don't forget to await for switch to close

tests/pubsub/testfloodsub.nim

@@ -7,7 +7,7 @@
 ## This file may not be copied, modified, or distributed except according to
 ## those terms.
 
-import unittest, sequtils, options
+import unittest, sequtils
 import chronos
 import utils,
        ../../libp2p/[switch,

tests/testswitch.nim

@@ -101,6 +101,7 @@ suite "Switch":
 
       check isNil(conn)
       discard allFutures(switch1.stop(), switch2.stop())
+      await allFutures(awaiters)
       result = true
 
     check: