def test_add_trail_atts():
hp = Heap()
a = hp.new_attvar()
assert a.created_after_choice_point is hp
assert hp.trail_attrs is None
ma = AttMap()
ma.indexes = {"a": 0}
a.value_list = [10]
a.attmap = ma
hp.add_trail_atts(a, "a")
assert hp.trail_attrs is None
hp2 = hp.branch()
hp2.add_trail_atts(a, "a")
assert hp2.trail_attrs == [(a, 0, 10)]
a.add_attribute("a", 20)
assert a.value_list == [20]
hp2._revert()
assert a.value_list == [10]
hp3 = hp2.branch()
hp3.add_trail_atts(a, "b")
a.add_attribute("b", 30)
assert a.value_list == [10, 30]
assert a.attmap.indexes == {"a": 0, "b": 1}
assert a.attmap is not ma
hp3._revert()
assert a.value_list == [10, None]
def test_heap_dont_trail_new_attvars():
h1 = Heap()
v1 = h1.new_attvar()
h1.add_trail_atts(v1, "m")
v1.add_attribute("m", 1)
h2 = h1.branch()
v2 = h2.new_attvar()
h2.add_trail_atts(v1, "m")
v1.add_attribute("m", 2)
h2.add_trail_atts(v2, "m")
v2.add_attribute("m", 3)
h3 = h2.revert_upto(h1)
t1 = v1.get_attribute("m")
assert t1[0] == 1
assert t1[1] == 0
t2 = v2.get_attribute("m") # wasn't undone, because v2 dies
assert t2[0] == 3
assert t2[1] == 0
assert h3 is h2