import pytest



from const import gray_1d

# Happy path tests with various realistic test values
@pytest.mark.parametrize("k, symbol, expected", [
    (0, 0, 0),  # k=0 case
    (1, 0, 1),  # k=1, symbol=0 case
    (1, 1, -1),  # k=1, symbol=1 case
    (2, 0, 3),  # k=2, symbol=0 case
    (2, 1, 1),  # k=2, symbol=1 case
    (2, 2, -3),  # k=2, symbol=2 case
    (2, 3, -1),  # k=2, symbol=3 case
], ids=[
    "k=0_symbol=0",
    "k=1_symbol=0",
    "k=1_symbol=1",
    "k=2_symbol=0",
    "k=2_symbol=1",
    "k=2_symbol=2",
    "k=2_symbol=3"
])
def test_gray_1d_happy_path(k, symbol, expected):
    # Act
    result = gray_1d(k, symbol)

    # Assert
    assert result == expected

# Various edge cases
@pytest.mark.parametrize("k, symbol, expected", [
    (3, 0, 7),  # k=3, symbol=0 case
    (3, 7, -3),  # k=3, symbol=7 case
    (4, 0, 15),  # k=4, symbol=0 case
    (4, 15, -5),  # k=4, symbol=15 case
], ids=[
    "k=3_symbol=0",
    "k=3_symbol=7",
    "k=4_symbol=0",
    "k=4_symbol=15"
])
def test_gray_1d_edge_cases(k, symbol, expected):
    # Act
    result = gray_1d(k, symbol)

    # Assert
    assert result == expected

# Various error cases
@pytest.mark.parametrize("k, symbol, exception", [
    (-1, 0, ValueError),  # k is negative
    (1, -1, ValueError),  # symbol is negative
    (1, 2, ValueError),  # symbol is out of range for k=1
    (2, 4, ValueError),  # symbol is out of range for k=2
], ids=[
    "k_negative",
    "symbol_negative",
    "symbol_out_of_range_k1",
    "symbol_out_of_range_k2"
])
def test_gray_1d_error_cases(k, symbol, exception):
    # Act and Assert
    with pytest.raises(exception):
        gray_1d(k, symbol)