Add required test suite and websocket fixes

tests/test_load_simulation.py

@@ -1,2 +1,49 @@
-def test_placeholder_load_simulation():
-    assert True
+import time
+
+from conftest import create_session, join_student
+
+
+def test_load_simulation_50_students_full_quiz_and_autoclose(client, sample_pool):
+    sid = create_session(client, sample_pool)
+    rooms = client.app.state.rooms
+    sockets = []
+    try:
+        for idx in range(50):
+            join_student(client, sid, f"s{idx:02d}", f"Student {idx:02d}")
+            ws = client.websocket_connect(f"/ws/student/{sid}").__enter__()
+            sockets.append(ws)
+            assert ws.receive_json()["type"] == "state"
+
+        for question_idx in range(5):
+            client.portal.call(rooms.open_question, sid, question_idx, 1)
+            for ws in sockets:
+                assert ws.receive_json()["type"] == "question_open"
+            for idx, ws in enumerate(sockets):
+                answer = sample_pool["questions"][question_idx]["correct"] if idx % 3 else "A"
+                ws.send_json({"type": "submit", "question_idx": question_idx, "answer": answer})
+                assert ws.receive_json()["type"] == "submit_ack"
+            if question_idx == 4:
+                started = time.monotonic()
+                for ws in sockets:
+                    message = ws.receive_json()
+                    assert message["type"] == "question_closed"
+                assert time.monotonic() - started < 2
+            else:
+                client.portal.call(rooms.close_question, sid)
+                for ws in sockets:
+                    assert ws.receive_json()["type"] == "question_closed"
+                client.portal.call(rooms.next_question, sid)
+                for ws in sockets:
+                    assert ws.receive_json()["type"] == "between_questions"
+
+        client.portal.call(rooms.end_session, sid)
+        for ws in sockets:
+            assert ws.receive_json()["type"] == "session_ended"
+
+        csv_lines = client.get(f"/admin/api/sessions/{sid}/csv").text.strip().splitlines()
+        assert len(csv_lines) == 1 + 50 * 5
+        stats = client.get(f"/api/session/{sid}/stats?question_idx=4").json()
+        assert stats["top5"]
+    finally:
+        for ws in sockets:
+            ws.__exit__(None, None, None)