Fix #10812, let .before() and .after() work on empty collections.

src/manipulation.js

@@ -154,7 +154,7 @@ jQuery.fn.extend({
 				this.parentNode.insertBefore( elem, this );
 			});
 		} else if ( arguments.length ) {
-			var set = jQuery(arguments[0]);
+			var set = jQuery.clean( arguments );
 			set.push.apply( set, this.toArray() );
 			return this.pushStack( set, "before", arguments );
 		}
@@ -167,7 +167,7 @@ jQuery.fn.extend({
 			});
 		} else if ( arguments.length ) {
 			var set = this.pushStack( this, "after", arguments );
-			set.push.apply( set, jQuery(arguments[0]).toArray() );
+			set.push.apply( set, jQuery.clean(arguments) );
 			return set;
 		}
 	},

test/unit/manipulation.js

@@ -794,6 +794,14 @@ test("before(Function)", function() {
 	testBefore(functionReturningObj);
 })
 
+test("before and after w/ empty object (#10812)", function() {
+	expect(2);
+
+	var res = jQuery( "#notInTheDocument" ).before( "(" ).after( ")" );
+	equal( res.length, 2, "didn't choke on empty object" );
+	equal( res.wrap("<div/>").parent().text(), "()", "correctly appended text" );
+});
+
 test("insertBefore(String|Element|Array&lt;Element&gt;|jQuery)", function() {
 	expect(4);
 	var expected = "This is a normal link: bugaYahoo";