def test_extends_prefix_from_right():
def f(chooser):
chooser.choose(range(4))
tree = ChoiceTree()
result = tree.step(select(), f)
assert result == (3,)
def test_skips_over_exhausted_subtree():
def f(chooser):
chooser.choose(range(10))
tree = ChoiceTree()
assert tree.step(select(8), f) == (8,)
assert tree.step(select(8), f) == (7,)
def test_wraps_around_to_beginning():
def f(chooser):
chooser.choose(range(3))
tree = ChoiceTree()
assert tree.step((2, ), f) == ()
def exhaust(f):
tree = ChoiceTree()
results = []
prefix = ()
while not tree.exhausted:
prefix = tree.step(prefix, lambda chooser: results.append(f(chooser)))
return results
def test_exhausts_randomly_when_filtering():
def f(chooser):
chooser.choose(range(10), lambda x: False)
tree = ChoiceTree()
random = Random()
tree.step(random_selection_order(random), f)
assert tree.exhausted
def test_exhausts_randomly():
def f(chooser):
chooser.choose(range(10))
tree = ChoiceTree()
random = Random()
seen = set()
for _ in range(10):
seen.add(tree.step(random_selection_order(random), f))
assert len(seen) == 10
assert tree.exhausted
def test_skips_over_exhausted_children():
results = []
def f(chooser):
results.append((
chooser.choose(range(3), condition=lambda x: x > 0),
chooser.choose(range(2)),
))
tree = ChoiceTree()
tree.step(select(1, 0), f)
tree.step(select(1, 1), f)
tree.step(select(0, 0), f)
assert results == [(1, 0), (1, 1), (2, 0)]
def test_starts_from_the_end():
def f(chooser):
chooser.choose(range(3))
tree = ChoiceTree()
assert tree.step(select(), f) == (2,)
