def test_notify_for_nested_constraint():
events = []
solver = Solver()
a = Variable()
b = Variable()
nested = EqualsConstraint(a, b)
multi = MultiConstraint(nested)
solver.add_constraint(multi)
solver.solve()
def handler(constraint):
events.append(constraint)
solver.add_handler(handler)
a.value = 10
solver.solve()
assert multi in events
assert nested not in events
