RED - test constructor.
GREEN - constructor throws NullPointerException
REFACTOR - Cleaned up some code.
RED - created test for constructQueue()
GREEN - constructQueue now returns a queue.
REFACTOR - created a string with file path
RED - test if elements are added to the queue
GREEN - elements are added to the queue
REFACTOR - Added @Before method in MainTest
RED - mock test for queue.getSize() inside Tree class
GREEN - getSize() is called in a loop
REFACTOR - clean up
RED - test if tree is null
GREEN - Tree returned is not null
REFACTOR - clean up code