Use async syntax on aiohttp_utils

tests/integration/aiohttp_utils.py

@@ -1,22 +1,14 @@
-import asyncio
-
 import aiohttp
 
 
-@asyncio.coroutine
-def aiohttp_request(loop, method, url, output='text', encoding='utf-8', **kwargs):
-    session = aiohttp.ClientSession(loop=loop)
-    response_ctx = session.request(method, url, **kwargs)  # NOQA: E999
-
-    response = yield from response_ctx.__aenter__()  # NOQA: E999
-    if output == 'text':
-        content = yield from response.text()  # NOQA: E999
-    elif output == 'json':
-        content = yield from response.json(encoding=encoding)  # NOQA: E999
-    elif output == 'raw':
-        content = yield from response.read()  # NOQA: E999
-
-    response_ctx._resp.close()
-    yield from session.close()
+async def aiohttp_request(loop, method, url, output='text', encoding='utf-8', **kwargs):  # NOQA: E999
+    async with aiohttp.ClientSession(loop=loop) as session:  # NOQA: E999
+        async with session.request(method, url, **kwargs) as response:  # NOQA: E999
+            if output == 'text':
+                content = await response.text()  # NOQA: E999
+            elif output == 'json':
+                content = await response.json(encoding=encoding)  # NOQA: E999
+            elif output == 'raw':
+                content = await response.read()  # NOQA: E999
 
-    return response, content
+            return response, content