2 files changed, 32 insertions, 0 deletions
diff --git a/lib/project/tests/test_gui.py b/lib/project/tests/test_gui.py
index e490e99..2f17549 100644
--- a/lib/project/tests/test_gui.py
+++ b/lib/project/tests/test_gui.py
@@ -1,5 +1,6 @@
 """Optional GUI API, origin boundary, uploads, snapshots, and real sound previews."""
 from dataclasses import asdict
+import socket
 import hashlib
 from pathlib import Path
 import struct
@@ -13,6 +14,7 @@ pytest.importorskip("fastapi")
 from fastapi.testclient import TestClient
 
 from producer.config import Settings
+from producer import gui as gui_module
 from producer.gui import create_app
 from producer import gui_jobs
 
@@ -280,3 +282,32 @@ def test_waveform_buffers_bounded_and_scan_cancellable(wav, monkeypatch):
     with pytest.raises(gui_jobs.Cancelled):
         gui_jobs.waveform(source, cancel)
     assert reads == [65536]
+
+
+def test_serve_listener_allows_quick_restart(monkeypatch):
+    """serve() must set SO_REUSEADDR: without it a restart right after Ctrl+C
+    fails while connections the server closed first sit in TIME_WAIT."""
+    captured = {}
+
+    class FakeServer:
+        def __init__(self, config):
+            pass
+        def run(self, sockets):
+            captured["sockets"] = sockets
+            (sock,) = sockets
+            # Sample the state while serve() still holds the socket open.
+            captured["reuseaddr"] = sock.getsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR)
+            captured["address"] = sock.getsockname()
+
+    class FakeConfig:
+        def __init__(self, *args, **kwargs):
+            pass
+
+    class FakeUvicorn:
+        Server, Config = FakeServer, FakeConfig
+
+    monkeypatch.setitem(__import__("sys").modules, "uvicorn", FakeUvicorn)
+    monkeypatch.setattr(gui_module, "create_app", lambda *a, **k: object())
+    gui_module.serve(18765)
+    assert captured["reuseaddr"] == 1
+    assert captured["address"] == ("127.0.0.1", 18765)
diff --git a/lib/project/tests/test_gui_browser.py b/lib/project/tests/test_gui_browser.py
index 385de44..efc6e55 100644
--- a/lib/project/tests/test_gui_browser.py
+++ b/lib/project/tests/test_gui_browser.py
@@ -8,6 +8,7 @@ The long overview case uses mocked fixed-size scan metadata, not 4-hour AI infer
 from dataclasses import asdict
 import hashlib
 import json
+import os
 from pathlib import Path
 import socket
 import threading