import numpy as np
from numpy.testing import assert_array_equal
from skimage.measure._sum_blocks import sum_blocks

def test_downsample_sum_blocks():
    """Verifying downsampling of an array with expected result in sum mode"""
    image1 = np.arange(4*6).reshape(4, 6)
    out1 = sum_blocks(image1, (2, 3))
    expected1 = np.array([[ 24,  42],
                          [ 96, 114]])
    assert_array_equal(expected1, out1)
    image2 = np.arange(5*8).reshape(5, 8)
    out2 = sum_blocks(image2, (3, 3))
    expected2 = np.array([[ 81, 108,  87],
                          [174, 192, 138]])
    assert_array_equal(expected2, out2)