             context("when adding properties") {
                 it("should be added to style") {
                     let font = UIFont.systemFontOfSize(22)
-                    var newStyle: StyleRule = [ .Font: font ]
+                    let newStyle: StyleRule = [ .Font: font ]
 
                     expect(newStyle.extends(style).font) == font
                 }


            context("when extending properties") {
                it("it should take new value") {
                    var newStyle: StyleRule = [ .Color: UIColor.blackColor() ]

                    expect(newStyle.extends(style).color) == UIColor.blackColor()
                }

                    it("should merge valid ones") {
                        var newStyle: StyleRule = [:]

                        newStyle = newStyle.extends(nil, style)
                        expect(newStyle.color) == UIColor.blueColor()
                    }

                    it("should add all properties") {
                        var newStyle: StyleRule = [:]

                        newStyle = newStyle.extends(style, [ .TintColor: UIColor.greenColor() ])

                        expect(newStyle.color) == UIColor.blueColor()
                        expect(newStyle.tintColor) == UIColor.greenColor()
