Add required test suite and websocket fixes

tests/test_csv_export.py

@@ -1,2 +1,17 @@
-def test_placeholder_csv_export():
-    assert True
+from conftest import create_session, join_student
+
+
+def test_csv_export_contains_one_row_per_submission(client, sample_pool):
+    sid = create_session(client, sample_pool)
+    join_student(client, sid, "s1", "Student One")
+    rooms = client.app.state.rooms
+    client.portal.call(rooms.open_question, sid, 0, 2)
+    ack = client.portal.call(rooms.submit_answer, sid, "s1", 0, "B")
+    assert ack["type"] == "submit_ack"
+    client.portal.call(rooms.close_question, sid)
+
+    response = client.get(f"/admin/api/sessions/{sid}/csv")
+    lines = response.text.strip().splitlines()
+    assert lines[0] == "sid,student_id,name,question_idx,answer,elapsed_ms,score,status"
+    assert len(lines) == 2
+    assert ",s1,Student One,0,B," in lines[1]