Unittest for jquery#1988

Author: fglueck

tests/unit/dialog/options.js

@@ -569,4 +569,19 @@ QUnit.test( "Open followed by close during show effect", function( assert ) {
 	}, 100 );
 } );
 
+QUnit.test( "Dialog can't break out containment", function( assert ) {
+	assert.expect( 1 );
+	var box = $( '<div id="xxx"></div>' ).css( {
+			height: '500px',border: '0px, margin:'0px', width:'500px', position: 'absolute', bottom: '0px', right: '0px', left: '50px', top: '50px'
+		} ).appendTo( "body" ),
+		element = $('<div>X</div>').dialog({containment: box, position: { at: "left top", of: box}}), // open on left top corner
+		dlg = element.dialog('widget'),
+		offsetAfter,
+		expected = box.offset();
+		
+		testHelper.drag( element, '.ui-dialog-titlebar', -200, -200);  // try to move out
+	    offsetAfter = dlg.offset(); // should be the same 
+	assert.deepEqual( offsetAfter, expected, "compare offset" );
+} );
+	
 } );