fix for issue binarymatt#26

changed the safe_str_to_class to raise an ImportError
instead of returning None.

Author: Matt George

pyres/__init__.py

@@ -19,15 +19,12 @@ def safe_str_to_class(s):
     klass = lst[-1]
     mod_list = lst[:-1]
     module = ".".join(mod_list)
-    try:
-        mod = my_import(module)
-        if hasattr(mod, klass):
-            return getattr(mod, klass)
-        else:
-            return None
-    except ImportError:
-        return None
-
+    mod = my_import(module)
+    if hasattr(mod, klass):
+        return getattr(mod, klass)
+    else:
+        raise ImportError('')
+    
 def str_to_class(s):
     """Alternate helper function to map string class names to module classes."""
     lst = s.split(".")

tests/__init__.py

@@ -50,11 +50,13 @@ def test_str_to_class():
     assert ret == Basic
     assert str_to_class('hello.World') == None
 
-def test_safe_str_to_class():
-    from pyres import safe_str_to_class
-    assert safe_str_to_class('tests.Basic') == Basic
-    assert safe_str_to_class('test.Mine') == None
-    assert safe_str_to_class('hello.World') == None
+class ImportTest(unittest.TestCase):
+    def test_safe_str_to_class(self):
+        from pyres import safe_str_to_class
+        assert safe_str_to_class('tests.Basic') == Basic
+        self.assertRaises(ImportError, safe_str_to_class, 'test.Mine')
+        self.assertRaises(ImportError, safe_str_to_class, 'tests.World')
+    
 
 class PyResTests(unittest.TestCase):
     def setUp(self):