def test_submatrix_of_4_by_4_matrix_is_3_by_3_matrix(self):
matrix = Matrix([[-6, 1, 1, 6], [-8, 5, 8, 6], [-1, 0, 8, 2],
[-7, 1, -1, 1]])
result = matrix.submatrix(2, 1)
assert result == Matrix([[-6, 1, 6], [-8, 8, 6], [-7, -1, 1]])
def test_caclculating_minor_of_3_by_3_matrix(self):
matrix = Matrix([[3, 5, 0], [2, -1, -7], [6, -1, 5]])
sub_matrix = matrix.submatrix(1, 0)
determinant = sub_matrix.determinant()
minor = matrix.minor(1, 0)
assert determinant == 25
assert determinant == minor
def test_submatrix_of_3_by_3_is_2_by_2_matrix(self):
matrix = Matrix([[1, 5, 0], [-3, 2, 7], [0, 6, -3]])
result = matrix.submatrix(0, 2)
assert result == Matrix([[-3, 2], [0, 6]])