@Test
public void natural_order_tuple_value() {

  ExprValueOrdering ordering = ExprValueOrdering.natural();
  assertEquals(
      1,
      ordering.compare(
          tupleValue(ImmutableMap.of("v1", 1, "v2", 2)), tupleValue(ImmutableMap.of("v1", 3))));
  assertEquals(
      0,
      ordering.compare(
          tupleValue(ImmutableMap.of("v1", 1, "v2", 2)),
          tupleValue(ImmutableMap.of("v1", 3, "v2", 4))));
  assertEquals(
      -1,
      ordering.compare(
          tupleValue(ImmutableMap.of("v1", 3)), tupleValue(ImmutableMap.of("v1", 1, "v2", 2))));
}