我正在關注來自Ray Wenderlich團隊的過時tutorial,該團隊使用命令行工具應用程序遍歷了應用Core Data
-backed應用程序的重新填充。如何使用核心數據模型與內存中的存儲類型使用預填充的SQLite文件?
我已成功預先填充預定實體,並通過執行NSFetchRequest
進行驗證。
現在,我想在我的單元測試中使用相同的預填充數據來驗證我與CoreData
的交互正確發生。我試圖設置我的模擬CoreDataStack
子類使用內存中的存儲,但是當我試圖驗證我有我的單元測試中使用的預填充數據時,我得到0
的count
。
類負責與我的應用程序的目標CoreData
互動,名爲CoreDataStack
,如下:
/// The object that is responsible for managing interactions with Core Data.
internal class CoreDataStack {
// MARK: - Properties
/// The name of the `NSManagedObjectModel` object used for storing information with Core Data.
private let modelName: String
/// The `NSManagedObjectContext` object that is associated with the main queue.
internal lazy var mainContext: NSManagedObjectContext = {
return self.storeContainer.viewContext
}()
/// The `NSPersistentContainer` object that encapsulates the application's Core Data stack.
internal lazy var storeContainer: NSPersistentContainer = {
let container = NSPersistentContainer(name: self.modelName)
let directory = NSPersistentContainer.defaultDirectoryURL()
let storeURL = directory.appendingPathComponent("\(self.modelName).sqlite")
if !FileManager.default.fileExists(atPath: (storeURL.path)) {
guard let populatedURL = Bundle.main.url(forResource: self.modelName, withExtension: "sqlite") else {
fatalError("Invalid populated .sqlite file URL")
}
do {
try FileManager.default.copyItem(at: populatedURL, to: storeURL)
} catch {
fatalError("Error: \(error)")
}
}
let description = NSPersistentStoreDescription()
description.url = storeURL
container.persistentStoreDescriptions = [description]
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError? {
fatalError("Error: \(error)")
}
})
return container
}()
// MARK: - Initialization
/// Returns an instance of `CoreDataStack`.
/// - parameter modelName: The name of the `NSManagedObjectModel` object used for storing information with Core Data.
internal init(modelName: String) {
self.modelName = modelName
}
/// Attempts to save items to Core Data by committing changes to `NSManagedObject`s in a `NSManagedObjectContext`.
/// - parameter context: The `NSManagedObjectContext` of which changes should be committed.
internal func saveContext(_ context: NSManagedObjectContext) {
context.perform {
do {
try context.save()
} catch let error as NSError {
fatalError("Unresolved error \(error), \(error.userInfo)")
}
}
}
}
的CoreDataStack
,MockCoreDataStack
的子類,用於測試如下:
internal class MockCoreDataStack: CoreDataStack {
// MARK: - Initialization
convenience init() {
self.init(modelName: "Currency")
}
override init(modelName: String) {
super.init(modelName: modelName)
let container = NSPersistentContainer(name: modelName)
let directory = NSPersistentContainer.defaultDirectoryURL()
let storeURL = directory.appendingPathComponent("\(modelName).sqlite")
if !FileManager.default.fileExists(atPath: (storeURL.path)) {
guard let populatedURL = Bundle(for: type(of: self)).url(forResource: modelName, withExtension: "sqlite") else {
fatalError("Invalid populated .sqlite file URL")
}
do {
try FileManager.default.copyItem(at: populatedURL, to: storeURL)
} catch {
fatalError("Error: \(error)")
}
}
let description = NSPersistentStoreDescription()
description.url = storeURL
description.type = NSInMemoryStoreType
container.persistentStoreDescriptions = [description]
container.loadPersistentStores { (storeDescription, error) in
if let error = error as NSError? {
fatalError("Unresolved error \(error), \(error.userInfo)")
}
}
self.storeContainer = container
}
}
產生的count
我的提取請求的單元測試目標是0
。我希望返回包含預填充對象數量的count
,就像我在返回應用程序目標中的count
時所得到的一樣。
我做了什麼不正確的事情導致我沒有返回預期的結果?