to [cqw, cqh].
      assert_unit_equals(child, '10cqw', '30px');
      assert_unit_equals(child, '10cqi', '30px');
      assert_unit_equals(child, '10cqh', '40px');
      assert_unit_equals(child, '10cqb', '40px');

      child.className = 'vertical';
      // [cqi, cqb] now corresponds to [cqh, cqw].
      assert_unit_equals(child, '10cqw', '30px');
      assert_unit_equals(child, '10cqi', '40px');
      assert_unit_equals(child, '10cqh', '40px');
      assert_unit_equals(child, '10cqb', '30px');

      c2