ipatests.order_plugin: Exclude test generators from the order

Ordered test generators were not announced in plugin hooks, so
e.g. the Beakerlib or collect plugin did not announce them.

Exclude test generators from ordering.

ipatests/order_plugin.py

@@ -25,10 +25,19 @@ import inspect
 
 from nose.plugins import Plugin
 import nose.loader
+import nose.util
 
 
 def ordered(cls):
-    """Decorator that marks a test class as ordered"""
+    """Decorator that marks a test class as ordered
+
+    Methods within the marked class will be executed in definition order
+    (or more strictly, in ordered by the line number where they're defined).
+
+    Subclasses of unittest.TestCase can not be ordered.
+
+    Generator methods will not be ordered by this plugin.
+    """
     cls._order_plugin__ordered = True
     assert not isinstance(cls, unittest.TestCase), (
         "A unittest.TestCase may not be ordered.")
@@ -56,6 +65,8 @@ class OrderTests(Plugin):
             item = getattr(cls, attr, None)
             if not inspect.ismethod(item):
                 return False
+            if nose.util.isgenerator(item.im_func):
+                return False
             return loader.selector.wantMethod(item)
 
         methods = [getattr(cls, case) for case in dir(cls) if wanted(case)]
@@ -67,4 +78,6 @@ class OrderTests(Plugin):
         """Hide non-TestCase methods from the normal loader"""
         im_class = getattr(method, 'im_class', None)
         if im_class and getattr(im_class, '_order_plugin__ordered', False):
+            if nose.util.isgenerator(method.im_func):
+                return True
             return False