 
     func testQueueInNormalModelAfterSwitchingIfFromRepeatMode() {
         let queue = AudioItemQueue(items: [item1, item2, item3], mode: .repeat)
-        _ = try! queue.nextItem()
+        XCTAssertNotNil(try! queue.nextItem())
 
         queue.mode = .normal
         XCTAssert((try! queue.nextItem()) === item2)
 
         let queue2 = AudioItemQueue(items: [item1], mode: .repeat)
-        _ = try! queue2.nextItem()
+        XCTAssertNotNil(try! queue2.nextItem())
 
         queue2.mode = .normal
         XCTAssert((try! queue2.nextItem()) === nil)

        XCTAssertFalse(queue.hasPreviousItem)
        XCTAssertNil(try! queue.previousItem())

        _ = try! queue.nextItem()
        XCTAssert(queue.hasNextItem)
        XCTAssert((try! queue.previousItem()) === item1)
    }

    func testHasNextItemInQueue() {
        let queue = AudioItemQueue(items: [item1, item2, item3], mode: [.normal])
        XCTAssert(queue.hasNextItem)
        XCTAssertNotNil(try! queue.nextItem())
        XCTAssert(queue.hasNextItem)
        XCTAssertNotNil(try! queue.nextItem())
        XCTAssert(queue.hasNextItem)
        XCTAssertNotNil(try! queue.nextItem())
        XCTAssertFalse(queue.hasNextItem)

        queue.mode = .repeat
        for _ in 0...100 {
            XCTAssertNotNil(try! queue.nextItem())
            XCTAssert(queue.hasNextItem)
        }

        queue.mode = .repeatAll
        for _ in 0...100 {
            XCTAssertNotNil(try! queue.nextItem())
            XCTAssert(queue.hasNextItem)
        }

