add failing test for issue #17

Author: RonnyPfannschmidt

testing/test_pluggy.py

@@ -656,6 +656,20 @@ def hello_myhook(self, arg1):
         results = pm.hook.hello_myhook(arg1=17)
         assert results == [18, 18]
 
+    def test_prefix_hookimpl_dontmatch_module(self):
+        pm = PluginManager(hookspec.project_name, "hello_")
+
+        class BadPlugin:
+            def hello_fine(self):
+                pass
+            hello_fine.optionalhook = True
+
+            hello_module = __import__('email')
+
+        pm.register(BadPlugin())
+        pm.check_pending()
+
+
 
 def test_parse_hookimpl_override():
     class MyPluginManager(PluginManager):