ADD test for update_documents_ndjson

Author: Azanul

tests/index/test_index_document_meilisearch.py

@@ -193,3 +193,13 @@ def test_add_documents_ndjson(empty_index, songs_ndjson):
     task = index.wait_for_task(response.task_uid)
     assert task.status == 'succeeded'
     assert index.get_primary_key() == 'id'
+
+def test_update_documents_ndjson(index_with_documents, songs_ndjson):
+    """Tests updating a single document with ndjson string."""
+    index = index_with_documents()
+    response = index.update_documents_ndjson(songs_ndjson)
+    assert isinstance(response, TaskInfo)
+    assert response.task_uid != None
+    task = index.wait_for_task(response.task_uid)
+    assert task.status == 'succeeded'
+    assert index.get_primary_key() == 'id'