Add helpful error message when dealing with old-style classes

--HG--
extra : rebase_source : f94bedeb736bf453bf8d1a38fa50f9bfd47cd249

CHANGELOG.txt

@@ -1,3 +1,6 @@
+0.3.2 (2014-01-02)
+    * Add helpful error message when used with old-style classes.
+
 0.3.1 (2013-08-01)
 
     * Fix bug: `nose_parameterized.param` wasn't being imported.

nose_parameterized/parameterized.py

@@ -11,9 +11,14 @@ from . import six
 if six.PY3:
     def new_instancemethod(f, *args):
         return f
+
+    # Python 3 doesn't have an InstanceType, so just use a dummy type.
+    class InstanceType():
+        pass
 else:
     import new
     new_instancemethod = new.instancemethod
+    from types import InstanceType
 
 _param = namedtuple("param", "args kwargs")
 
@@ -140,6 +145,14 @@ class parameterized(object):
 
     def make_bound_method(self, instance, func):
         cls = type(instance)
+        if issubclass(cls, InstanceType):
+            raise TypeError((
+                "@parameterized can't be used with old-style classes, but "
+                "%r has an old-style class. Consider using a new-style "
+                "class, or '@parameterized.expand' "
+                "(see http://stackoverflow.com/q/54867/71522 for more "
+                "information on old-style classes)."
+            ) %(instance, ))
         im_f = new_instancemethod(func, None, cls)
         setattr(cls, func.__name__, im_f)
         return getattr(instance, func.__name__)
@@ -164,8 +177,8 @@ class parameterized(object):
         code_context = frame[4] and frame[4][0].strip()
         if not (code_context and code_context.startswith("class ")):
             return []
-        _, parents = code_context.split("(", 1)
-        parents, _ = parents.rsplit(")", 1)
+        _, _, parents = code_context.partition("(")
+        parents, _, _ = parents.partition(")")
         return eval("[" + parents + "]", frame[0].f_globals, frame[0].f_locals)
 
     @classmethod

nose_parameterized/test.py

@@ -1,6 +1,8 @@
 from unittest import TestCase
 from nose.tools import assert_equal
+from nose.plugins.skip import SkipTest
 
+from . import six
 from .parameterized import parameterized, param
 
 def assert_contains(haystack, needle):
@@ -20,6 +22,8 @@ missing_tests = set([
     "test_on_TestCase('foo0', bar=None)",
     "test_on_TestCase('foo1', bar=None)",
     "test_on_TestCase('foo2', bar=42)",
+    "test_on_old_style_class('foo')",
+    "test_on_old_style_class('bar')",
 ])
 
 test_params = [
@@ -75,3 +79,26 @@ def test_helpful_error_on_non_iterable_input():
 def teardown_module():
     missing = sorted(list(missing_tests))
     assert_equal(missing, [])
+
+
+def test_old_style_classes():
+    if six.PY3:
+        raise SkipTest("Py3 doesn't have old-style classes")
+    class OldStyleClass:
+        @parameterized(["foo"])
+        def parameterized_method(self, param):
+            pass
+    try:
+        list(OldStyleClass().parameterized_method())
+    except TypeError as e:
+        assert_contains(str(e), "new-style")
+        assert_contains(str(e), "parameterized.expand")
+        assert_contains(str(e), "OldStyleClass")
+    else:
+        raise AssertionError("expected TypeError not raised by old-style class")
+
+
+class TestOldStyleClass:
+    @parameterized.expand(["foo", "bar"])
+    def test_old_style_classes(self, param):
+        missing_tests.remove("test_on_old_style_class(%r)" %(param, ))

setup.py

@@ -9,7 +9,7 @@ os.chdir(os.path.dirname(sys.argv[0]) or ".")
 
 setup(
     name="nose-parameterized",
-    version="0.3.1",
+    version="0.3.2",
     url="https://github.com/wolever/nose-parameterized",
     author="David Wolever",
     author_email="david@wolever.net",