def test_sobel_zeros():
 result = filters.sobel(np.zeros((10, 10)), np.ones((10, 10), bool))
 assert np.all((result == 0))

def test_sobel_zeros ( ) : result = filters . sobel ( np . zeros ( ( 10 , 10 ) ) , np . ones ( ( 10 , 10 ) , bool ) ) assert np . all ( ( result == 0 ) )
sobel on an array of all zeros .