def test_popped_layer_is_no_longer_used(self):
bottom_canary = Canary()
top_canary = Canary()
with dependency_context() as bottom_context:
bottom_context.inject(Canary, SingletonClass(bottom_canary))
with dependency_context() as top_context:
top_context.inject(Canary, SingletonClass(top_canary))
touch_a_canary()
expect(top_canary.touched).to(be_false)
def test_pops_top_layer_off_the_stack(self):
bottom_canary = Canary()
top_canary = Canary()
with dependency_context() as bottom_context:
bottom_context.inject(Canary, SingletonClass(bottom_canary))
with dependency_context() as top_context:
top_context.inject(Canary, SingletonClass(top_canary))
touch_a_canary()
expect(bottom_canary.touched).to(be_true)
def test_does_not_use_object_injected_lower_in_stack(self):
bottom_canary = Canary()
top_canary = Canary()
with dependency_context() as bottom_context:
bottom_context.inject(Canary, SingletonClass(bottom_canary))
with dependency_context() as top_context:
top_context.inject(Canary, SingletonClass(top_canary))
touch_a_canary()
expect(bottom_canary.touched).to(be_false)
def test_uses_object_injected_at_top_of_stack(self):
bottom_canary = Canary()
top_canary = Canary()
with dependency_context() as bottom_context:
bottom_context.inject(Canary, SingletonClass(bottom_canary))
with dependency_context() as top_context:
top_context.inject(Canary, SingletonClass(top_canary))
touch_a_canary()
expect(top_canary.touched).to(be_true)
def inject_as_class(self, dependency, injected):
"""
Inject an object as though it were a class.
When the victim requests the class, the injector returns
a SingletonClass which wraps the injected object.
"""
self.inject(dependency, SingletonClass(injected))
def test_simple_injection(self):
my_canary = Canary()
context = open_dependency_context()
context.inject(Canary, SingletonClass(my_canary))
touch_a_canary()
context.close()
expect(my_canary.touched).to(be_true)
def test_injection_does_not_affect_another_thread(self):
my_canary = Canary()
with dependency_context() as context:
context.inject(Canary, SingletonClass(my_canary))
t = Thread(target=touch_a_canary)
t.start()
t.join()
expect(my_canary.touched).to(be_false)