Swift NSUserDefaults InMemory for Testing

InMemoryUserDefaults.swift

import Foundation

final class InMemoryUserDefaults: NSUserDefaults {

    static let SuiteName = "InMemory"

    private var data: [String: AnyObject?]

    override init?(suiteName suitename: String?) {
        data = [:]
        super.init(suiteName: InMemoryUserDefaults.SuiteName)
    }

    // MARK: NOP

    override func synchronize() -> Bool {
        return true
    }

    // MARK: get

    override func objectForKey(defaultName: String) -> AnyObject? {
        return data[defaultName] ?? nil
    }

    override func valueForKey(key: String) -> AnyObject? {
        return data[key] ?? nil
    }

    override func stringForKey(defaultName: String) -> String? {
        return data[defaultName] as? String
    }

    override func arrayForKey(defaultName: String) -> [AnyObject]? {
        return data[defaultName] as? [AnyObject]
    }

    override func dictionaryForKey(defaultName: String) -> [String : AnyObject]? {
        return data[defaultName] as? [String : AnyObject]
    }

    override func dataForKey(defaultName: String) -> NSData? {
        return data[defaultName] as? NSData
    }

    override func stringArrayForKey(defaultName: String) -> [String]? {
        return data[defaultName] as? [String]
    }

    override func integerForKey(defaultName: String) -> Int {
        return data[defaultName] as? Int ?? 0
    }

    override func floatForKey(defaultName: String) -> Float {
        return data[defaultName] as? Float ?? 0.0
    }

    override func doubleForKey(defaultName: String) -> Double {
        return data[defaultName] as? Double ?? 0.0
    }

    override func boolForKey(defaultName: String) -> Bool {
        return data[defaultName] as? Bool ?? false
    }

    override func URLForKey(defaultName: String) -> NSURL? {
        return data[defaultName] as? NSURL
    }

    // MARK: set

    override func setObject(value: AnyObject?, forKey defaultName: String) {
        data[defaultName] = value
    }

    override func setValue(value: AnyObject?, forKey key: String) {
        data[key] = value
    }

    override func setInteger(value: Int, forKey defaultName: String) {
        data[defaultName] = value
    }

    override func setDouble(value: Double, forKey defaultName: String) {
        data[defaultName] = value
    }

    override func setFloat(value: Float, forKey defaultName: String) {
        data[defaultName] = value
    }

    override func setBool(value: Bool, forKey defaultName: String) {
        data[defaultName] = value
    }

    override func setURL(url: NSURL?, forKey defaultName: String) {
        data[defaultName] = url
    }
}

// MARK: - NSUserDefaults

extension NSUserDefaults {

    @objc class func transientDefaults() -> InMemoryUserDefaults {
        return InMemoryUserDefaults(suiteName: InMemoryUserDefaults.SuiteName)!
    }
}

/// execute

class Animal: NSObject { let name: String; init(name: String) { self.name = name } }

let us = InMemoryUserDefaults(suiteName: "InMemory")!
us.setObject(Animal(name: "cat"), forKey: "animal")
us.setBool(true, forKey: "lauch")
print(us.objectForKey("animal")?.name) // Optional("cat")
print(us.boolForKey("lauch")) // true