code: function drawFaviconArc(context, total, start, length, color) {
      var arcStart = ARC_OFFSET + Math.PI * 2 * (start / total);
      var arcEnd = ARC_OFFSET + Math.PI * 2 * ((start + length) / total);
      context.beginPath();
      context.strokeStyle = color;
      context.lineWidth = ARC_WIDTH;
      context.arc(16, 16, 16 - ARC_WIDTH / 2, arcStart, arcEnd);
      context.stroke();
  }
docs: Draws an arc for the favicon status, relative to the total number of tests.