from peak.events import trellis


class TestOrder(trellis.Component):
   trellis.compute.attrs(
       rule_a = lambda self: [self.rule_b, 'a'],
       rule_b = lambda self: [self.rule_a, 'b']
   )

TestOrder().rule_a  # [[None, 'b'], 'a']
# should throw CircularityError




class TestInsonsistentInit(trellis.Component):
   trellis.attrs(v1=False, v2=True)

   @trellis.maintain(optional=True)
   def rule_a(self):
       self.v2 = False

   @trellis.maintain
   def rule_b(self):
      if self.v1 and self.v2:
          self.rule_a
          return True

tc = TestInsonsistentInit()
tc.v1 = True
#print tc.v2, tc.rule_b # False, True
assert not tc.v2
assert not tc.rule_b