@Test
    public void test_allFunctionality() {

        File file = new File(filePath);

        if (file.exists()) {
            for (SortingAlgorithm algorithm: algorithmList) {

                // loading list from file and asserting target list
                List<Integer> unsortedListFormFile = appUtil.loadArrayFromFile(filePath);
                assertEquals("FAIL - list size must be same,", randomNumbersList, unsortedListFormFile);

                // sorting list and asserting for equal value
                List<Integer> sortedListFromFile = algorithm.sort(unsortedListFormFile);
                assertEquals("FAIL - list must contain same digits,", sortedList, sortedListFromFile);

                // saving testedList to new file
                appUtil.saveArrayToFile(sortedFilePath, sortedListFromFile);

                // asserting new file
                File testedFile = new File(sortedFilePath);
                assertTrue("Fail - file test.text must be created", testedFile.exists());

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

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