anchor.diff:  
   library frame_test;
   
  +import 'dart:io';
   import 'dart:uri';
   
   import 'package:pathos/path.dart' as path;
  
positive.code:       expect(new Frame.parse('#0 Foo '
                '(http://dartlang.org/thing.dart:5:10)').location,
            equals('http://dartlang.org/thing.dart 5:10'));
        var absolute = path.absolute(path.join('foo', 'bar.dart'));
        expect(new Frame.parse('#0 Foo (file://$absolute:1:2)').location,
            equals('${path.join('foo', 'bar.dart')} 1:2'));
      });
  
  
negative.code:     // TODO(nweiz): use URL-style paths when such a thing exists.
      var builder = new path.Builder(style: path.Style.posix);
      expect(builder.basename(frame.uri.path), equals('frame_test.dart'));
      expect(frame.line, equals(16));
      expect(frame.column, equals(5));
      expect(frame.member, equals('getStackFrame'));
    });
  