def test_snapshot_state_after_versioning_events(self):
"""
Mimick evolution of an event class, from original to version 2.
Could/should just test reconstruct_object() calls __upcast_state__,
but this test is decoupled from implementation, and simply checks
upcasting is active when storing and retrieving aggregate state.
"""
app = SnapshottingApplication.mixin(SQLAlchemyApplication)(
persist_event_type=BaseAggregateRoot.Event, )
with app:
my_aggregate = MultiVersionAggregateFixture.__create__()
# Trigger without any kwargs (original behaviour).
my_aggregate.trigger()
my_aggregate.__save__()
# Take a snapshot.
app.repository.take_snapshot(my_aggregate.id)
# Check the default values are used for value and units.
copy = app.repository[my_aggregate.id]
assert isinstance(copy, MultiVersionAggregateFixture)
self.assertEqual(copy.value, None)
self.assertEqual(copy.units, None)
# Increase the version of the aggregate and event class.
MultiVersionAggregateFixture.__class_version__ = 1
MultiVersionAggregateFixture.Triggered.__class_version__ = 1
MultiVersionAggregateFixture.Triggered.__upcast__ = (
MultiVersionAggregateFixture.Triggered.upcast_v1)
MultiVersionAggregateFixture.Triggered.mutate = (
MultiVersionAggregateFixture.Triggered.mutate_v1)
# Check v1 code upcasts snapshot (which doesnt have 'value').
copy = app.repository[my_aggregate.id]
assert isinstance(copy, MultiVersionAggregateFixture)
self.assertEqual(copy.value, 0) # gets default
self.assertEqual(copy.units, None)
# Trigger with value kwarg (first version behaviour).
my_aggregate.trigger(value=10)
my_aggregate.__save__()
# Check v1 code can read original and first event versions.
copy = app.repository[my_aggregate.id]
assert isinstance(copy, MultiVersionAggregateFixture)
self.assertEqual(copy.value, 10)
self.assertEqual(copy.units, None)
# Take a snapshot.
app.repository.take_snapshot(my_aggregate.id)
# Check the default values are used for value and units.
copy = app.repository[my_aggregate.id]
assert isinstance(copy, MultiVersionAggregateFixture)
self.assertEqual(copy.value, 10)
self.assertEqual(copy.units, None)
# Increase the version of the aggregate and event class.
MultiVersionAggregateFixture.__class_version__ = 2
MultiVersionAggregateFixture.Triggered.__class_version__ = 2
MultiVersionAggregateFixture.Triggered.__upcast__ = (
MultiVersionAggregateFixture.Triggered.upcast_v2)
MultiVersionAggregateFixture.Triggered.mutate = (
MultiVersionAggregateFixture.Triggered.mutate_v2)
# Check v2 code upcasts snapshot (which doesnt have 'units').
copy = app.repository[my_aggregate.id]
assert isinstance(copy, MultiVersionAggregateFixture)
self.assertEqual(copy.value, 10)
self.assertEqual(copy.units, '') # gets default
class TestSnapshottingApplication(TestSimpleApplication):
infrastructure_class = SnapshottingApplication.mixin(SQLAlchemyApplication)
class TestSnapshottingAxonApplication(TestSimpleApplication):
infrastructure_class = SnapshottingApplication.mixin(AxonApplication)
class TestSnapshottingApplication(TestSimpleApplication):
application_class = SnapshottingApplication.mixin(SQLAlchemyApplication)