Function append

src/tests/frontend/runner.js:135–139

(text)

    const $console = $('#console');
    const append = (text) => {
      // Indent each line.
      const lines = text.split('\n').map((line) => ' '.repeat(level * 2) + line);
      $console.append(document.createTextNode(`${lines.join('\n')}\n`));
    };

    const total = runner.total;
    runner.on('end', () => {