Add some functionality and tests for declarative containers

+ Add checks for valid provider type
+ Add some wider functionality for overriding

dependency_injector/containers.py

@@ -3,6 +3,7 @@
 import six
 
 from dependency_injector import (
+    providers,
     utils,
     errors,
 )
@@ -18,7 +19,8 @@ class DeclarativeContainerMetaClass(type):
                               if utils.is_provider(provider))
 
         inherited_providers = tuple((name, provider)
-                                    for base in bases if utils.is_catalog(base)
+                                    for base in bases if utils.is_container(
+                                        base)
                                     for name, provider in six.iteritems(
                                         base.cls_providers))
 
@@ -28,14 +30,8 @@ class DeclarativeContainerMetaClass(type):
 
         cls = type.__new__(mcs, class_name, bases, attributes)
 
-        if cls.provider_type:
-            for provider in six.itervalues(cls.providers):
-                try:
-                    assert isinstance(provider, cls.provider_type)
-                except AssertionError:
-                    raise errors.Error('{0} can contain only {1} '
-                                       'instances'.format(cls,
-                                                          cls.provider_type))
+        for provider in six.itervalues(cls.providers):
+            cls._check_provider_type(provider)
 
         return cls
 
@@ -46,6 +42,7 @@ class DeclarativeContainerMetaClass(type):
         dictionary.
         """
         if utils.is_provider(value):
+            cls._check_provider_type(value)
             cls.providers[name] = value
             cls.cls_providers[name] = value
         super(DeclarativeContainerMetaClass, cls).__setattr__(name, value)
@@ -61,14 +58,19 @@ class DeclarativeContainerMetaClass(type):
             del cls.cls_providers[name]
         super(DeclarativeContainerMetaClass, cls).__delattr__(name)
 
+    def _check_provider_type(cls, provider):
+        if not isinstance(provider, cls.provider_type):
+            raise errors.Error('{0} can contain only {1} '
+                               'instances'.format(cls, cls.provider_type))
+
 
 @six.add_metaclass(DeclarativeContainerMetaClass)
 class DeclarativeContainer(object):
     """Declarative inversion of control container."""
 
-    __IS_CATALOG__ = True
+    __IS_CONTAINER__ = True
 
-    provider_type = None
+    provider_type = providers.Provider
 
     providers = dict()
     cls_providers = dict()
@@ -89,7 +91,7 @@ class DeclarativeContainer(object):
         :rtype: None
         """
         if issubclass(cls, overriding):
-            raise errors.Error('Catalog {0} could not be overridden '
+            raise errors.Error('Container {0} could not be overridden '
                                'with itself or its subclasses'.format(cls))
 
         cls.overridden_by += (overriding,)
@@ -100,6 +102,31 @@ class DeclarativeContainer(object):
             except AttributeError:
                 pass
 
+    @classmethod
+    def reset_last_overriding(cls):
+        """Reset last overriding provider for each container providers.
+
+        :rtype: None
+        """
+        if not cls.overridden_by:
+            raise errors.Error('Container {0} is not overridden'.format(cls))
+
+        cls.overridden_by = cls.overridden_by[:-1]
+
+        for provider in six.itervalues(cls.providers):
+            provider.reset_last_overriding()
+
+    @classmethod
+    def reset_override(cls):
+        """Reset all overridings for each container providers.
+
+        :rtype: None
+        """
+        cls.overridden_by = tuple()
+
+        for provider in six.itervalues(cls.providers):
+            provider.reset_override()
+
 
 def override(container):
     """:py:class:`DeclarativeContainer` overriding decorator.

dependency_injector/providers/base.py

@@ -64,7 +64,7 @@ class Provider(object):
 
     def __init__(self):
         """Initializer."""
-        self.overridden_by = None
+        self.overridden_by = tuple()
         super(Provider, self).__init__()
         # Enable __call__() / _provide() optimization
         if self.__class__.__OPTIMIZED_CALLS__:
@@ -124,10 +124,7 @@ class Provider(object):
         if not is_provider(provider):
             provider = Object(provider)
 
-        if not self.is_overridden:
-            self.overridden_by = (ensure_is_provider(provider),)
-        else:
-            self.overridden_by += (ensure_is_provider(provider),)
+        self.overridden_by += (ensure_is_provider(provider),)
 
         # Disable __call__() / _provide() optimization
         if self.__class__.__OPTIMIZED_CALLS__:
@@ -145,6 +142,7 @@ class Provider(object):
         """
         if not self.overridden_by:
             raise Error('Provider {0} is not overridden'.format(str(self)))
+
         self.overridden_by = self.overridden_by[:-1]
 
         if not self.is_overridden:
@@ -157,7 +155,7 @@ class Provider(object):
 
         :rtype: None
         """
-        self.overridden_by = None
+        self.overridden_by = tuple()
 
         # Enable __call__() / _provide() optimization
         if self.__class__.__OPTIMIZED_CALLS__:

dependency_injector/utils.py

@@ -59,6 +59,18 @@ def ensure_is_provider(instance):
     return instance
 
 
+def is_container(instance):
+    """Check if instance is container instance.
+
+    :param instance: Instance to be checked.
+    :type instance: object
+
+    :rtype: bool
+    """
+    return (hasattr(instance, '__IS_CONTAINER__') and
+            getattr(instance, '__IS_CONTAINER__', False) is True)
+
+
 def is_catalog(instance):
     """Check if instance is catalog instance.
 

tests/test_containers.py

@@ -5,6 +5,7 @@ import unittest2 as unittest
 from dependency_injector import (
     containers,
     providers,
+    errors,
 )
 
 
@@ -28,7 +29,7 @@ class ContainerB(ContainerA):
 class DeclarativeContainerTests(unittest.TestCase):
     """Declarative container tests."""
 
-    def test_providers_attribute_with(self):
+    def test_providers_attribute(self):
         """Test providers attribute."""
         self.assertEqual(ContainerA.providers, dict(p11=ContainerA.p11,
                                                     p12=ContainerA.p12))
@@ -37,7 +38,7 @@ class DeclarativeContainerTests(unittest.TestCase):
                                                     p21=ContainerB.p21,
                                                     p22=ContainerB.p22))
 
-    def test_cls_providers_attribute_with(self):
+    def test_cls_providers_attribute(self):
         """Test cls_providers attribute."""
         self.assertEqual(ContainerA.cls_providers, dict(p11=ContainerA.p11,
                                                         p12=ContainerA.p12))
@@ -51,7 +52,7 @@ class DeclarativeContainerTests(unittest.TestCase):
                          dict(p11=ContainerA.p11,
                               p12=ContainerA.p12))
 
-    def test_set_get_del_provider_attribute(self):
+    def test_set_get_del_providers(self):
         """Test set/get/del provider attributes."""
         a_p13 = providers.Provider()
         b_p23 = providers.Provider()
@@ -90,6 +91,120 @@ class DeclarativeContainerTests(unittest.TestCase):
         self.assertEqual(ContainerB.cls_providers, dict(p21=ContainerB.p21,
                                                         p22=ContainerB.p22))
 
+    def test_declare_with_valid_provider_type(self):
+        """Test declaration of container with valid provider type."""
+        class _Container(containers.DeclarativeContainer):
+            provider_type = providers.Object
+            px = providers.Object(object())
+
+        self.assertIsInstance(_Container.px, providers.Object)
+
+    def test_declare_with_invalid_provider_type(self):
+        """Test declaration of container with invalid provider type."""
+        with self.assertRaises(errors.Error):
+            class _Container(containers.DeclarativeContainer):
+                provider_type = providers.Object
+                px = providers.Provider()
+
+    def test_seth_valid_provider_type(self):
+        """Test setting of valid provider."""
+        class _Container(containers.DeclarativeContainer):
+            provider_type = providers.Object
+
+        _Container.px = providers.Object(object())
+
+        self.assertIsInstance(_Container.px, providers.Object)
+
+    def test_set_invalid_provider_type(self):
+        """Test setting of invalid provider."""
+        class _Container(containers.DeclarativeContainer):
+            provider_type = providers.Object
+
+        with self.assertRaises(errors.Error):
+            _Container.px = providers.Provider()
+
+    def test_override(self):
+        """Test override."""
+        class _Container(containers.DeclarativeContainer):
+            p11 = providers.Provider()
+
+        class _OverridingContainer1(containers.DeclarativeContainer):
+            p11 = providers.Provider()
+
+        class _OverridingContainer2(containers.DeclarativeContainer):
+            p11 = providers.Provider()
+            p12 = providers.Provider()
+
+        _Container.override(_OverridingContainer1)
+        _Container.override(_OverridingContainer2)
+
+        self.assertEqual(_Container.overridden_by,
+                         (_OverridingContainer1,
+                          _OverridingContainer2))
+        self.assertEqual(_Container.p11.overridden_by,
+                         (_OverridingContainer1.p11,
+                          _OverridingContainer2.p11))
+
+    def test_override_decorator(self):
+        """Test override decorator."""
+        class _Container(containers.DeclarativeContainer):
+            p11 = providers.Provider()
+
+        @containers.override(_Container)
+        class _OverridingContainer1(containers.DeclarativeContainer):
+            p11 = providers.Provider()
+
+        @containers.override(_Container)
+        class _OverridingContainer2(containers.DeclarativeContainer):
+            p11 = providers.Provider()
+            p12 = providers.Provider()
+
+        self.assertEqual(_Container.overridden_by,
+                         (_OverridingContainer1,
+                          _OverridingContainer2))
+        self.assertEqual(_Container.p11.overridden_by,
+                         (_OverridingContainer1.p11,
+                          _OverridingContainer2.p11))
+
+    def test_reset_last_overridding(self):
+        """Test reset of last overriding."""
+        class _Container(containers.DeclarativeContainer):
+            p11 = providers.Provider()
+
+        class _OverridingContainer1(containers.DeclarativeContainer):
+            p11 = providers.Provider()
+
+        class _OverridingContainer2(containers.DeclarativeContainer):
+            p11 = providers.Provider()
+            p12 = providers.Provider()
+
+        _Container.override(_OverridingContainer1)
+        _Container.override(_OverridingContainer2)
+        _Container.reset_last_overriding()
+
+        self.assertEqual(_Container.overridden_by,
+                         (_OverridingContainer1,))
+        self.assertEqual(_Container.p11.overridden_by,
+                         (_OverridingContainer1.p11,))
+
+    def test_reset_override(self):
+        """Test reset all overridings."""
+        class _Container(containers.DeclarativeContainer):
+            p11 = providers.Provider()
+
+        class _OverridingContainer1(containers.DeclarativeContainer):
+            p11 = providers.Provider()
+
+        class _OverridingContainer2(containers.DeclarativeContainer):
+            p11 = providers.Provider()
+            p12 = providers.Provider()
+
+        _Container.override(_OverridingContainer1)
+        _Container.override(_OverridingContainer2)
+        _Container.reset_override()
+
+        self.assertEqual(_Container.overridden_by, tuple())
+        self.assertEqual(_Container.p11.overridden_by, tuple())
 
 if __name__ == '__main__':
     unittest.main()