def test_can_get_entities_with_component(world):
a = world.create_entity()
b = world.create_entity()
c = world.create_entity()
d = world.create_entity()
a.add(SomeComponent())
b.add(AnotherComponent())
c.add(SomeComponent())
c.add(AnotherComponent())
assert list(world.entities_with(SomeComponent)) == [a, c]
assert list(world.entities_with(AnotherComponent)) == [b, c]
def test_destroyed_entities_are_forgotten(world):
entity = world.create_entity()
component = Component()
entity.add(component)
world.destroy_entitiy(entity)
assert entity not in world.entities
assert entity not in world.entities_with(Component)
assert entity.get(Component, None) is None
