def test_starts_in_initial_state(self):
state_machine = StateMachine()
state_a = state_machine.define_initial_state('a')
state_b = state_machine.define_state('b')
state_machine.define_transition(state_a, state_b)
walker = state_machine.start()
self.assertEqual(state_a, walker.get_state())
def test_accepts_move_with_transition(self):
state_machine = StateMachine()
state_a = state_machine.define_initial_state('a')
state_b = state_machine.define_state('b')
state_machine.define_transition(state_a, state_b)
walker = state_machine.start()
self.assertTrue(walker.move_to(state_b))
self.assertEqual(state_b, walker.get_state())
def test_rejects_move_to_self_without_transition(self):
state_machine = StateMachine()
state_a = state_machine.define_initial_state('a')
state_b = state_machine.define_state('b')
state_machine.define_transition(state_a, state_b)
# There is no transition from a to a, so move_to() should return false,
# however we should still be in state a after.
walker = state_machine.start()
self.assertFalse(walker.move_to(state_a))
self.assertEqual(state_a, walker.get_state())
def test_rejects_move_without_transition(self):
state_machine = StateMachine()
state_a = state_machine.define_initial_state('a')
state_b = state_machine.define_state('b')
state_c = state_machine.define_state('c')
state_machine.define_transition(state_a, state_b)
state_machine.define_transition(state_b, state_c)
walker = state_machine.start()
self.assertFalse(walker.move_to(state_c))
self.assertEqual(state_a, walker.get_state())
