anchor.diff:  }
   
   Future _generateTest(CommentGenerator gen, String expectedContent) async {
  -  var srcs = _createPackageStub(pkgName);
  +  var srcs = _createPackageStub();
     var builder = new PartBuilder([gen]);
   
     await testBuilder(builder, srcs,
  -      generateFor: new Set.from(['$pkgName|lib/test_lib.dart']),
  +      generateFor: new Set.from(['$_pkgName|lib/test_lib.dart']),
         outputs: {
  -        '$pkgName|lib/test_lib.g.dart': decodedMatches(expectedContent),
  +        '$_pkgName|lib/test_lib.g.dart': decodedMatches(expectedContent),
         },
         onLog: (log) => fail('Unexpected log message: ${log.message}'));
   }
   
  -/// Creates a package using [pkgName].
  -Map<String, String> _createPackageStub(String pkgName,
  +Map<String, String> _createPackageStub(
       {String testLibContent, String testLibPartContent}) {
     return {
  -    '$pkgName|lib/test_lib.dart': testLibContent ?? _testLibContent,
  -    '$pkgName|lib/test_lib.g.dart': testLibPartContent ?? _testLibPartContent,
  +    '$_pkgName|lib/test_lib.dart': testLibContent ?? _testLibContent,
  +    '$_pkgName|lib/test_lib.g.dart': testLibPartContent ?? _testLibPartContent,
     };
   }
   
  
positive.code:     await testBuilder(
          new PartBuilder([const UnformattedCodeGenerator()],
              formatOutput: (s) => s),
          {'$pkgName|lib/a.dart': 'library a; part "a.part.dart";'},
          generateFor: new Set.from(['$pkgName|lib/a.dart']),
          outputs: {
            '$pkgName|lib/a.g.dart': decodedMatches(
                contains(UnformattedCodeGenerator.unformattedCode)),
          });
    });
  
negative.code:     await testBuilder(
          new PartBuilder([const UnformattedCodeGenerator()],
              header: _customHeader),
          {'$_pkgName|lib/a.dart': 'library a; part "a.part.dart";'},
          generateFor: new Set.from(['$_pkgName|lib/a.dart']),
          outputs: {
            '$_pkgName|lib/a.g.dart':
                decodedMatches(startsWith('$_customHeader\npart of')),
          });
    });
  