    @Test
    @UseDataProvider("selectTopKData")
    public void selectTopKShouldReturnAValidOutput(int k, AdsOptimizationImpl expected) {

        System.out.println("selectTopKShouldReturnAValidOutput");
        // to do, for candidateAds size > k + 1 and <= k+1
        assertEquals(expected, ads.selectTopK(k));
    }