Better async testing.

test/completion/async_.py

@@ -2,14 +2,16 @@
 Tests for all async use cases.
 
 Currently we're not supporting completion of them, but they should at least not
-raise errors or return strange results.
+raise errors or return extremely strange results.
 """
 
-
 async def x():
-    await 3
+    argh = await x()
+    #? 
+    argh
+    return 2
 
-#?
+#? int()
 x()
 
 a = await x()
@@ -17,3 +19,7 @@ a = await x()
 a
 
 
+async def x2():
+    async with open('asdf') as f:
+        #? ['readlines']
+        f.readlines