Validates python type of ObjectGraph.provide() arg.

TODO

@@ -1,15 +1,14 @@
 TODO:
-- validate python types of all input
 - allow binding specs to declare required bindings
-- standard tests for scopes (reentrant? thread-safe?), annotations (eq?
-     hash?), etc.
 - describe features specifically omitted, e.g.,
   - field injection
   - circular injection
   - scope annotations on classes
 - figure out whether/how Pinject works with inheritance
 
 Maybe TODO:
+- standard tests for scopes (reentrant? thread-safe?), annotations (eq?
+     hash?), etc.
 - change default scope back to prototype?
 - eager singletons
 - allow field injection

pinject/object_graph.py

@@ -148,6 +148,12 @@ def new_object_graph(
         use_short_stack_traces)
 
 
+def _verify_type(elt, required_type, arg_name):
+    if type(elt) != required_type:
+        raise errors.WrongArgTypeError(
+            arg_name, required_type.__name__, type(elt).__name__)
+
+
 def _verify_types(seq, required_type, arg_name):
     if not isinstance(seq, collections.Sequence):
         raise errors.WrongArgTypeError(
@@ -199,6 +205,7 @@ def provide(self, cls):
         Raises:
           Error: an instance of cls is not providable
         """
+        _verify_type(cls, types.TypeType, 'cls')
         if not self._is_injectable_fn(cls):
             provide_loc = locations.get_back_frame_loc()
             raise errors.NonExplicitlyBoundClassError(provide_loc, cls)

pinject/object_graph_test.py

@@ -145,6 +145,16 @@ def test_raises_exception_if_is_scope_usable_from_scope_is_wrong_type(self):
                           is_scope_usable_from_scope=42)
 
 
+class VerifyTypeTest(unittest.TestCase):
+
+    def test_verifies_correct_type_ok(self):
+        object_graph._verify_type(types, types.ModuleType, 'unused')
+
+    def test_raises_exception_if_incorrect_type(self):
+        self.assertRaises(errors.WrongArgTypeError, object_graph._verify_type,
+                          'not-a-module', types.ModuleType, 'an-arg-name')
+
+
 class VerifyTypesTest(unittest.TestCase):
 
     def test_verifies_empty_sequence_ok(self):
@@ -540,6 +550,13 @@ def provide_foo(self):
         self.assertRaises(errors.InjectingNoneDisallowedError,
                           obj_graph.provide, SomeClass)
 
+    def test_raises_exception_if_trying_to_provide_nonclass(self):
+        class SomeClass(object):
+            pass
+        obj_graph = object_graph.new_object_graph(
+            modules=None, classes=[SomeClass])
+        self.assertRaises(errors.WrongArgTypeError, obj_graph.provide, 42)
+
 
 class ObjectGraphWrapTest(unittest.TestCase):