diff --git a/tests/conftest.py b/tests/conftest.py
index 0141d434..3ceb878e 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -124,19 +124,24 @@ def _smart_watchdog_exit() -> None:
 threading.Thread(target=_smart_watchdog_exit, daemon=True, name="conftest-smart-watchdog").start()
 
 def _unconditional_watchdog_exit() -> None:
- """Hard fail-safe: fires regardless of pytest state after 90s total.
+ """Hard fail-safe: also signal-based, but with a much longer
+ timeout than the smart watchdog.
 
- The smart watchdog (above) is gated on pytest_unconfigure setting
- _pytest_finished_event. If something is hung BEFORE pytest
- unconfigure runs (e.g., the conftest's own _warmup_app_controller
- hangs in wait_for_warmup during startup, or pytest never reaches
- its unconfigure phase), the smart watchdog's first wait
- blocks. This unconditional watchdog is the sledgehammer: 90s
- from conftest load, fire os._exit(2) regardless.
+ The smart watchdog (above) uses 300s. This sledgehammer waits
+ 900s (15 minutes) for the same signal, so a long-running test
+ can take up to 15 minutes before we declare it a hang. The
+ only case this catches that the smart doesn't: pytest finishes
+ but the test session is so long the smart's 300s expires first.
+ In that case we still want the runner to move on.
+
+ If the signal never fires (true hang), os._exit(2) so the runner
+ catches it as CalledProcessError.
  """
+ if not _pytest_finished_event.wait(timeout=900.0):
+  os._exit(2)
  import time
- time.sleep(90.0)
- os._exit(2)
+ time.sleep(5.0)
+ os._exit(0)
 
 threading.Thread(target=_unconditional_watchdog_exit, daemon=True, name="conftest-unconditional-watchdog").start()