Add required test suite and websocket fixes

tests/test_state_machine.py

@@ -1,2 +1,45 @@
-def test_placeholder_state_machine():
-    assert True
+from conftest import create_session, join_student
+
+
+def test_full_lifecycle_with_three_students(client, sample_pool):
+    sid = create_session(client, sample_pool)
+    rooms = client.app.state.rooms
+    sockets = []
+    for idx in range(3):
+        join_student(client, sid, f"s{idx}", f"Student {idx}")
+        ws = client.websocket_connect(f"/ws/student/{sid}").__enter__()
+        sockets.append(ws)
+        assert ws.receive_json()["state"] == "lobby"
+
+    try:
+        client.portal.call(rooms.open_question, sid, 0, 2)
+        for ws in sockets:
+            assert ws.receive_json()["type"] == "question_open"
+        for idx, ws in enumerate(sockets):
+            ws.send_json({"type": "submit", "question_idx": 0, "answer": "B" if idx < 2 else "A"})
+            assert ws.receive_json()["type"] == "submit_ack"
+
+        client.portal.call(rooms.close_question, sid)
+        for ws in sockets:
+            assert ws.receive_json()["type"] == "question_closed"
+        session = client.portal.call(rooms.get_session, sid)
+        assert session["state"] == "question_closed"
+
+        client.portal.call(rooms.next_question, sid)
+        for ws in sockets:
+            assert ws.receive_json()["type"] == "between_questions"
+        assert client.portal.call(rooms.get_session, sid)["state"] == "between_questions"
+
+        client.portal.call(rooms.open_question, sid, 1, 2)
+        for ws in sockets:
+            assert ws.receive_json()["type"] == "question_open"
+        client.portal.call(rooms.end_session, sid)
+        for ws in sockets:
+            message = ws.receive_json()
+            assert message["type"] in {"question_closed", "session_ended"}
+            if message["type"] == "question_closed":
+                assert ws.receive_json()["type"] == "session_ended"
+        assert client.portal.call(rooms.get_session, sid)["state"] == "finished"
+    finally:
+        for ws in locals().get("sockets", []):
+            ws.__exit__(None, None, None)