A sample code to break CKE4 mode creation

destroy2.js

/* bender-tags: editor,unit */
/* bender-ckeditor-plugins: divarea */

( function() {
	'use strict';

	bender.test( {
		// (#2257)
		'test destroy editor on instance created': function() {
			var editor = CKEDITOR.replace( 'destroyed' ),
				wysiwygModeSpy;

			editor.on( 'destroy', function() {
				resume( function() {
					assert.isFalse( wysiwygModeSpy.threw(), 'WYSIWYG mode function should not throw an exception' );
				} );
			} );

			editor.on( 'beforeSetMode', function() {
				wysiwygModeSpy = sinon.spy( editor._.modes, 'wysiwyg' );

				editor.destroy();
			} );

			wait();
		}
	} );
} )();