public void TestIsDescendant()
        {
            // ACTION
            var isDescendant    = _grandpa.IsDescendent(_me);
            var isNotDescendant = _dad.IsDescendent(_cousin);

            // ASSERT
            Assert.True(isDescendant);
            Assert.False(isNotDescendant);
        }
        public void TestMakeChildOfUpperSibling()
        {
            // ACTION
            _me.MakeChildOfUpperSibling(); // Right-arrow functionality
            var isChildOfSisterNow = _sister.IsDescendent(_me);
            var isParentOfMeNow    = _me.Parent == _sister;

            // ASSERT
            Assert.True(isChildOfSisterNow);
            Assert.True(isParentOfMeNow);
        }