 
     func testAndProperty() {
         let lhs = MutableProperty(false), rhs = MutableProperty(false)
-        let and = AndProperty(lhs: lhs, rhs: rhs)
+        let and = lhs.and(rhs)
 
         var current: Bool!
         and.producer.startWithNext { current = $0 }


    func testNotProperty() {
        let source = MutableProperty(false)
        let not = NotProperty(property: source)

        var current: Bool!
        not.producer.startWithNext { current = $0 }


    func testOrProperty() {
        let lhs = MutableProperty(true), rhs = MutableProperty(true)
        let or = lhs.or(rhs)

        var current: Bool!
        or.producer.startWithNext { current = $0 }
