from peakrdl_busdecoder.utils import clog2, is_pow2, roundup_pow2


class TestMathUtils:
    """Test mathematical utility functions."""

    def test_clog2_basic(self) -> None:
        """Test clog2 function with basic values."""
        assert clog2(1) == 0
        assert clog2(2) == 1
        assert clog2(3) == 2
        assert clog2(4) == 2
        assert clog2(5) == 3
        assert clog2(8) == 3
        assert clog2(9) == 4
        assert clog2(16) == 4
        assert clog2(17) == 5
        assert clog2(32) == 5
        assert clog2(33) == 6
        assert clog2(64) == 6
        assert clog2(128) == 7
        assert clog2(256) == 8
        assert clog2(1024) == 10

    def test_is_pow2_true_cases(self) -> None:
        """Test is_pow2 returns True for powers of 2."""
        assert is_pow2(1) is True
        assert is_pow2(2) is True
        assert is_pow2(4) is True
        assert is_pow2(8) is True
        assert is_pow2(16) is True
        assert is_pow2(32) is True
        assert is_pow2(64) is True
        assert is_pow2(128) is True
        assert is_pow2(256) is True
        assert is_pow2(512) is True
        assert is_pow2(1024) is True

    def test_is_pow2_false_cases(self) -> None:
        """Test is_pow2 returns False for non-powers of 2."""
        assert is_pow2(0) is False
        assert is_pow2(3) is False
        assert is_pow2(5) is False
        assert is_pow2(6) is False
        assert is_pow2(7) is False
        assert is_pow2(9) is False
        assert is_pow2(10) is False
        assert is_pow2(15) is False
        assert is_pow2(17) is False
        assert is_pow2(100) is False
        assert is_pow2(255) is False
        assert is_pow2(1000) is False

    def test_roundup_pow2_already_power_of_2(self) -> None:
        """Test roundup_pow2 with values that are already powers of 2."""
        assert roundup_pow2(1) == 1
        assert roundup_pow2(2) == 2
        assert roundup_pow2(4) == 4
        assert roundup_pow2(8) == 8
        assert roundup_pow2(16) == 16
        assert roundup_pow2(32) == 32
        assert roundup_pow2(64) == 64
        assert roundup_pow2(128) == 128
        assert roundup_pow2(256) == 256

    def test_roundup_pow2_non_power_of_2(self) -> None:
        """Test roundup_pow2 with values that are not powers of 2."""
        assert roundup_pow2(3) == 4
        assert roundup_pow2(5) == 8
        assert roundup_pow2(6) == 8
        assert roundup_pow2(7) == 8
        assert roundup_pow2(9) == 16
        assert roundup_pow2(15) == 16
        assert roundup_pow2(17) == 32
        assert roundup_pow2(31) == 32
        assert roundup_pow2(33) == 64
        assert roundup_pow2(100) == 128
        assert roundup_pow2(255) == 256
        assert roundup_pow2(257) == 512