accessing app delegate object in XCTestCase class causes misaligned_stack_error_ swift

Question

I am trying to perform unit testing in swift.

I defined my test case class like this:

import XCTest
import CoreData
import UIKit

class LazyLoadingCheckTests: XCTestCase {

    var appDelegate : AppDelegate = UIApplication.sharedApplication().delegate as AppDelegate

    override func setUp() {
        super.setUp()
        // Put setup code here. This method is called before the invocation of each test method in the class.
    }

    override func tearDown() {
        // Put teardown code here. This method is called after the invocation of each test method in the class.
        super.tearDown()
    }

    func testExample() {
        // This is an example of a functional test case.
        XCTAssert(true, "Pass")
    }
}

Whenever I am trying to execute a test case, the breakpoint is automatically stopping at below line:

It shows below stack trace:

When I try to continue it shows this:

Any clues?