Add required test suite and websocket fixes

tests/test_ws_student.py

@@ -1,2 +1,37 @@
-def test_placeholder_ws_student():
-    assert True
+import pytest
+from starlette.websockets import WebSocketDisconnect
+
+from conftest import create_session, join_student
+
+
+def test_student_ws_requires_cookie(client, sample_pool):
+    sid = create_session(client, sample_pool)
+    with pytest.raises(WebSocketDisconnect) as exc:
+        with client.websocket_connect(f"/ws/student/{sid}"):
+            pass
+    assert exc.value.code == 4001
+
+
+def test_student_ws_initial_state_submit_and_closed_reject(client, sample_pool):
+    sid = create_session(client, sample_pool)
+    join_student(client, sid, "s1", "Student One")
+    with client.websocket_connect(f"/ws/student/{sid}") as ws:
+        state = ws.receive_json()
+        assert state["type"] == "state"
+        assert state["state"] == "lobby"
+
+        rooms = client.app.state.rooms
+        client.portal.call(rooms.open_question, sid, 0, 2)
+        opened = ws.receive_json()
+        assert opened["type"] == "question_open"
+        ws.send_json({"type": "submit", "question_idx": 0, "answer": "B"})
+        ack = ws.receive_json()
+        assert ack["type"] == "submit_ack"
+        assert ack["score"] > 0
+
+        client.portal.call(rooms.close_question, sid)
+        closed = ws.receive_json()
+        assert closed["type"] == "question_closed"
+        ws.send_json({"type": "submit", "question_idx": 0, "answer": "B"})
+        error = ws.receive_json()
+        assert error["code"] == "not_open"