fix not using_infer_string build

Author: jbrockmendel

pandas/tests/extension/test_string.py

@@ -265,6 +265,14 @@ def test_loc_setitem_with_expansion_preserves_ea_index_dtype(
             request.applymarker(mark)
         super().test_loc_setitem_with_expansion_preserves_ea_index_dtype(data)
 
+    def test_loc_setitem_with_expansion_retains_ea_dtype(
+        self, data, using_infer_string, request
+    ):
+        if not using_infer_string and data.dtype.storage == "python":
+            mark = pytest.mark.xfail(reason="Gives object")
+            request.applymarker(mark)
+        super().test_loc_setitem_with_expansion_retains_ea_dtype(data)
+
 
 class Test2DCompat(base.Dim2CompatTests):
     @pytest.fixture(autouse=True)

pandas/tests/series/indexing/test_setitem.py

@@ -601,8 +601,10 @@ def test_setitem_enlargement_object_none(self, nulls_fixture, using_infer_string
         tm.assert_series_equal(ser, expected)
         if dtype == "str":
             ser[3] is np.nan
-        else:
+        elif using_infer_string:
             assert ser[3] is nulls_fixture
+        else:
+            assert type(ser[3]) is type(nulls_fixture)
 
 
 def test_setitem_scalar_into_readonly_backing_data():