anchor.diff:  
   main() {
     testImmediate();
  +  testNeverComplete();
  +  testComplete();
  +  testCompleteWithHandlerBeforeComplete();
  +  testCompleteWithHandlerAfterComplete();
  +  testCompleteManyHandlers();
  +  testException();
  +  testExceptionHandler();
  +  testExceptionHandlerReturnsTrue();
  +  testExceptionHandlerReturnsTrue2();
  +  testExceptionHandlerReturnsFalse();
  +  testExceptionHandlerReturnsFalse2();
     testTransformSuccess();
     testTransformFutureFails();
     testTransformTransformerFails();
  
positive.code: // 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.
  
  testImmediate() {
    final future = new Future<String>.immediate("42");
    Expect.isTrue(future.isComplete);
    var value = null;
    future.then((x) => value = x);
    Expect.equals("42", value);
  }
  
  testTransformSuccess() {
    final completer = new Completer<String>();
  
negative.code:   Expect.equals(error, transformedFuture.exception);
  }
  
  // Tests for Future.chain
  
  testChainSuccess() {
    final completerA = new Completer<String>();
    final completerB = new Completer<String>();
  