self.task_dict[ti.task_id]
 
-                    mark_success = (
-                        re.compile(mark_success_pattern).fullmatch(ti.task_id) is not None
-                        if mark_success_pattern is not None
-                        else False
-                    )
-
                     if use_executor:
                         if executor.has_task(ti):
                             continue
@@ -1440,7 +1452,7 @@ def test(
                     else:
                         # Run the task locally
                         try:
-                            if mark_success:
+                            if is_marked_success(ti):
                                 ti.set_state(TaskInstanceState.SUCCESS)
                                 log.info("[DAG TEST] Marking success for %s on %s", task, ti.logical_date)
                             else: