fix(tests): disallow empty parts Artifact

Author: punkyoon

tests/test_types.py

@@ -706,6 +706,19 @@ def test_send_message_streaming_status_update_response() -> None:
     assert isinstance(resp_err.root.error, JSONRPCError)
 
 
+def test_artifact_requires_non_empty_parts() -> None:
+    """Tests that Artifact rejects an empty parts list (min_length=1)."""
+    with pytest.raises(ValidationError, match='too_short'):
+        Artifact(artifact_id='a-1', parts=[])
+
+    # Valid: single part
+    artifact = Artifact(
+        artifact_id='a-2',
+        parts=[Part(root=TextPart(text='hello'))],
+    )
+    assert len(artifact.parts) == 1
+
+
 def test_send_message_streaming_artifact_update_response() -> None:
     text_part = TextPart(**TEXT_PART_DATA)
     data_part = DataPart(**DATA_PART_DATA)

tests/utils/test_artifact.py

@@ -3,6 +3,10 @@
 
 from unittest.mock import patch
 
+import pytest
+
+from pydantic import ValidationError
+
 from a2a.types import (
     Artifact,
     DataPart,
@@ -22,7 +26,8 @@ class TestArtifact(unittest.TestCase):
     def test_new_artifact_generates_id(self, mock_uuid4):
         mock_uuid = uuid.UUID('abcdef12-1234-5678-1234-567812345678')
         mock_uuid4.return_value = mock_uuid
-        artifact = new_artifact(parts=[], name='test_artifact')
+        parts = [Part(root=TextPart(text='test'))]
+        artifact = new_artifact(parts=parts, name='test_artifact')
         self.assertEqual(artifact.artifact_id, str(mock_uuid))
 
     def test_new_artifact_assigns_parts_name_description(self):
@@ -140,19 +145,13 @@ def test_get_artifact_text_custom_delimiter(self):
         # Verify
         assert result == 'First part | Second part | Third part'
 
-    def test_get_artifact_text_empty_parts(self):
-        # Setup
-        artifact = Artifact(
-            name='test-artifact',
-            parts=[],
-            artifact_id='test-artifact-id',
-        )
-
-        # Exercise
-        result = get_artifact_text(artifact)
-
-        # Verify
-        assert result == ''
+    def test_artifact_rejects_empty_parts(self):
+        with pytest.raises(ValidationError, match='too_short'):
+            Artifact(
+                name='test-artifact',
+                parts=[],
+                artifact_id='test-artifact-id',
+            )
 
 
 if __name__ == '__main__':