public void FirstChildNextSibling_1_Constructor_1_SizeReturnsProperResult()
        {
            // Arrange
            IFirstChildNextSibling <string> tree = DSBuilder.CreateFirstChildNextSibling_Empty();
            int expected = 0;

            // Act
            int actual = tree.Size();

            Assert.AreEqual(expected, actual);
        }
        public void FirstChildNextSibling_3_BigTree_1_SizeReturnsProperResult()
        {
            // Arrange
            IFirstChildNextSibling <string> tree = DSBuilder.CreateFirstChildNextSibling_18_3();
            int expected = 11;

            // Act
            int actual = tree.Size();

            Assert.AreEqual(expected, actual);
        }