gistfile1.txt

exports.testButtonToOpenXToClose = function(assert, done) {
  const { Sidebar } = require('sdk/ui/sidebar');
  let testName = 'testButtonToOpenXToClose';

  let title = testName;
  let url = 'data:text/html;charset=utf-8,' + testName;
  let window = getMostRecentBrowserWindow();

  let sidebar = Sidebar({
    id: testName,
    title: testName,
    icon: BLANK_IMG,
    url: url,
    onShow: function() {
      assert.equal(button.getAttribute('checked'), 'true', 'button is checked');
      let closeButton = window.document.querySelector('#sidebar-header > toolbarbutton.tabs-closebutton');
      simulateCommand(button);
    },
    onHide: function() {
      assert.equal(button.getAttribute('checked') || 'false', 'false', 'button is not checked');
      sidebar.destroy();
      done();
    }
  });

  let { node: button } = getWidget(sidebar.id, window);
  assert.equal(button.getAttribute('checked') || 'false', 'false', 'button is not checked');
  simulateCommand(button);
}