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|
from sqlalchemy import exc as sa_exc
from sqlalchemy.orm import state_changes
from sqlalchemy.testing import eq_
from sqlalchemy.testing import expect_raises_message
from sqlalchemy.testing import fixtures
class StateTestChange(state_changes._StateChangeState):
a = 1
b = 2
c = 3
class StateMachineTest(fixtures.TestBase):
def test_single_change(self):
"""test single method that declares and invokes a state change"""
_NO_CHANGE = state_changes._StateChangeStates.NO_CHANGE
class Machine(state_changes._StateChange):
@state_changes._StateChange.declare_states(
(StateTestChange.a, _NO_CHANGE), StateTestChange.b
)
def move_to_b(self):
self._state = StateTestChange.b
m = Machine()
eq_(m._state, _NO_CHANGE)
m.move_to_b()
eq_(m._state, StateTestChange.b)
def test_single_incorrect_change(self):
"""test single method that declares a state change but changes to the
wrong state."""
_NO_CHANGE = state_changes._StateChangeStates.NO_CHANGE
class Machine(state_changes._StateChange):
@state_changes._StateChange.declare_states(
(StateTestChange.a, _NO_CHANGE), StateTestChange.b
)
def move_to_b(self):
self._state = StateTestChange.c
m = Machine()
eq_(m._state, _NO_CHANGE)
with expect_raises_message(
sa_exc.IllegalStateChangeError,
r"Method 'move_to_b\(\)' "
r"caused an unexpected state change to <StateTestChange.c: 3>",
):
m.move_to_b()
def test_single_failed_to_change(self):
"""test single method that declares a state change but didn't do
the change."""
_NO_CHANGE = state_changes._StateChangeStates.NO_CHANGE
class Machine(state_changes._StateChange):
@state_changes._StateChange.declare_states(
(StateTestChange.a, _NO_CHANGE), StateTestChange.b
)
def move_to_b(self):
pass
m = Machine()
eq_(m._state, _NO_CHANGE)
with expect_raises_message(
sa_exc.IllegalStateChangeError,
r"Method 'move_to_b\(\)' failed to change state "
"to <StateTestChange.b: 2> as "
"expected",
):
m.move_to_b()
def test_change_from_sub_method_with_declaration(self):
"""test successful state change by one method calling another that
does the change.
"""
_NO_CHANGE = state_changes._StateChangeStates.NO_CHANGE
class Machine(state_changes._StateChange):
@state_changes._StateChange.declare_states(
(StateTestChange.a, _NO_CHANGE), StateTestChange.b
)
def _inner_move_to_b(self):
self._state = StateTestChange.b
@state_changes._StateChange.declare_states(
(StateTestChange.a, _NO_CHANGE), StateTestChange.b
)
def move_to_b(self):
with self._expect_state(StateTestChange.b):
self._inner_move_to_b()
m = Machine()
eq_(m._state, _NO_CHANGE)
m.move_to_b()
eq_(m._state, StateTestChange.b)
def test_method_and_sub_method_no_change(self):
"""test methods that declare the state should not change"""
_NO_CHANGE = state_changes._StateChangeStates.NO_CHANGE
class Machine(state_changes._StateChange):
@state_changes._StateChange.declare_states(
(StateTestChange.a,), _NO_CHANGE
)
def _inner_do_nothing(self):
pass
@state_changes._StateChange.declare_states(
(StateTestChange.a,), _NO_CHANGE
)
def do_nothing(self):
self._inner_do_nothing()
m = Machine()
eq_(m._state, _NO_CHANGE)
m._state = StateTestChange.a
m.do_nothing()
eq_(m._state, StateTestChange.a)
def test_method_w_no_change_illegal_inner_change(self):
_NO_CHANGE = state_changes._StateChangeStates.NO_CHANGE
class Machine(state_changes._StateChange):
@state_changes._StateChange.declare_states(
(StateTestChange.a, _NO_CHANGE), StateTestChange.c
)
def _inner_move_to_c(self):
self._state = StateTestChange.c
@state_changes._StateChange.declare_states(
(StateTestChange.a,), _NO_CHANGE
)
def do_nothing(self):
self._inner_move_to_c()
m = Machine()
eq_(m._state, _NO_CHANGE)
m._state = StateTestChange.a
with expect_raises_message(
sa_exc.IllegalStateChangeError,
r"Method '_inner_move_to_c\(\)' can't be called here; "
r"method 'do_nothing\(\)' is already in progress and this "
r"would cause an unexpected state change to "
"<StateTestChange.c: 3>",
):
m.do_nothing()
eq_(m._state, StateTestChange.a)
def test_change_from_method_sub_w_no_change(self):
"""test methods that declare the state should not change"""
_NO_CHANGE = state_changes._StateChangeStates.NO_CHANGE
class Machine(state_changes._StateChange):
@state_changes._StateChange.declare_states(
(StateTestChange.a,), _NO_CHANGE
)
def _inner_do_nothing(self):
pass
@state_changes._StateChange.declare_states(
(StateTestChange.a,), StateTestChange.b
)
def move_to_b(self):
self._inner_do_nothing()
self._state = StateTestChange.b
m = Machine()
eq_(m._state, _NO_CHANGE)
m._state = StateTestChange.a
m.move_to_b()
eq_(m._state, StateTestChange.b)
def test_invalid_change_from_declared_sub_method_with_declaration(self):
"""A method uses _expect_state() to call a sub-method, which must
declare that state as its destination if no exceptions are raised.
"""
_NO_CHANGE = state_changes._StateChangeStates.NO_CHANGE
class Machine(state_changes._StateChange):
# method declares StateTestChange.c so can't be called under
# expect_state(StateTestChange.b)
@state_changes._StateChange.declare_states(
(StateTestChange.a, _NO_CHANGE), StateTestChange.c
)
def _inner_move_to_c(self):
self._state = StateTestChange.c
@state_changes._StateChange.declare_states(
(StateTestChange.a, _NO_CHANGE), StateTestChange.b
)
def move_to_b(self):
with self._expect_state(StateTestChange.b):
self._inner_move_to_c()
m = Machine()
eq_(m._state, _NO_CHANGE)
with expect_raises_message(
sa_exc.IllegalStateChangeError,
r"Cant run operation '_inner_move_to_c\(\)' here; will move "
r"to state <StateTestChange.c: 3> where we are "
"expecting <StateTestChange.b: 2>",
):
m.move_to_b()
def test_invalid_change_from_invalid_sub_method_with_declaration(self):
"""A method uses _expect_state() to call a sub-method, which must
declare that state as its destination if no exceptions are raised.
Test an error is raised if the sub-method doesn't change to the
correct state.
"""
_NO_CHANGE = state_changes._StateChangeStates.NO_CHANGE
class Machine(state_changes._StateChange):
# method declares StateTestChange.b, but is doing the wrong
# change, so should fail under expect_state(StateTestChange.b)
@state_changes._StateChange.declare_states(
(StateTestChange.a, _NO_CHANGE), StateTestChange.b
)
def _inner_move_to_c(self):
self._state = StateTestChange.c
@state_changes._StateChange.declare_states(
(StateTestChange.a, _NO_CHANGE), StateTestChange.b
)
def move_to_b(self):
with self._expect_state(StateTestChange.b):
self._inner_move_to_c()
m = Machine()
eq_(m._state, _NO_CHANGE)
with expect_raises_message(
sa_exc.IllegalStateChangeError,
r"While method 'move_to_b\(\)' was running, method "
r"'_inner_move_to_c\(\)' caused an unexpected state change "
"to <StateTestChange.c: 3>",
):
m.move_to_b()
def test_invalid_prereq_state(self):
_NO_CHANGE = state_changes._StateChangeStates.NO_CHANGE
class Machine(state_changes._StateChange):
@state_changes._StateChange.declare_states(
(StateTestChange.a, _NO_CHANGE), StateTestChange.b
)
def move_to_b(self):
self._state = StateTestChange.b
@state_changes._StateChange.declare_states(
(StateTestChange.c,), "d"
)
def move_to_d(self):
self._state = "d"
m = Machine()
eq_(m._state, _NO_CHANGE)
m.move_to_b()
eq_(m._state, StateTestChange.b)
with expect_raises_message(
sa_exc.IllegalStateChangeError,
r"Can't run operation 'move_to_d\(\)' when "
"Session is in state <StateTestChange.b: 2>",
):
m.move_to_d()
def test_declare_only(self):
_NO_CHANGE = state_changes._StateChangeStates.NO_CHANGE
class Machine(state_changes._StateChange):
@state_changes._StateChange.declare_states(
state_changes._StateChangeStates.ANY, StateTestChange.b
)
def _inner_move_to_b(self):
self._state = StateTestChange.b
def move_to_b(self):
with self._expect_state(StateTestChange.b):
self._move_to_b()
m = Machine()
eq_(m._state, _NO_CHANGE)
with expect_raises_message(
AssertionError,
"Unexpected call to _expect_state outside of "
"state-changing method",
):
m.move_to_b()
def test_sibling_calls_maintain_correct_state(self):
_NO_CHANGE = state_changes._StateChangeStates.NO_CHANGE
class Machine(state_changes._StateChange):
@state_changes._StateChange.declare_states(
state_changes._StateChangeStates.ANY, StateTestChange.c
)
def move_to_c(self):
self._state = StateTestChange.c
@state_changes._StateChange.declare_states(
state_changes._StateChangeStates.ANY, _NO_CHANGE
)
def do_nothing(self):
pass
m = Machine()
m.do_nothing()
eq_(m._state, _NO_CHANGE)
m.move_to_c()
eq_(m._state, StateTestChange.c)
def test_change_from_sub_method_requires_declaration(self):
"""A method can't call another state-changing method without using
_expect_state() to allow the state change to occur.
"""
_NO_CHANGE = state_changes._StateChangeStates.NO_CHANGE
class Machine(state_changes._StateChange):
@state_changes._StateChange.declare_states(
(StateTestChange.a, _NO_CHANGE), StateTestChange.b
)
def _inner_move_to_b(self):
self._state = StateTestChange.b
@state_changes._StateChange.declare_states(
(StateTestChange.a, _NO_CHANGE), StateTestChange.b
)
def move_to_b(self):
self._inner_move_to_b()
m = Machine()
with expect_raises_message(
sa_exc.IllegalStateChangeError,
r"Method '_inner_move_to_b\(\)' can't be called here; "
r"method 'move_to_b\(\)' is already in progress and this would "
r"cause an unexpected state change to <StateTestChange.b: 2>",
):
m.move_to_b()
|
