Function rename

ts/__tests__/util.test.ts:16–18

(a: string, b: string)

  ).toEqual('dir/file.json');

  const rename = (a: string, b: string) => {
    return filePairDisplayName({...props, type: 'move', a, b, num_add: 0, num_delete: 0});
  };
  expect(rename('file.json', 'renamed.json')).toEqual('{file → renamed}.json');
  expect(rename('dir/file.json', 'dir/renamed.json')).toEqual('dir/{file → renamed}.json');
  expect(rename('file.json', 'dir/file.json')).toEqual('{ → dir/}file.json');