TST: xfail non-nano json test

Author: jbrockmendel

pandas/tests/io/json/test_pandas.py

@@ -1793,8 +1793,11 @@ def test_read_json_with_very_long_file_path(self, compression):
     @pytest.mark.parametrize(
         "date_format,key", [("epoch", 86400000), ("iso", "P1DT0H0M0S")]
     )
-    def test_timedelta_as_label(self, date_format, key):
-        df = DataFrame([[1]], columns=[pd.Timedelta("1D")])
+    def test_timedelta_as_label(self, date_format, key, unit, request):
+        if unit != "ns":
+            mark = pytest.mark.xfail(reason="GH#63236 failure to round-trip")
+            request.applymarker(mark)
+        df = DataFrame([[1]], columns=[pd.Timedelta("1D").as_unit(unit)])
         expected = f'{{"{key}":{{"0":1}}}}'
 
         expected_warning = None