it('should fail if table header has no child nodes', function () {
    var node = new axe.SerialVirtualNode({
      nodeName: 'th',
      attributes: {}
    });
    node.children = [];

    var results = axe.runVirtualRule('empty-table-header', node);

    assert.lengthOf(results.passes, 0);
    assert.lengthOf(results.violations, 1);
    assert.lengthOf(results.incomplete, 0);
  });