Container.reset_singletons() (#390)

* Rename container tests

* Add implementation + tests

* Update changelog

* Add examples and docs

docs/containers/index.rst

@@ -23,4 +23,5 @@ Containers module API docs - :py:mod:`dependency_injector.containers`.
     dynamic
     specialization
     overriding
+    reset_singletons
     traversal

docs/containers/reset_singletons.rst

@@ -0,0 +1,19 @@
+Reset container singletons
+--------------------------
+
+To reset all container singletons use method ``.reset_singletons()``.
+
+.. literalinclude:: ../../examples/containers/reset_singletons.py
+   :language: python
+   :lines: 3-
+   :emphasize-lines: 16
+
+Method ``.reset_singletons()`` also resets singletons in sub-containers: ``providers.Container`` and
+``providers.DependenciesContainer.``
+
+.. literalinclude:: ../../examples/containers/reset_singletons_subcontainers.py
+   :language: python
+   :lines: 3-
+   :emphasize-lines: 21
+
+.. disqus::

docs/main/changelog.rst

@@ -9,6 +9,7 @@ follows `Semantic versioning`_
 
 Development version
 -------------------
+- Add ``container.reset_singleton()`` method to reset container singletons.
 - Refactor ``container.apply_container_providers_overridings()`` to use ``container.traverse()``.
   This enables deep lazy initialization of ``Container`` providers.
 - Add tests for ``Selector`` provider.

examples/containers/reset_singletons.py

@@ -0,0 +1,21 @@
+"""Container reset singletons example."""
+
+from dependency_injector import containers, providers
+
+
+class Container(containers.DeclarativeContainer):
+
+    service1 = providers.Singleton(object)
+    service2 = providers.Singleton(object)
+
+
+if __name__ == '__main__':
+    container = Container()
+
+    service1 = container.service1()
+    service2 = container.service2()
+
+    container.reset_singletons()
+
+    assert service1 is not container.service1()
+    assert service2 is not container.service2()

examples/containers/reset_singletons_subcontainers.py

@@ -0,0 +1,26 @@
+"""Container reset singletons in subcontainer example."""
+
+from dependency_injector import containers, providers
+
+
+class SubContainer(containers.DeclarativeContainer):
+
+    service = providers.Singleton(object)
+
+
+class Container(containers.DeclarativeContainer):
+
+    service = providers.Singleton(object)
+    sub = providers.Container(SubContainer)
+
+
+if __name__ == '__main__':
+    container = Container()
+
+    service1 = container.service()
+    service2 = container.sub().service()
+
+    container.reset_singletons()
+
+    assert service1 is not container.service()
+    assert service2 is not container.sub().service()

src/dependency_injector/containers.pyi

@@ -43,6 +43,8 @@ class Container:
     def unwire(self) -> None: ...
     def init_resources(self) -> Optional[Awaitable]: ...
     def shutdown_resources(self) -> Optional[Awaitable]: ...
+    def apply_container_providers_overridings(self) -> None: ...
+    def reset_singletons(self) -> None: ...
     @overload
     def traverse(self, types: Optional[Sequence[Type]] = None) -> Iterator[Provider]: ...
     @classmethod

src/dependency_injector/containers.pyx

@@ -271,6 +271,11 @@ class DynamicContainer(Container):
         for provider in self.traverse(types=[providers.Container]):
             provider.apply_overridings()
 
+    def reset_singletons(self):
+        """Reset all container singletons."""
+        for provider in self.traverse(types=[providers.Singleton]):
+            provider.reset()
+
 
 class DeclarativeContainerMetaClass(type):
     """Declarative inversion of control container meta class."""

tests/unit/containers/test_dynamic_py2_py3.py

@@ -140,7 +140,7 @@ class DeclarativeContainerInstanceTests(unittest.TestCase):
         with self.assertRaises(AttributeError):
             container_a.override_providers(unknown=providers.Provider())
 
-    def test_reset_last_overridding(self):
+    def test_reset_last_overriding(self):
         class _Container(containers.DeclarativeContainer):
             p11 = providers.Provider()
 
@@ -164,7 +164,7 @@ class DeclarativeContainerInstanceTests(unittest.TestCase):
         self.assertEqual(container.p11.overridden,
                          (overriding_container1.p11,))
 
-    def test_reset_last_overridding_when_not_overridden(self):
+    def test_reset_last_overriding_when_not_overridden(self):
         container = ContainerA()
 
         with self.assertRaises(errors.Error):
@@ -287,3 +287,51 @@ class DeclarativeContainerInstanceTests(unittest.TestCase):
         self.assertEqual(_init1.shutdown_counter, 2)
         self.assertEqual(_init2.init_counter, 2)
         self.assertEqual(_init2.shutdown_counter, 2)
+
+    def reset_singletons(self):
+        class SubSubContainer(containers.DeclarativeContainer):
+            singleton = providers.Singleton(object)
+
+        class SubContainer(containers.DeclarativeContainer):
+            singleton = providers.Singleton(object)
+            sub_sub_container = providers.Container(SubSubContainer)
+
+        class Container(containers.DeclarativeContainer):
+            singleton = providers.Singleton(object)
+            sub_container = providers.Container(SubContainer)
+
+        container = Container()
+
+        obj11 = container.singleton()
+        obj12 = container.sub_container().singleton()
+        obj13 = container.sub_container().sub_sub_container().singleton()
+
+        obj21 = container.singleton()
+        obj22 = container.sub_container().singleton()
+        obj23 = container.sub_container().sub_sub_container().singleton()
+
+        self.assertIs(obj11, obj21)
+        self.assertIs(obj12, obj22)
+        self.assertIs(obj13, obj23)
+
+        container.reset_singletons()
+
+        obj31 = container.singleton()
+        obj32 = container.sub_container().singleton()
+        obj33 = container.sub_container().sub_sub_container().singleton()
+
+        obj41 = container.singleton()
+        obj42 = container.sub_container().singleton()
+        obj43 = container.sub_container().sub_sub_container().singleton()
+
+        self.assertIsNot(obj11, obj31)
+        self.assertIsNot(obj12, obj32)
+        self.assertIsNot(obj13, obj33)
+
+        self.assertIsNot(obj21, obj31)
+        self.assertIsNot(obj22, obj32)
+        self.assertIsNot(obj23, obj33)
+
+        self.assertIs(obj31, obj41)
+        self.assertIs(obj32, obj42)
+        self.assertIs(obj33, obj43)