assignment.put("XWiki.JavaScriptExtension_0_code", "var tmp = alice;\nalice = 2 * bob;\nbob = tmp;");
form.fillFieldsByName(assignment);
objectEditPage.clickSaveAndContinue();
// Create class.
ClassEditPage classEditPage = objectEditPage.editClass();
classEditPage.addProperty("age", "Number");
classEditPage.addProperty("color", "String");
classEditPage.getNumberClassEditElement("age").setNumberType("integer");
classEditPage.clickSaveAndContinue();
classEditPage.deleteProperty("color");