diff --git a/api/tests/unit_tests/core/workflow/nodes/llm/test_node.py b/api/tests/unit_tests/core/workflow/nodes/llm/test_node.py
index 78433ccb9d..daa3ae35a9 100644
--- a/api/tests/unit_tests/core/workflow/nodes/llm/test_node.py
+++ b/api/tests/unit_tests/core/workflow/nodes/llm/test_node.py
@@ -631,3 +631,88 @@ class TestExtractContentTypeAndExtension:
             content_type, extension = _extract_content_type_and_extension("https://example.com/image", content_type)
             assert content_type == "application/octet-stream"
             assert extension == ".bin"
+
+
+class TestSaveMultimodalOutputAndConvertResultToMarkdown:
+    def test_str_content(self, llm_node_for_multimodal):
+        llm_node, mock_file_downloader, mock_file_saver = llm_node_for_multimodal
+        gen = llm_node._save_multimodal_output_and_convert_result_to_markdown("hello world")
+        assert list(gen) == ["hello world"]
+        mock_file_downloader.get.assert_not_called()
+        mock_file_saver.save_file.assert_not_called()
+
+    def test_text_prompt_message_content(self, llm_node_for_multimodal):
+        llm_node, mock_file_downloader, mock_file_saver = llm_node_for_multimodal
+        gen = llm_node._save_multimodal_output_and_convert_result_to_markdown(
+            [TextPromptMessageContent(data="hello world")]
+        )
+        assert list(gen) == ["hello world"]
+        mock_file_downloader.get.assert_not_called()
+        mock_file_saver.save_file.assert_not_called()
+
+    def test_image_content(self, llm_node_for_multimodal):
+        llm_node, mock_file_downloader, mock_file_saver = llm_node_for_multimodal
+
+        image_raw_data = b"PNG_DATA"
+        image_b64_data = base64.b64encode(image_raw_data).decode()
+
+        mock_saved_file = File(
+            id=str(uuid.uuid4()),
+            tenant_id="1",
+            type=FileType.IMAGE,
+            transfer_method=FileTransferMethod.TOOL_FILE,
+            filename="test.png",
+            extension=".png",
+            size=len(image_raw_data),
+            related_id=str(uuid.uuid4()),
+            url="https://example.com/test.png",
+            storage_key="test_storage_key",
+        )
+        mock_file_saver.save_file.return_value = mock_saved_file
+        gen = llm_node._save_multimodal_output_and_convert_result_to_markdown(
+            [
+                ImagePromptMessageContent(
+                    format="png",
+                    base64_data=image_b64_data,
+                    mime_type="image/png",
+                )
+            ]
+        )
+        yielded_strs = list(gen)
+        assert len(yielded_strs) == 1
+        # This assertion is somewhat tricky.
+        expected_file_url = f"http://127.0.0.1:5001/files/tools/{mock_saved_file.related_id}.png"
+        assert yielded_strs[0].startswith(f"![]({expected_file_url}")
+        assert yielded_strs[0].endswith(")")
+        mock_file_saver.save_file.assert_called_once_with(
+            MultiModalFile(
+                user_id="1",
+                tenant_id="1",
+                file_type=FileType.IMAGE,
+                data=image_raw_data,
+                mime_type="image/png",
+            )
+        )
+        mock_file_downloader.assert_not_called()
+        assert mock_saved_file in llm_node._file_outputs
+
+    def test_unknown_content_type(self, llm_node_for_multimodal):
+        llm_node, mock_file_downloader, mock_file_saver = llm_node_for_multimodal
+        gen = llm_node._save_multimodal_output_and_convert_result_to_markdown(frozenset(["hello world"]))
+        assert list(gen) == ["frozenset({'hello world'})"]
+        mock_file_downloader.get.assert_not_called()
+        mock_file_saver.save_file.assert_not_called()
+
+    def test_unknown_item_type(self, llm_node_for_multimodal):
+        llm_node, mock_file_downloader, mock_file_saver = llm_node_for_multimodal
+        gen = llm_node._save_multimodal_output_and_convert_result_to_markdown([frozenset(["hello world"])])
+        assert list(gen) == ["frozenset({'hello world'})"]
+        mock_file_downloader.get.assert_not_called()
+        mock_file_saver.save_file.assert_not_called()
+
+    def test_none_content(self, llm_node_for_multimodal):
+        llm_node, mock_file_downloader, mock_file_saver = llm_node_for_multimodal
+        gen = llm_node._save_multimodal_output_and_convert_result_to_markdown(None)
+        assert list(gen) == []
+        mock_file_downloader.get.assert_not_called()
+        mock_file_saver.save_file.assert_not_called()