def test_extract_block():
eq_(sudoku.extract_block([[1] + [0] * 8] * 9, 0, 0), [1, 0, 0] * 3)
eq_(sudoku.extract_block([[0, 1, 0, 0, 0, 0, 0, 0, 0],
[0] * 9, [0] * 9, [0] * 9, [0] * 9, [0] * 9, [0] * 9, [0] * 9, [0] * 9], 0, 0),
[0, 1, 0, 0, 0, 0, 0, 0, 0])
eq_(sudoku.extract_block([[0, 0, 0, 0, 0, 0, 0, 0, 1],
[0] * 9, [0] * 9, [0] * 9, [0] * 9, [0] * 9, [0] * 9, [0] * 9, [0] * 9], 7, 0),
[0, 0, 1, 0, 0, 0, 0, 0, 0])
def valid_block(board, x, y):
return valid_seq(sudoku.extract_block(board, x, y))
