fix(abstractions): allow empty part values and relax adapter requirement in MultipartBody

packages/abstractions/kiota_abstractions/multipart_body.py

@@ -58,7 +58,7 @@
             raise ValueError("Part name cannot be null")
         if not content_type:
             raise ValueError("Content type cannot be null")
-        if not part_value:
+        if part_value is None:
             raise ValueError("Part value cannot be null")
         value: tuple[str, Any, Optional[str]] = (content_type, part_value, filename)
         self.parts[self._normalize_part_name(part_name)] = value
@@ -92,7 +92,7 @@
         """
         raise NotImplementedError()
 
     def serialize(self, writer: SerializationWriter) -> None:
         """Writes the objects properties to the current writer.
 
         Args:
@@ -100,10 +100,14 @@
         """
         if not writer:
             raise ValueError("Serialization writer cannot be null")
-        if not self.request_adapter or not self.request_adapter.get_serialization_writer_factory():
-            raise ValueError("Request adapter or serialization writer factory cannot be null")
         if not self.parts:
             raise ValueError("No parts to serialize")
+        if any(isinstance(part[1], Parsable) for part in self.parts.values()):
+            if (
+                not self.request_adapter
+                or not self.request_adapter.get_serialization_writer_factory()
+            ):
+                raise ValueError("Request adapter or serialization writer factory cannot be null")
 
         first = True
         for part_name, part_value in self.parts.items():
@@ -115,7 +119,7 @@
             writer.write_str_value("", f"--{self.boundary}")
             writer.write_str_value("Content-Type", f"{part_value[0]}")
             writer.write_str_value(
-                "Content-Disposition", self._get_comtent_disposition(part_name, part_value)
+                "Content-Disposition", self._get_content_disposition(part_name, part_value)
             )
             self._add_new_line(writer)
 
@@ -139,13 +143,15 @@
     def _add_new_line(self, writer: SerializationWriter) -> None:
         writer.write_str_value("", "")
 
-    def _get_comtent_disposition(
+    def _get_content_disposition(
         self, part_name: str, part_value: tuple[str, Any, Optional[str]]
     ) -> str:
         if len(part_value) >= 3 and part_value[2] is not None:
             return f'form-data; name="{part_name}"; filename="{part_value[2]}"'
         return f'form-data; name="{part_name}"'
 
+    _get_comtent_disposition = _get_content_disposition
+
     def _write_parsable(
         self, writer: SerializationWriter, part_value: tuple[str, Any, Optional[str]]
     ) -> None:

packages/abstractions/tests/test_multipart_body.py

@@ -1,8 +1,13 @@
+import io
+from unittest.mock import Mock
+
 import pytest
 
 from kiota_abstractions.multipart_body import MultipartBody
 from kiota_abstractions.serialization import SerializationWriter
 
+from .conftest import MockEntity
+
 
 def test_defensive():
     """Tests initialization of MultipartBody objects
@@ -32,7 +37,8 @@ def test_defensive():
     with pytest.raises(ValueError) as excinfo:
         multipart.serialize(None)
     assert "Serialization writer cannot be null" in str(excinfo.value)
-
+
+
 def test_add_or_replace_part():
     """Tests adding or replacing a part in the multipart body
     """
@@ -42,6 +48,7 @@ def test_add_or_replace_part():
     multipart.add_or_replace_part("text", "text/plain", "Hello, World! 2")
     assert multipart.get_part_value("text") == "Hello, World! 2"
 
+
 def test_remove_part():
     """Tests removing a part from the multipart body
     """
@@ -50,4 +57,52 @@ def test_remove_part():
     assert multipart.get_part_value("text") == "Hello, World!"
     assert multipart.remove_part("text")
     assert not multipart.get_part_value("text")
-    assert not multipart.remove_part("text")
+    assert not multipart.remove_part("text")
+
+
+def test_add_or_replace_part_empty_values():
+    """Tests adding empty byte and string parts to the multipart body."""
+    multipart = MultipartBody()
+    multipart.add_or_replace_part("empty_bytes", "application/octet-stream", b"")
+    assert multipart.get_part_value("empty_bytes") == b""
+
+    multipart.add_or_replace_part("empty_str", "text/plain", "")
+    assert multipart.get_part_value("empty_str") == ""
+
+
+def test_content_disposition():
+    multipart = MultipartBody()
+    disp_with_file = multipart._get_content_disposition(
+        "doc", ("application/pdf", b"data", "doc.pdf")
+    )
+    assert disp_with_file == 'form-data; name="doc"; filename="doc.pdf"'
+
+    disp_without_file = multipart._get_content_disposition("text", ("text/plain", "hello", None))
+    assert disp_without_file == 'form-data; name="text"'
+
+    # Verify backward-compatible alias
+    assert multipart._get_comtent_disposition(
+        "doc", ("application/pdf", b"data", "doc.pdf")
+    ) == disp_with_file
+
+
+def test_serialize_without_request_adapter():
+    multipart = MultipartBody()
+    multipart.add_or_replace_part("text", "text/plain", "Hello")
+    multipart.add_or_replace_part("binary", "application/octet-stream", b"123")
+    multipart.add_or_replace_part("stream", "application/octet-stream", io.BytesIO(b"456"))
+
+    mock_writer = Mock(spec=SerializationWriter)
+    multipart.serialize(mock_writer)
+    assert mock_writer.write_str_value.called
+    assert mock_writer.write_bytes_value.called
+
+
+def test_serialize_parsable_requires_request_adapter():
+    multipart = MultipartBody()
+    multipart.add_or_replace_part("entity", "application/json", MockEntity())
+
+    mock_writer = Mock(spec=SerializationWriter)
+    with pytest.raises(ValueError) as excinfo:
+        multipart.serialize(mock_writer)
+    assert "Request adapter or serialization writer factory cannot be null" in str(excinfo.value)