 
 class StackViewControllerDemoTests: XCTestCase {
     
-    let obviously = "test case very simple, no need to provide extra info"
-    
     let a = UIViewController()
     let b = UIViewController()
     let c = UIViewController()

        stack.viewControllers = [a, b, c, d, e, f]
        
        var poppedViewController = stack.popViewControllerAnimated(false)
        XCTAssert(stack.viewControllers == [a, b, c, d, e], obviously)
        XCTAssert(poppedViewController == f, obviously)
        
        var poppedViewControllers = stack.popToViewController(c, animated: false)
        XCTAssert(stack.viewControllers == [a, b, c], obviously)
        XCTAssert(poppedViewControllers == [d, e], obviously)
        
        poppedViewControllers = stack.popToRootViewControllerAnimated(false)
        XCTAssert(stack.viewControllers == [a], obviously)
        XCTAssert(poppedViewControllers == [b, c], obviously)
        
        poppedViewController = stack.popViewControllerAnimated(false)
        XCTAssert(stack.viewControllers == [a], obviously)
        XCTAssertNil(poppedViewController, obviously)
    }
    
    func testSetViewControllers() {

        let stack = StackViewController()
        stack.viewControllers = [a, b, c]
        stack.viewControllers = [b, e]
        XCTAssert(stack.viewControllers.count == 2)
        XCTAssert(stack.viewControllers == [b, e])
        
        stack.pushViewController(c, animated: false)
        XCTAssert(stack.viewControllers == [b, e, c])
        
        stack.setViewControllers([f, e, c], animated: false)
        XCTAssert(stack.viewControllers == [f, e, c])
    }
    
    func testChildViewControllers() {
        let stack = StackViewController()
        stack.viewControllers = [a, b, c]
        XCTAssert(stack.childViewControllers.count == 3)
        XCTAssert(stack.childViewControllers.last == c)
        
        stack.setViewControllers([d, e], animated: false)
        XCTAssert(stack.childViewControllers.count == 2)
        XCTAssert(stack.childViewControllers.last == e)
        
        stack.pushViewController(f, animated: false)
        XCTAssert(stack.childViewControllers.count == 3)
        XCTAssert(stack.childViewControllers.last == f)
        
        stack.popViewControllerAnimated(false)
        XCTAssert(stack.childViewControllers.count == 2)
        XCTAssert(stack.childViewControllers.last == e)
        
        stack.popToRootViewControllerAnimated(false)
        XCTAssert(stack.childViewControllers.count == 1)
        XCTAssert(stack.childViewControllers.last == d)
                
        stack.viewControllers = [a, b, c, d]
        stack.viewControllers = [e, f, a]
        XCTAssert(stack.childViewControllers.count == 3)
        
        // those are expected since we cannot reorder childViewControllers
        
        XCTAssert(stack.childViewControllers == [a, e, f])
        
        stack.viewControllers = [a, b, c, d]
        stack.setViewControllers([d, a, c], animated: false)
        
        XCTAssert(stack.childViewControllers == [a, c, d])
        
        stack.viewControllers = []
        XCTAssert(stack.childViewControllers.isEmpty)
    }
    
    func testUIViewControllerExtension() {
