"Bad state: This database has already been closed" error in unit-tests

[rubiktubik]

Hello, I followed the guide to setup my unit-test with moor.

When i have one unit-test everything runs fine, but with one additional test i get the

Bad state: This database has already been closed

error.

My database-class:

class MyDatabase extends _$MyDatabase {
  // we tell the database where to store the data with this constructor
  MyDatabase(QueryExecutor e) : super(e);
...

My test setup:

late MyDatabase _database;
late DbDataProvider _dataProvider;

  setUp(() {
    _database = MyDatabase(VmDatabase.memory());
    _dataProvider = DbDataProvider(_database);
  });

  tearDown(() async {
    await _database.close();
  });

My tests:

test('can create workout in db', () async {
    // Arrange
    Execution execution = Execution(currentRepetitons: 9, started: true);
    Execution execution2 = Execution(currentRepetitons: 8, started: true);
    Execution execution3 = Execution(currentRepetitons: 7, started: true);
    Exercise exercise = Exercise(
        name: 'Squat',
        minRepetitions: 5,
        maxRepetitions: 9,
        executions: [execution, execution2, execution3],
        weigth: 35);
    Workout workout = Workout(
        day: DateTime.now(),
        exercises: [exercise],
        completed: true,
        dayCount: 1);

    // Act
    _dataProvider.saveWorkout(workout);
    final exercises = await _dataProvider.getExercises();
    final sets = await _dataProvider.getSets();

    // Assert
    expect(exercises.isNotEmpty, true);
    expect(exercises[0].name, exercise.name);
    expect(exercises[0].weight, exercise.weigth);

    expect(sets.length, 3);
    expect(sets[0].repetitions, 9);
    expect(sets[1].repetitions, 8);
    expect(sets[2].repetitions, 7);

    expect(sets.length, 3);
    expect(sets[0].repetitions, 9);
    expect(sets[1].repetitions, 8);
    expect(sets[2].repetitions, 7);
  });

  test('successfully convert db data to domain data', () async {
    // Arrange
    Execution execution = Execution(currentRepetitons: 9, started: true);
    Execution execution2 = Execution(currentRepetitons: 8, started: true);
    Execution execution3 = Execution(currentRepetitons: 7, started: true);
    Exercise exercise = Exercise(
        name: 'Squat',
        minRepetitions: 5,
        maxRepetitions: 9,
        executions: [execution, execution2, execution3],
        weigth: 35);
    Workout workoutInDb = Workout(
        day: DateTime.now(),
        exercises: [exercise],
        completed: true,
        dayCount: 1);

    _dataProvider.saveWorkout(workoutInDb);

    // Act

    final workout = await _dataProvider.getWorkoutByDate(workoutInDb.day);

    // Assert
    await expectLater(workout.day.day, workoutInDb.day.day);
  });

The only workaround which fixed the Bad state issue was to remove the tearDown-function. But then i get the

It looks like you've created the database class MyDatabase multiple times

warning.

I'am doing something wrong? Or is the official documentation outdated?

[simolus3]

Opening the database in setUp and closing it in tearDown should work. I'm using the same approach for tests in this package, and it's working fine:

https://github.com/simolus3/moor/blob/a16b34c8d06c919dcd175a399c11b8c48da34bce/moor/test/integration_tests/moor_files_integration_test.dart#L10-L18

My best guess is that you're somehow still using the old database in the second test? Are you storing the database in a top-level or static field somehow? Your test code looks reasonable though.

But also, shouldn't saveWorkout return a future and be awaited in your test? If you're not awaiting everything, it may be that the test completes before saveWorkout is done. In that case the database may be closed prematurely.

[rubiktubik]

awaiting saveWorkout did solve the problem! How could I have missed it 🤦‍♂️😅

Thanks for your time!
It's always a please working with moor 👌

[simolus3]

Thanks for the kind words :) Btw, you can catch this easier by enabling unawaited_futures.