anchor.diff:  @TestOn('vm')
   import 'dart:async';
  +import 'dart:isolate';
   
   import 'package:moor/isolate.dart';
   import 'package:moor/moor.dart';
  
positive.code: DatabaseConnection _backgroundConnection() {
    return DatabaseConnection.fromExecutor(VmDatabase.memory());
  }
  
negative.code:     }
  
      _runTests(spawnBackground, true);
    });
  
    test('stream queries across isolates', () async {
      // three isolates:
      // 1. this one, starting a query stream
      // 2. another one running an insert
      // 3. the MoorIsolate executor the other two are connecting to
      final moorIsolate = await MoorIsolate.spawn(_backgroundConnection);
  
      final receiveDone = ReceivePort();
      final writer = await Isolate.spawn(_writeTodoEntryInBackground,
          _BackgroundEntryMessage(moorIsolate, receiveDone.sendPort));
  
      final db = TodoDb.connect(await moorIsolate.connect());
      final expectedEntry = const TypeMatcher<TodoEntry>()
          .having((e) => e.content, 'content', 'Hello from background');
  
      final expectation = expectLater(
        db.select(db.todosTable).watch(),
        // can optionally emit an empty list if this isolate connected before the
        // other one.
        emitsInOrder([
          mayEmit([]),
          [expectedEntry]
        ]),
      );
  
      await receiveDone.first;
      writer.kill();
      await expectation;
    });
  }
  
  