### Question:
BinaryTree { public boolean containsNode(int value) { return containsNodeRecursive(root, value); }  void add(int value); boolean isEmpty(); int getSize(); boolean containsNode(int value); void delete(int value); void traverseInOrder(Node node); void traversePreOrder(Node node); void traversePostOrder(Node node); void traverseLevelOrder();  }### Answer:
@Test public void givenABinaryTree_WhenAddingElements_ThenTreeContainsThoseElements() { BinaryTree bt = createBinaryTree(); assertTrue(bt.containsNode(6)); assertTrue(bt.containsNode(4)); assertFalse(bt.containsNode(1)); }
@Test public void givenABinaryTree_WhenLookingForNonExistingElement_ThenReturnsFalse() { BinaryTree bt = createBinaryTree(); assertFalse(bt.containsNode(99)); }