@Test
    public void test_loadArrayFromFile() {

        String filePath = "test.txt";

        // creating list with specified amount of random numbers
        List<Integer> list = appUtil.getRandomNumbers(10, 10);
        appUtil.saveArrayToFile(filePath, list);

        // testing content of file
        List<Integer> list2 = appUtil.loadArrayFromFile(filePath);
        assertEquals("Fail - file must contain same digits", list, list2);

        // deleting testing file
        File myFile = new File(filePath);
        if (myFile.exists()) {
            myFile.delete();
        }
    }