fixup test_iloc

Author: MarcoGorelli

pandas/tests/indexing/test_iloc.py

@@ -723,7 +723,10 @@ def test_iloc_setitem_with_scalar_index(self, indexer, value):
         # elementwisely, not using "setter('A', ['Z'])".
 
         df = DataFrame([[1, 2], [3, 4]], columns=["A", "B"])
-        df.iloc[0, indexer] = value
+        with tm.assert_produces_warning(
+            FutureWarning, match="item of incompatible dtype"
+        ):
+            df.iloc[0, indexer] = value
         result = df.iloc[0, 0]
 
         assert is_scalar(result) and result == "Z"