KVOTests

KVOTest

//
//  KVOTests.swift
//  SwiftStuff
//
//  Created by Venkat Peri on 8/11/14.
//  Copyright (c) 2014 vperi. All rights reserved.
//

import Cocoa
import XCTest

class KVOTests: XCTestCase {
  
  class Publisher : NSObject {
    dynamic var someProperty : Int = 100 { didSet { println("didSet \(someProperty)") } }
    
    override var description: String { return "Publisher:{someProperty: \(someProperty)}" }
  }
  
  class Subscriber : NSObject  {
    var callback: ()->()
    
    init(callback: ()->()) {
      self.callback = callback
    }

    override func observeValueForKeyPath(keyPath: String!, ofObject object: AnyObject!,
      change: [NSObject : AnyObject]!, context: UnsafeMutablePointer<()>) {
        println("Subscriber: observeValueForKey: \(keyPath), \(object)")
        self.callback()
    }
  }
  
  var pub: Publisher!
  var sub: Subscriber!
  
  override func setUp() {
    super.setUp()
    pub = Publisher()
  }
  
  override func tearDown() {
    // Put teardown code here. This method is called after the invocation of each test method in the class.
    super.tearDown()
  }
  
  func testCallbackOnChange() {
    var called = false
    sub = Subscriber(callback: { called = true } )
    pub.addObserver(sub, forKeyPath: "someProperty", options: NSKeyValueObservingOptions.New, context: nil)
    XCTAssert(called == false, "Shouldn't receive initial callback")
    pub.someProperty = 101
    XCTAssert(called, "Should receive callback on new value")
    println("printing pub: \(pub)")
    println("printing pub.description: \(pub.description)")
    pub.removeObserver(sub, forKeyPath: "someProperty")
  }
  
}