def test_most_popular_item():
    my_problem = NearestNeighborsOpt(schema)
    result = my_problem.get_most_pop_item()
    expected = np.array([3, 1, 5, 1, 1, 4, 3, 5])
    np.testing.assert_array_equal(result, expected, "Fail : most_popular_item")