1 files changed, 60 insertions, 0 deletions
diff --git a/app/tests/test_backends_servers.py b/app/tests/test_backends_servers.py
index 201d5b6..8eaf53f 100644
--- a/app/tests/test_backends_servers.py
+++ b/app/tests/test_backends_servers.py
@@ -1,5 +1,7 @@
 """Tests for the server lifecycle module (backends/servers.py)."""
 
+import os
+import signal
 import tempfile
 import unittest
 from pathlib import Path
@@ -225,6 +227,64 @@ class StopTests(unittest.TestCase):
         self.assertFalse((self.dir / "test-server.pid").exists())
 
 
+class ReapTests(unittest.TestCase):
+    """_reap_exited: an exited child must stop counting as alive."""
+
+    def test_true_when_child_exited(self):
+        with patch("os.waitpid", return_value=(4242, 0)) as mk:
+            self.assertTrue(servers._reap_exited(4242))
+        mk.assert_called_once_with(4242, os.WNOHANG)
+
+    def test_false_while_still_running(self):
+        # (0, 0) is WNOHANG's "still running" answer.
+        with patch("os.waitpid", return_value=(0, 0)):
+            self.assertFalse(servers._reap_exited(4242))
+
+    def test_false_when_not_our_child(self):
+        with patch("os.waitpid", side_effect=ChildProcessError):
+            self.assertFalse(servers._reap_exited(4242))
+
+
+class KillPidTests(unittest.TestCase):
+    """_kill_pid: the reap check ends the grace wait before SIGKILL."""
+
+    def test_reaped_child_ends_wait_without_sigkill(self):
+        with patch("os.getpgid", return_value=4242), \
+                patch("os.killpg") as mk_killpg, \
+                patch("os.waitpid", return_value=(4242, 0)) as mk_waitpid, \
+                patch("time.sleep") as mk_sleep:
+            ok = servers._kill_pid(4242)
+        self.assertTrue(ok)
+        mk_killpg.assert_called_once_with(4242, signal.SIGTERM)
+        mk_waitpid.assert_called_once_with(4242, os.WNOHANG)
+        mk_sleep.assert_not_called()
+
+    def test_escalates_to_sigkill_when_child_stays_alive(self):
+        with patch("os.getpgid", return_value=4242), \
+                patch("os.killpg") as mk_killpg, \
+                patch("os.waitpid", return_value=(0, 0)), \
+                patch("time.sleep"):
+            ok = servers._kill_pid(4242)
+        self.assertTrue(ok)
+        calls = mk_killpg.call_args_list
+        self.assertEqual(calls[0].args, (4242, signal.SIGTERM))
+        self.assertEqual(calls[-1].args, (4242, signal.SIGKILL))
+
+    def test_foreign_child_falls_back_to_group_probe(self):
+        # ChildProcessError from waitpid (not our child / already reaped):
+        # the killpg(0) probe decides; a vanished group ends the wait.
+        with patch("os.getpgid", return_value=4242), \
+                patch("os.killpg",
+                      side_effect=[None, ProcessLookupError]) as mk_killpg, \
+                patch("os.waitpid", side_effect=ChildProcessError), \
+                patch("time.sleep"):
+            ok = servers._kill_pid(4242)
+        self.assertTrue(ok)
+        calls = mk_killpg.call_args_list
+        self.assertEqual(calls[0].args, (4242, signal.SIGTERM))
+        self.assertEqual(calls[-1].args, (4242, 0))
+
+
 class ManagesTests(unittest.TestCase):
     """manages(): a live recorded pid marks a server as ours."""