Kill written to /ctl is answered before the editor quits

The write got EPIPE: Kill set quit, the request waited for the editor to
settle its effects, and the editor quit and cut the connections first.
A write that quits the editor is now answered at once, and the listener
lets pending answers out (up to 200 ms) before it stops the runner.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 20 insertions, 0 deletions

diff --git a/test/fs.py b/test/fs.py
index c56c6298..e9540169 100644
--- a/test/fs.py
+++ b/test/fs.py
@@ -405,9 +405,29 @@ def run_file(binary):
                 assert closing == [b'error shell gone\n'], closing
 
 
+def kill_answers(binary):
+    """Kill written to /ctl is answered before the editor quits."""
+    with tempfile.TemporaryDirectory(prefix='pardes-kill-') as directory:
+        seen = {}
+        with session(binary, Path(directory), 'kill', terminal=seen) as (client, _):
+            client.write('/ctl', b'Kill\n')
+            deadline = time.monotonic() + 5
+            while time.monotonic() < deadline:
+                try:
+                    # a zombie has quit; the session reaps it
+                    if Path(f'/proc/{seen["pid"]}/stat').read_text().split(') ')[1][0] == 'Z':
+                        break
+                except FileNotFoundError:
+                    break
+                time.sleep(.01)
+            else:
+                raise AssertionError('Kill did not quit the editor')
+
+
 def test(binary, quic=False):
     started = time.monotonic()
     run_file(binary)
+    kill_answers(binary)
     for options, message in [
         (['--fs'], b'no such option'),
         (['--fs9'], b'no such option'),