Datepicker: Make use of Calendar widget icons option

Fix missing classes options defaults in tests.

Author: fnagel

tests/unit/datepicker/common.js

@@ -8,10 +8,20 @@ common.testWidget( "datepicker", {
 	defaults: {
 		appendTo: null,
 		buttons: [],
-		classes: {},
+		classes: {
+			"ui-calendar": "ui-corner-all",
+			"ui-calendar-header-first": "ui-corner-left",
+			"ui-calendar-header-last": "ui-corner-right",
+			"ui-calendar-prev": "ui-corner-all",
+			"ui-calendar-next": "ui-corner-all"
+		},
 		disabled: false,
 		dateFormat: { date: "short" },
 		eachDay: $.noop,
+		icons: {
+			prevButton: "ui-icon-circle-triangle-w",
+			nextButton: "ui-icon-circle-triangle-e"
+		},
 		labels: {
 			"datePickerRole": "date picker",
 			"nextText": "Next",

ui/widgets/datepicker.js

@@ -57,7 +57,7 @@ var widget = $.widget( "ui.datepicker", {
 	},
 
 	calendarOptions: [ "buttons", "classes", "disabled", "dateFormat", "eachDay",
-		"labels", "locale", "max", "min", "numberOfMonths", "showWeek" ],
+		"icons", "labels", "locale", "max", "min", "numberOfMonths", "showWeek" ],
 
 	_create: function() {
 		this.suppressExpandOnFocus = false;