 
 class CoreDataMigrationsTests: XCTestCase {
   // MARK: - LightWeight Migration
-  
+
   /// Creates a .sqlite with some data for the initial model (version 1)
   func createSampleVersion1(completion: @escaping (Result<URL,Error>) -> Void) {
     let containerSQLite = NSPersistentContainer(name: "SampleModel-\(UUID())", managedObjectModel: model)

      completion = progress.fractionCompleted
      completionSteps += 1
    }
    
    try CoreDataMigration.migrateStore(at: sourceURL, targetVersion: targetVersion, enableWALCheckpoint: true, progress: progress)
    let migratedContext = NSManagedObjectContext(model: targetVersion.managedObjectModel(), storeURL: sourceURL)
    let luxuryCars = try LuxuryCar.fetch(in: migratedContext)
    XCTAssertEqual(luxuryCars.count, 5)
    
    let cars = try migratedContext.fetch(NSFetchRequest<NSManagedObject>(entityName: "Car"))
    XCTAssertTrue(cars.count >= 1)
    
    if #available(iOS 11, tvOS 11, watchOS 4, macOS 10.13, *) {
      cars.forEach { car in
        if car is LuxuryCar || car is SportCar {

      }
    }
  }

  func testMigrationFromNotExistingPersistentStore() {
    let url = URL(fileURLWithPath: "/path/to/nothing.sqlite")
    XCTAssertThrowsError(try CoreDataMigration.migrateStore(at: url, targetVersion: SampleModelVersion.version2), "The store shouldn't exist.") { (error) in
