'Check if adding of two 1D kernels works.'

def test_add_2D_kernels(self):

    box_1 = Box2DKernel(3)
    box_2 = Box2DKernel(1)
    box_sum_1 = (box_1 + box_2)
    box_sum_2 = (box_2 + box_1)
    ref = [[(1 / 9.0), (1 / 9.0), (1 / 9.0)], [(1 / 9.0), (1 + (1 / 9.0)), (1 / 9.0)], [(1 / 9.0), (1 / 9.0), (1 / 9.0)]]
    ref_1 = [[(1 / 9.0), (1 / 9.0), (1 / 9.0)], [(1 / 9.0), (1 / 9.0), (1 / 9.0)], [(1 / 9.0), (1 / 9.0), (1 / 9.0)]]
    assert_almost_equal(box_2.array, [[1]], decimal=12)
    assert_almost_equal(box_1.array, ref_1, decimal=12)
    assert_almost_equal(box_sum_1.array, ref, decimal=12)
    assert_almost_equal(box_sum_2.array, ref, decimal=12)
