Reuse app fixture in tests

tests/test_multiprocessing.py

@@ -2,15 +2,13 @@ import multiprocessing
 import random
 import signal
 
-from sanic import Sanic
 from sanic.testing import HOST, PORT
 
 
-def test_multiprocessing():
+def test_multiprocessing(app):
     """Tests that the number of children we produce is correct"""
     # Selects a number at random so we can spot check
     num_workers = random.choice(range(2,  multiprocessing.cpu_count() * 2 + 1))
-    app = Sanic('test_multiprocessing')
     process_list = set()
 
     def stop_on_alarm(*args):