def test_convex_hull():
p = [Point(-5, -1), Point(-2, 1), Point(-2, -1), Point(-1, -3),
Point(0, 0), Point(1, 1), Point(2, 2), Point(2, -1), Point(3, 1),
Point(4, -1), Point(6, 2)]
ch = Polygon(p[0], p[3], p[9], p[10], p[6], p[1])
# test handling of duplicate points
p.append(p[3])
# more than 3 collinear points
another_p = [Point(-45, -85), Point(-45, 85), Point(-45, 26),
Point(-45, -24)]
ch2 = Segment(another_p[0], another_p[1])
assert convex_hull(*another_p) == ch2
assert convex_hull(*p) == ch
assert convex_hull(p[0]) == p[0]
assert convex_hull(p[0], p[1]) == Segment(p[0], p[1])
# no unique points
assert convex_hull(*[p[-1]]*3) == p[-1]
# collection of items
assert convex_hull(*[Point(0, 0),
Segment(Point(1, 0), Point(1, 1)),
RegularPolygon(Point(2, 0), 2, 4)]) == \
Polygon(Point(0, 0), Point(2, -2), Point(4, 0), Point(2, 2))
def test_util():
# coverage for some leftover functions in diofant.geometry.util
assert intersection(Point(0, 0)) == []
pytest.raises(ValueError, lambda: intersection(Point(0, 0), 3))
pytest.raises(ValueError, lambda: convex_hull(Point(0, 0), 3))
