 data.b = () => [data.a, data.a].join(',');

      test(
        p5.innerText === ['stuff', 'stuff'].join(','),
        'p#5 (computed) data set'
      );
      data.a = 'thing';
      test(
        p5.innerText === ['thing', 'thing'].join(','),
        'p#5 (computed) data updated'
      );

      delete data.a;
      test(
        p5.innerText === ['thing', 'thing'].join(','),
        'p#5 (computed) data save after a delete'
      );

      delete data.b;
      test(!p5.isConnected, 'p#5 not connected af