def test_nearest_colour():
"""
Find the nearest available colour
"""
from painterm.colour import Colour, nearest_colour
# empty palette
assert_is_none(nearest_colour(Colour(0, 0, 0, 0), []))
assert_equals(nearest_colour(Colour(64, 64, 64, 1.0), [Colour(0, 0, 0, 1.0), Colour(255, 255, 255, 1.0)]), 0)
assert_equals(nearest_colour(Colour(64, 64, 64, 1.0), [Colour(255, 255, 255, 1.0), Colour(0, 0, 0, 1.0)]), 1)
assert_equals(nearest_colour(Colour(64, 64, 64, 1.0), [Colour(64, 64, 0, 1.0), Colour(64, 0, 64, 1.0)]), 0)
assert_equals(nearest_colour(Colour(64, 64, 64, 1.0), [Colour(64, 64, 0, 1.0), Colour(64, 64, 64, 1.0)]), 1)
def translate(self, colour):
"""
Translate a colour into an ansi escape code.
"""
if colour not in self._cache:
ansi = nearest_colour(colour, self._palette)
self._cache[colour] = ansi
return self._cache[colour]