Add a PendingDeprecationWarning on associated class auto-discovery.

Signed-off-by: Raphaël Barrois <raphael.barrois@polytechnique.org>

2 files changed, 35 insertions, 11 deletions

diff --git a/factory/base.py b/factory/base.py
index b2f437d..c17b7ce 100644
--- a/factory/base.py
+++ b/factory/base.py
@@ -22,6 +22,7 @@
 
 import re
 import sys
+import warnings
 
 from factory import containers
 
@@ -156,29 +157,36 @@ class FactoryMetaClass(BaseFactoryMetaClass):
         if FACTORY_CLASS_DECLARATION in attrs:
             return attrs[FACTORY_CLASS_DECLARATION]
 
+        # No specific associated calss was given, and one was defined for our
+        # parent, use it.
+        if inherited is not None:
+            return inherited
+
         if '__module__' in attrs:
             factory_module = sys.modules[attrs['__module__']]
             if class_name.endswith('Factory'):
                 # Try a module lookup
                 used_auto_discovery = True
-                associated_class_name = class_name[:-len('Factory')]
-                if associated_class_name:
-                    # Class name was longer than just 'Factory'.
-                    try:
-                        return getattr(factory_module, associated_class_name)
-                    except AttributeError:
-                        pass
+                associated_name = class_name[:-len('Factory')]
+                if associated_name and hasattr(factory_module, associated_name):
+                    warnings.warn(
+                        "Auto-discovery of associated class is deprecated, and "
+                        "will be removed in the future. Please set '%s = %s' "
+                        "in the %s class definition." % (
+                            FACTORY_CLASS_DECLARATION,
+                            associated_name,
+                            class_name,
+                        ), PendingDeprecationWarning)
+
+                    return getattr(factory_module, associated_name)
 
         # Unable to guess a good option; return the inherited class.
-        if inherited is not None:
-            return inherited
-
         # Unable to find an associated class; fail.
         if used_auto_discovery:
             raise Factory.AssociatedClassError(
                 FactoryMetaClass.ERROR_MESSAGE_AUTODISCOVERY.format(
                     FACTORY_CLASS_DECLARATION,
-                    associated_class_name,
+                    associated_name,
                     class_name,
                     factory_module,))
         else:
diff --git a/tests/test_base.py b/tests/test_base.py
index 4f77421..8da655e 100644
--- a/tests/test_base.py
+++ b/tests/test_base.py
@@ -21,6 +21,7 @@
 # THE SOFTWARE.
 
 import unittest
+import warnings
 
 from factory import base
 from factory import declarations
@@ -153,6 +154,21 @@ class FactoryCreationTestCase(unittest.TestCase):
 
         self.assertTrue(isinstance(TestObjectFactory.build(), TestObject))
 
+    def testDeprecationWarning(self):
+        """Make sure the 'auto-discovery' deprecation warning is issued."""
+
+        with warnings.catch_warnings(record=True) as w:
+            # Clear the warning registry.
+            if hasattr(base, '__warningregistry__'):
+                base.__warningregistry__.clear()
+
+            warnings.simplefilter('always')
+            class TestObjectFactory(base.Factory):
+                pass
+
+            self.assertEqual(1, len(w))
+            self.assertIn('deprecated', str(w[0].message))
+
     def testStub(self):
         class TestFactory(base.StubFactory):
             pass