Raise ValueError on empty DataFrame in update(), add test

Author: Saurabh Badenkal

src/PowerPlatform/Dataverse/operations/dataframe.py

@@ -242,6 +242,8 @@ def update(
         """
         if not isinstance(changes, pd.DataFrame):
             raise TypeError("changes must be a pandas DataFrame")
+        if changes.empty:
+            raise ValueError("changes must be a non-empty DataFrame")
         if id_column not in changes.columns:
             raise ValueError(f"id_column '{id_column}' not found in DataFrame columns")
 

tests/unit/test_dataframe_operations.py

@@ -290,6 +290,14 @@ def test_update_empty_change_columns(self):
             self.client.dataframe.update("account", df, id_column="accountid")
         self.assertIn("No columns to update", str(ctx.exception))
 
+    def test_update_empty_dataframe_raises(self):
+        """Empty DataFrame raises ValueError without calling the API."""
+        df = pd.DataFrame(columns=["accountid", "name"])
+        with self.assertRaises(ValueError) as ctx:
+            self.client.dataframe.update("account", df, id_column="accountid")
+        self.assertIn("non-empty", str(ctx.exception))
+        self.client._odata._update.assert_not_called()
+
     def test_update_clear_nulls_false(self):
         """NaN values are omitted from the update payload when clear_nulls=False."""
         df = pd.DataFrame([{"accountid": "guid-1", "name": "New Name", "telephone1": None}])