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

        for _ in 0..<10 {
            let viewController = UIViewController()
            viewControllers.append(viewController)
            XCTAssert(viewController.stackViewController == nil, obviously)
        }
        
        let stack = StackViewController()
        
        stack.viewControllers = viewControllers
        for viewController in viewControllers {
            XCTAssertNotNil(viewController.stackViewController, obviously)
            XCTAssert(viewController.stackViewController! == stack, obviously)
        }
        
        stack.popViewControllerAnimated(false)
        XCTAssertNil(viewControllers.last!.stackViewController, obviously)
        
        stack.viewControllers = []
        for viewController in viewControllers {
            XCTAssertNil(viewController.stackViewController, obviously)
        }
    }
    


class StackViewControllerDemoTests: XCTestCase {
    
    let a = UIViewController()
    let b = UIViewController()
    let c = UIViewController()
