anchor.diff:        d
             .dir('pkg', [
           d.dir('lib', [
  -          d.file('person.dart', _personContent),
  -          d.matcherFile('person.g.dart', isNotEmpty)
  +          d.file('person.dart', _testLibContent),
  +          d.matcherFile('person.g.dart', contains(_testGenPartContent))
           ])
         ])
             .validate();
  
positive.code: import 'dart:async';
  import 'dart:io';
  
  import 'package:scheduled_test/descriptor.dart' as d;
  import 'package:scheduled_test/scheduled_test.dart';
  import 'package:path/path.dart' as p;
  
  import 'package:source_gen/src/build_file_generator.dart';
  import 'package:source_gen/json_serial/json_generator.dart';
  
  import 'test_utils.dart';
  
  void main() {
    test('Simple test of JsonGenerator', () {
      String projectPath;
  
      schedule(() async {
  
negative.code: /// Creates a package using [pkgName] an the current [d.defaultRoot].
  Future<String> _createPackageStub(String pkgName) async {
    await d
        .dir(pkgName, [d.dir('lib', [d.file('person.dart', _testLibContent)])])
        .create();
  
    var pkgPath = p.join(d.defaultRoot, pkgName);
  