t.Errorf("unmarshaling of %s failed: %s", &tx, err)
				continue
			}
			if rx.Cmp(&tx) != 0 {
				t.Errorf("JSON encoding of %s failed: got %s want %s", &tx, &rx, &tx)
			}
		}
	}
}

func TestIntJSONEncodingNil(t *testing.T) {
	var x *Int
	b, err := x.MarshalJSON()
	if err != nil {
		t.Fatalf("marshaling of nil failed: %s", err)
	}
	got := string(b)
	want := "null"
	if got != want {