add unit tests and make flake8 happy

sanic/app.py

@@ -641,7 +641,10 @@ class Sanic:
             has_log=log_config is not None)
 
         # Trigger before_start events
-        await self.trigger_events(server_settings.get('before_start', []), server_settings.get('loop'))
+        await self.trigger_events(
+            server_settings.get('before_start', []),
+            server_settings.get('loop')
+        )
 
         return await serve(**server_settings)
 

tests/test_server_events.py

@@ -59,3 +59,20 @@ def test_all_listeners():
     start_stop_app(random_name_app)
     for listener_name in AVAILABLE_LISTENERS:
         assert random_name_app.name + listener_name == output.pop()
+
+
+async def test_trigger_before_events_create_server():
+
+    class MySanicDb:
+        pass
+
+    app = Sanic("test_sanic_app")
+
+    @app.listener('before_server_start')
+    async def init_db(app, loop):
+        app.db = MySanicDb()
+
+    await app.create_server()
+
+    assert hasattr(app, "db")
+    assert isinstance(app.db, MySanicDb)

tox.ini

@@ -10,6 +10,7 @@ deps =
     coverage
     pytest
     pytest-cov
+    pytest-sanic
     pytest-sugar
     aiohttp==1.3.5
     chardet<=2.3.0