|  | // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file | 
|  | // for details. All rights reserved. Use of this source code is governed by a | 
|  | // BSD-style license that can be found in the LICENSE file. | 
|  |  | 
|  | import "package:expect/expect.dart"; | 
|  |  | 
|  | void not1() { | 
|  | var x = !true; | 
|  | Expect.equals(false, x); | 
|  | } | 
|  |  | 
|  | void not2() { | 
|  | var x = true; | 
|  | var y = !x; | 
|  | Expect.equals(false, y); | 
|  | } | 
|  |  | 
|  | void not3() { | 
|  | var x = true; | 
|  | var y = !x; | 
|  | var z = !y; | 
|  | Expect.equals(true, z); | 
|  | } | 
|  |  | 
|  | void not4() { | 
|  | var x = true; | 
|  | if (!x) Expect.fail('unreachable'); | 
|  | Expect.equals(true, x); | 
|  | } | 
|  |  | 
|  | void main() { | 
|  | not1(); | 
|  | not2(); | 
|  | not3(); | 
|  | not4(); | 
|  | } |