Added queue challenge.

stacks_queues/queue_list/test_queue_list.py

@@ -0,0 +1,36 @@
+from nose.tools import assert_equal
+
+
+class TestQueue(object):
+    
+    # TODO: It would be better if we had unit tests for each
+    # method in addition to the following end-to-end test
+    def test_end_to_end(self):
+        print('Test: Dequeue an empty queue')
+        queue = Queue()
+        assert_equal(queue.dequeue(), None)
+
+        print('Test: Enqueue to an empty queue')
+        queue.enqueue(1)
+
+        print('Test: Dequeue a queue with one element')
+        assert_equal(queue.dequeue(), 1)
+
+        print('Test: Enqueue to a non-empty queue')
+        queue.enqueue(2)
+        queue.enqueue(3)
+        queue.enqueue(4)
+
+        print('Test: Dequeue a queue with more than one element')
+        assert_equal(queue.dequeue(), 2)
+        assert_equal(queue.dequeue(), 3)
+        assert_equal(queue.dequeue(), 4)
+        
+        print('Success: test_end_to_end')
+
+def main():
+    test = TestQueue()
+    test.test_end_to_end()
+    
+if __name__ == '__main__':
+    main()