from matrixmania.compute import matmul, transpose
import pytest

def test_matmul_basic():
    a = [[1, 2], [3, 4]]
    b = [[2, 0], [1, 2]]
    expected = [[4, 4], [10, 8]]
    assert matmul(a, b) == expected

def test_matmul_invalid_dimensions():
    a = [[1, 2, 3]]
    b = [[1, 2], [3, 4]]
    with pytest.raises(ValueError):
        matmul(a, b)