anchor.diff:  import "package:async_helper/async_helper.dart";
   import "package:expect/expect.dart";
   
  -import "process_test_util.dart";
  -
   void test() {
     asyncStart();
     var script =
  
positive.code:   future.then((process) {
      Expect.isNotNull(process.pid);
      Expect.isTrue(process.pid is int);
      Expect.isNull(process.exitCode);
      Expect.isNull(process.stderr);
      Expect.isNull(process.stdin);
      Expect.isNull(process.stdout);
      Expect.isTrue(process.kill());
    }).whenComplete(() {
      asyncEnd();
  
negative.code:   future.then((process) {
      Expect.isNotNull(process.pid);
      Expect.isTrue(process.pid is int);
      Expect.throwsStateError(() => process.exitCode);
      var message = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
      process.stdin.add(message);
      process.stdin.flush().then((_) => process.stdin.close());
  