Tests for qx.ui.form.RadioButton. qx.ui.form.RadioButton extends qx.ui.basic.Atom and so it inherits all the options and properties defined there.
To group multiple QxRadioButtons you must define a instance of qx.manager.selection.RadioManager and add them to this new instance. All QxRadioButtons assigned to the same group make sure that only one of them is checked at the same time.