feat: add convert_document_to_annotate_file_json (#124)

* feat: add convert_document_to_annotate_file_json

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

---------

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

google/cloud/documentai_toolbox/wrappers/document.py

@@ -732,6 +732,19 @@ def convert_document_to_annotate_file_response(self) -> AnnotateFileResponse:
         """
         return _convert_to_vision_annotate_file_response(self.text, self.pages)
 
+    def convert_document_to_annotate_file_json_response(self) -> str:
+        r"""Convert OCR data from Document.proto to JSON str of AnnotateFileResponse for Vision API.
+
+        Args:
+            None.
+        Returns:
+            str:
+                JSON string of TextAnnotations.
+        """
+        return AnnotateFileResponse.to_json(
+            _convert_to_vision_annotate_file_response(self.text, self.pages)
+        )
+
     def export_images(
         self, output_path: str, output_file_prefix: str, output_file_extension: str
     ) -> List[str]:

tests/unit/test_document.py

@@ -536,6 +536,19 @@ def test_convert_document_to_annotate_file_response():
     assert actual == expected
 
 
+def test_convert_document_to_annotate_file_json_response():
+    doc = document.Document.from_document_path(
+        document_path="tests/unit/resources/0/toolbox_invoice_test-0.json"
+    )
+
+    actual = doc.convert_document_to_annotate_file_json_response()
+
+    with open("tests/unit/resources/toolbox_invoice_test-0-vision.json", "r") as f:
+        expected = f.read()
+
+    assert actual == expected
+
+
 def test_export_images(get_bytes_images_mock):
     doc = document.Document.from_gcs(
         gcs_bucket_name="test-directory", gcs_prefix="documentai/output/123456789/0"