Fix #13741. Make wrap/unwrap methods optional; close gh-1236.

move size() test to unit/deprecated;
don't use size() in other tests;
make 2 unit tests actually fire;
code cleanup

src/wrap.js

@@ -0,0 +1,66 @@
+jQuery.fn.extend({
+	wrapAll: function( html ) {
+		if ( jQuery.isFunction( html ) ) {
+			return this.each(function(i) {
+				jQuery(this).wrapAll( html.call(this, i) );
+			});
+		}
+
+		if ( this[0] ) {
+			// The elements to wrap the target around
+			var wrap = jQuery( html, this[0].ownerDocument ).eq(0).clone(true);
+
+			if ( this[0].parentNode ) {
+				wrap.insertBefore( this[0] );
+			}
+
+			wrap.map(function() {
+				var elem = this;
+
+				while ( elem.firstChild && elem.firstChild.nodeType === 1 ) {
+					elem = elem.firstChild;
+				}
+
+				return elem;
+			}).append( this );
+		}
+
+		return this;
+	},
+
+	wrapInner: function( html ) {
+		if ( jQuery.isFunction( html ) ) {
+			return this.each(function(i) {
+				jQuery(this).wrapInner( html.call(this, i) );
+			});
+		}
+
+		return this.each(function() {
+			var self = jQuery( this ),
+				contents = self.contents();
+
+			if ( contents.length ) {
+				contents.wrapAll( html );
+
+			} else {
+				self.append( html );
+			}
+		});
+	},
+
+	wrap: function( html ) {
+		var isFunction = jQuery.isFunction( html );
+
+		return this.each(function(i) {
+			jQuery( this ).wrapAll( isFunction ? html.call(this, i) : html );
+		});
+	},
+
+	unwrap: function() {
+		return this.parent().each(function() {
+			if ( !jQuery.nodeName( this, "body" ) ) {
+				jQuery( this ).replaceWith( this.childNodes );
+			}
+		}).end();
+	}
+});