diff --git a/Lib/test/test_asyncio/test_subprocess.py b/Lib/test/test_asyncio/test_subprocess.py
index e8822c36698..0b2b17a4c3f 100644
--- a/Lib/test/test_asyncio/test_subprocess.py
+++ b/Lib/test/test_asyncio/test_subprocess.py
@@ -210,6 +210,7 @@ class SubprocessMixin:
 
         @asyncio.coroutine
         def write_stdin(proc, data):
+            yield from asyncio.sleep(0.5, loop=self.loop)
             proc.stdin.write(data)
             yield from proc.stdin.drain()