Test tweaks

.travis.yml

@@ -7,7 +7,6 @@ cache: pip
 python:
     - "3.6"
     - "3.7"
-    - "3.8-dev"
 
 install:
     - pip install -U -r requirements.txt

tests/conftest.py

@@ -43,7 +43,7 @@ app = Starlette(routes=routes)
 async def server():
     config = Config(app=app, lifespan="off")
     server = Server(config=config)
-    task = asyncio.create_task(server.serve())
+    task = asyncio.ensure_future(server.serve())
     try:
         while not server.started:
             await asyncio.sleep(0.0001)