anchor.diff:        expect(printer('ab'), 'ab');
         expect(printer('abc'), 'bc');
         expect(printer('abcd'), 'cd');
  +      expect(printer.toString(), startsWith('TakeLastPrinter'));
       });
       test('skip', () {
         final printer = standardString.skip(2);
  
positive.code:       expect(printer('ab'), '');
        expect(printer('abc'), 'a');
        expect(printer('abcd'), 'ab');
      });
    });
    group('trim', () {
  
negative.code:       expect(printer('ab'), '');
        expect(printer('abc'), 'c');
        expect(printer('abcd'), 'cd');
        expect(printer.toString(), startsWith('SkipPrinter'));
      });
      test('skipLast', () {
        final printer = standardString.skipLast(2);
  