Websockets instead of polling

tests/test_game.py

@@ -1210,3 +1210,39 @@ def test_event_log_pagination(session):
     exact, have_more = crud.get_events_page(session, game.id, before=1020.0, limit=20)
     assert not have_more
     assert [e.message for e in exact] == [f"event {i}" for i in range(20)]
+
+def test_websocket_state_push():
+    """A successful POST under /api/game/{gid}/ pings that game's websockets."""
+    from fastapi.testclient import TestClient
+    from sqlmodel.pool import StaticPool
+    from pirats.main import app
+    from pirats.database import get_session
+
+    engine = create_engine(
+        "sqlite://",
+        connect_args={"check_same_thread": False},
+        poolclass=StaticPool,
+    )
+    SQLModel.metadata.create_all(engine)
+
+    def override_session():
+        with Session(engine) as s:
+            yield s
+
+    app.dependency_overrides[get_session] = override_session
+    try:
+        client = TestClient(app)
+        gid = client.post("/api/game", data={"crew_name": "Testers"}).json()["id"]
+
+        with client.websocket_connect(f"/api/game/{gid}/ws") as ws:
+            res = client.post(f"/api/game/{gid}/join", data={"name": "Carlos"})
+            assert res.status_code == 200
+            assert ws.receive_json() == {"type": "state_changed"}
+
+            # A POST for a different game must not ping this socket
+            other_gid = client.post("/api/game", data={"crew_name": "Others"}).json()["id"]
+            client.post(f"/api/game/{other_gid}/join", data={"name": "Barry"})
+            client.post(f"/api/game/{gid}/join", data={"name": "Jaspar"})
+            assert ws.receive_json() == {"type": "state_changed"}
+    finally:
+        app.dependency_overrides.clear()