def test_can_add_components_to_entities(world):
entity = world.create_entity()
component = Component()
assert not world.has_component(entity, Component)
world.add_component(entity, component)
assert world.has_component(entity, Component)
assert world.get_component(entity, Component) is component
def test_can_remove_components(world):
entity = world.create_entity()
component = Component()
world.add_component(entity, component)
assert world.has_component(entity, Component)
world.remove_component(entity, Component)
assert not world.has_component(entity, Component)
def test_adding_a_duplicate_component_is_an_error(world):
entity = world.create_entity()
world.add_component(entity, Component())
with pytest.raises(DuplicateComponentError):
world.add_component(entity, Component())
