from tools.check_vram import vram_to_logical


def test_vram_downsamples_2x2_lsb_first():
    # VRAM bit 1 is white, bit 0 is black (the driver's palette).
    vram = bytearray(256 * 1024)
    vram[0] = 0x0C          # bits 2 and 3 white in row 0
    vram[256] = 0x0C        # bits 2 and 3 white in row 1
    logical = vram_to_logical(bytes(vram), width=640, height=512, scale=2)
    assert logical[0, 0]        # bits 0..1 are black
    assert not logical[0, 1]    # bits 2..3 are white