def test_xor_pixel_sets_correct_values(self):
"""Xoring a pixel draws correctly for both on and off pixels """
v = VideoRam(3, 5)
v.xor_pixel(2, 4, True)
assert v.pixels[14]
v.xor_pixel(2, 4, True)
assert not v.pixels[14]
def test_wrapping_when_set(self):
"""Coordinates exceeding dimensions wrap when wrapping is on"""
v = VideoRam(2, 2, wrap=True)
assert v.wrap
assert not v.xor_pixel(2, 2, True)
assert v[0, 0]
assert not v[1, 0]
assert not v[0, 1]
assert not v[1, 1]
def test_wrapping_unset(self):
"""Coordinates exceeding dimensions don't wrap if wrapping is off"""
v = VideoRam(1, 1)
assert not v.xor_pixel(1, 1, True)
assert not v[0, 0]
def test_xor_pixel_signals_switchoffs(self):
"""Xoring a pixel returns correct switch-off signals"""
v = VideoRam(2, 4)
assert not v.xor_pixel(1, 3, True)
assert v.xor_pixel(1, 3, True)