get_classes now allows top-level apps.

Fixes #614

oscar/core/loading.py

@@ -44,8 +44,11 @@ class can't be found in the overriding module, then we attempt to import it
     # App must be local - check if module is in local app (it could be in
     # oscar's)
     app_label = module_label.split('.')[0]
-    base_package = app_module_path.rsplit('.' + app_label, 1)[0]
-    local_app = "%s.%s" % (base_package, module_label)
+    if '.' in app_module_path:
+        base_package = app_module_path.rsplit('.' + app_label, 1)[0]
+        local_app = "%s.%s" % (base_package, module_label)
+    else:
+        local_app = module_label
     try:
         imported_local_module = __import__(local_app, fromlist=classnames)
     except ImportError:

tests/__init__.py

@@ -0,0 +1,17 @@
+import sys
+
+
+class temporary_python_path(object):
+    """
+    Acts as a context manager to temporarily append a list of paths to sys.path
+    """
+
+    def __init__(self, paths):
+        self.paths = paths
+
+    def __enter__(self):
+        self.original_paths = sys.path[:]
+        sys.path = self.paths + self.original_paths
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        sys.path = self.original_paths

tests/unit/core/loading_tests.py

@@ -1,3 +1,4 @@
+from os.path import dirname
 from django.test import TestCase
 from django.core.exceptions import ValidationError
 from django.conf import settings
@@ -9,6 +10,7 @@
         get_classes, get_class, ClassNotFoundError
 from oscar.core.validators import ExtendedURLValidator
 from oscar.core.validators import URLDoesNotExistValidator
+from tests import temporary_python_path
 
 
 class TestImportModule(TestCase):
@@ -78,6 +80,15 @@ def test_loading_classes_defined_in_both_local_and_oscar_modules(self):
             self.assertEqual('tests._site.shipping.methods', Free.__module__)
             self.assertEqual('oscar.apps.shipping.methods', FixedPrice.__module__)
 
+    def test_loading_classes_with_root_app(self):
+        import tests._site.shipping
+        path = dirname(dirname(tests._site.shipping.__file__))
+        with temporary_python_path([path]):
+            self.installed_apps[self.installed_apps.index('tests._site.shipping')] = 'shipping'
+            with override_settings(INSTALLED_APPS=self.installed_apps):
+                (Free,) = get_classes('shipping.methods', ('Free',))
+                self.assertEqual('shipping.methods', Free.__module__)
+
 
 class TestExtendedURLValidator(TestCase):
     """