Add strict mode + tests

src/dependency_injector/providers.pxd

@@ -107,6 +107,7 @@ cdef class TypedConfigurationOption(Callable):
 
 cdef class Configuration(Object):
     cdef str __name
+    cdef bint __strict
     cdef dict __children
     cdef object __weakref__
 

src/dependency_injector/providers.pyi

@@ -160,7 +160,7 @@ class TypedConfigurationOption(Callable[T]):
 
 class Configuration(Object[Any]):
     DEFAULT_NAME: str = 'config'
-    def __init__(self, name: str = DEFAULT_NAME, default: Optional[Any] = None) -> None: ...
+    def __init__(self, name: str = DEFAULT_NAME, default: Optional[Any] = None, *, strict: bool = False) -> None: ...
     def __getattr__(self, item: str) -> ConfigurationOption: ...
     def __getitem__(self, item: Union[str, Provider]) -> ConfigurationOption: ...
     def get_name(self) -> str: ...

src/dependency_injector/providers.pyx

@@ -1396,9 +1396,11 @@ cdef class Configuration(Object):
     """
 
     DEFAULT_NAME = 'config'
+    UNDEFINED = object()
 
-    def __init__(self, name=DEFAULT_NAME, default=None):
+    def __init__(self, name=DEFAULT_NAME, default=None, strict=False):
         self.__name = name
+        self.__strict = strict
 
         value = {}
         if default is not None:
@@ -1416,7 +1418,7 @@ cdef class Configuration(Object):
         if copied is not None:
             return copied
 
-        copied = self.__class__(self.__name, self.__provides)
+        copied = self.__class__(self.__name, self.__provides, self.__strict)
         memo[id(self)] = copied
 
         copied.__children = deepcopy(self.__children, memo)
@@ -1467,9 +1469,12 @@ cdef class Configuration(Object):
 
         while len(keys) > 0:
             key = keys.pop(0)
-            value = value.get(key)
-            if value is None:
-                break
+            value = value.get(key, self.UNDEFINED)
+
+            if value is self.UNDEFINED:
+                if self.__strict:
+                    raise Error('Undefined configuration option "{0}.{1}"'.format(self.__name, selector))
+                return None
 
         return value
 

tests/unit/providers/test_configuration_py2_py3.py

@@ -176,6 +176,11 @@ class ConfigTests(unittest.TestCase):
     def test_value_of_undefined_option(self):
         self.assertIsNone(self.config.a())
 
+    def test_value_of_undefined_option_in_strict_mode(self):
+        self.config = providers.Configuration(strict=True)
+        with self.assertRaisesRegex(errors.Error, 'Undefined configuration option "config.a"'):
+            self.config.a()
+
     def test_getting_of_special_attributes(self):
         with self.assertRaises(AttributeError):
             self.config.__name__