text: {
    var tile = d3_hierarchy.treemapSquarify,
      root = {
        value: 0,
        children: [
          {
            value: 0
          },
          {
            value: 0
          }
        ]
      };
    tile(root, 0, 0, 0, 4);
    test.deepEqual(root.children.map(round), [
      {
        x0: 0.0,
        x1: 0.0,
        y0: 0.0,
        y1: 4.0
      },
      {
        x0: 0.0,
        x1: 0.0,
        y0: 0.0,
        y1: 4.0
      }
    ]);
    test.end();
  }
  