public void Clear_NonEmptyTree_Tree_ShouldBe_Empty()
{
var myIntegerTree = new NaryTree <int>();
//test to see if the tree is empty
var isEmpty = myIntegerTree.IsEmpty();
Assert.IsTrue(isEmpty);
var added = myIntegerTree.InsertTopLevel(9);
//should return true that it was added
Assert.IsTrue(added);
myIntegerTree.Clear();
Assert.IsTrue(myIntegerTree.IsEmpty());
}