anchor.diff:  
             return _printStreams();
           }).then((_) {
  -          registerException(new ExpectException("Process $name ended "
  +          registerException(new TestFailure("Process $name ended "
                 "earlier than scheduled with exit code $exitCode"));
           });
         }).catchError((e) => registerException(e.error, e.stackTrace));
  
positive.code:           failures.addAll(result.stderr.map((line) => '| $line'));
          }
  
          throw new ExpectException(failures.join('\n'));
        }
  
        return null;
  
negative.code:       var text = readTextFile(file);
        if (text == textContents) return null;
  
        throw new TestFailure(
            'File $file should contain:\n\n$textContents\n\n'
            'but contained:\n\n$text');
      });
  