restructure wait_closed to make sure it sends the chan closed...

wsfwd/__init__.py

@@ -163,6 +163,12 @@ class WFStreamWriter:
 
 		return self._closed
 
+	async def _close_task(self):
+		await self._client._sendcmd(dict(cmd='chanclose', chan=self._stream))
+
+		self._closed_event.set()
+		self._closed_event = None
+
 	def close(self):
 		'''
 		https://docs.python.org/3/library/asyncio-stream.html#asyncio.StreamWriter.close
@@ -170,20 +176,18 @@ class WFStreamWriter:
 
 		self._closed = True
 
-		self._closed_event.set()
-		self._closed_event = None
-
-		self._closetask = asyncio.create_task(self._client._sendcmd(dict(cmd='chanclose', chan=self._stream)))
+		self._closetask = asyncio.create_task(self._close_task())
 
 	async def wait_closed(self):
 		'''
 		https://docs.python.org/3/library/asyncio-stream.html#asyncio.StreamWriter.wait_closed
 		'''
 
-		if self._closed:
+		ce = self._closed_event
+		if ce is None:
 			return
 
-		await self._closed_event.wait()
+		await ce.wait()
 
 class WSFWDCommon:
 	'''
@@ -683,6 +687,9 @@ class Test(unittest.IsolatedAsyncioTestCase):
 			stdin.close()
 			await stdin.wait_closed()
 
+			# that it can be awaited multiple times
+			await stdin.wait_closed()
+
 			self.assertEqual(await stdout.read(), b'')
 
 			self.assertEqual(await proc.wait(), 0)