Use jest for unit test

tests/unit/utils.ts

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+import { Torrent } from '@/types';
+
+const emptyTorrent: Torrent = {
+  hash: '',
+  added_on: 0,
+  amount_left: 0,
+  auto_tmm: false,
+  availability: 0,
+  category: '',
+  completed: 0,
+  completion_on: 0,
+  dl_limit: 0,
+  dlspeed: 0,
+  downloaded: 0,
+  downloaded_session: 0,
+  eta: 0,
+  f_l_piece_prio: false,
+  force_start: false,
+  last_activity: 0,
+  magnet_uri: '',
+  max_ratio: 0,
+  max_seeding_time: 0,
+  name: '',
+  num_complete: 0,
+  num_incomplete: 0,
+  num_leechs: 0,
+  num_seeds: 0,
+  priority: 0,
+  progress: 0,
+  ratio: 0,
+  ratio_limit: 0,
+  save_path: '',
+  seeding_time_limit: 0,
+  seen_complete: 0,
+  seq_dl: false,
+  size: 0,
+  state: '',
+  super_seeding: false,
+  tags: '',
+  time_active: 0,
+  total_size: 0,
+  tracker: '',
+  up_limit: 0,
+  uploaded: 0,
+  uploaded_session: 0,
+  upspeed: 0,
+};
+
+export function mockTorrent(props: Partial<Torrent>): Torrent {
+  return Object.assign({}, emptyTorrent, props);
+}