diff --git a/ZCTextIndex.py b/ZCTextIndex.py
index cf60fdb..4e4e1b2 100644
--- a/ZCTextIndex.py
+++ b/ZCTextIndex.py
@@ -8,29 +8,30 @@
 # THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
 # WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 # WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
-# FOR A PARTICULAR PURPOSE
+# FOR A PARTICULAR PURPOSE.
 #
 ##############################################################################
+"""Plug in text index for ZCatalog with relevance ranking.
 
-"""Plug in text index for ZCatalog with relevance ranking."""
+$Id$
+"""
 
 from cgi import escape
-from types import TupleType
 
-import ZODB
 from Persistence import Persistent
 import Acquisition
 from Acquisition import aq_base, aq_inner, aq_parent
 from OFS.SimpleItem import SimpleItem
-
 from Globals import DTMLFile, InitializeClass
 from AccessControl.SecurityInfo import ClassSecurityInfo
 from AccessControl.Permissions import manage_zcatalog_indexes, search_zcatalog
+from zope.interface import implements
 
 from Products.PluginIndexes.common.PluggableIndex import \
      PluggableIndexInterface
 from Products.PluginIndexes.common.util import parseIndexRequest
 from Products.PluginIndexes.common import safe_callable
+from Products.PluginIndexes.interfaces import IPluggableIndex
 
 from Products.ZCTextIndex.ILexicon import ILexicon
 from Products.ZCTextIndex.Lexicon import \
@@ -38,16 +39,23 @@
 from Products.ZCTextIndex.NBest import NBest
 from Products.ZCTextIndex.QueryParser import QueryParser
 from PipelineFactory import element_factory
+from interfaces import IZCLexicon
+from interfaces import IZCTextIndex
 
 from Products.ZCTextIndex.CosineIndex import CosineIndex
 from Products.ZCTextIndex.OkapiIndex import OkapiIndex
+
 index_types = {'Okapi BM25 Rank':OkapiIndex,
                'Cosine Measure':CosineIndex}
 
+
 class ZCTextIndex(Persistent, Acquisition.Implicit, SimpleItem):
-    """Persistent TextIndex"""
+
+    """Persistent text index.
+    """
 
     __implements__ = PluggableIndexInterface
+    implements(IZCTextIndex, IPluggableIndex)
 
     ## Magic class attributes ##
 
@@ -72,7 +80,8 @@ def __init__(self, id, extra=None, caller=None, index_factory=None,
         # via the silly "extra" record.
         self._fieldname = field_name or getattr(extra, 'doc_attr', '') or id
         self._indexed_attrs = self._fieldname.split(',')
-        self._indexed_attrs = [ attr.strip() for attr in  self._indexed_attrs if attr ]
+        self._indexed_attrs = [ attr.strip()
+                                for attr in self._indexed_attrs if attr ]
 
         lexicon_id = lexicon_id or getattr(extra, 'lexicon_id', '')
         lexicon = getattr(caller, lexicon_id, None)
@@ -254,7 +263,7 @@ def clear(self):
     def getIndexSourceNames(self):
         """Return sequence of names of indexed attributes"""
         try:
-            return self._indexed_attrs 
+            return self._indexed_attrs
         except:
             return [self._fieldname]
 
@@ -270,7 +279,6 @@ def getLexiconURL(self):
             return None
         else:
             return lex.absolute_url()
-            
 
 InitializeClass(ZCTextIndex)
 
@@ -314,8 +322,13 @@ def manage_addLexicon(self, id, title='', elements=[], REQUEST=None):
 LexiconQueryPerm = 'Query Vocabulary'
 LexiconMgmtPerm = 'Manage Vocabulary'
 
+
 class PLexicon(Lexicon, Acquisition.Implicit, SimpleItem):
-    """Lexicon for ZCTextIndex"""
+
+    """Lexicon for ZCTextIndex.
+    """
+
+    implements(IZCLexicon)
 
     meta_type = 'ZCTextIndex Lexicon'
 
diff --git a/interfaces.py b/interfaces.py
new file mode 100644
index 0000000..c518a11
--- /dev/null
+++ b/interfaces.py
@@ -0,0 +1,30 @@
+##############################################################################
+#
+# Copyright (c) 2005 Zope Corporation and Contributors. All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+##############################################################################
+"""ZCTextIndex z3 interfaces.
+
+$Id$
+"""
+
+from zope.interface import Interface
+
+
+class IZCTextIndex(Interface):
+
+    """Persistent text index.
+    """
+
+
+class IZCLexicon(Interface):
+
+    """Lexicon for ZCTextIndex.
+    """
diff --git a/tests/testZCTextIndex.py b/tests/testZCTextIndex.py
index 6aacc06..7dc0c36 100644
--- a/tests/testZCTextIndex.py
+++ b/tests/testZCTextIndex.py
@@ -11,14 +11,21 @@
 # FOR A PARTICULAR PURPOSE.
 #
 ##############################################################################
+"""ZCTextIndex unit tests.
+
+$Id$
+"""
+
+import unittest
+import Testing
+import Zope2
+Zope2.startup()
+
+import re
 
-from Interface.Verify import verifyClass
 import Acquisition
 from zExceptions import NotFound
 
-from Products.PluginIndexes.common.PluggableIndex import \
-     PluggableIndexInterface
-
 from Products.ZCTextIndex.ZCTextIndex import ZCTextIndex, PLexicon
 from Products.ZCTextIndex.tests import \
      testIndex, testQueryEngine, testQueryParser
@@ -32,8 +39,6 @@
 from Products.ZCTextIndex.StopDict import get_stopdict
 from Products.ZCTextIndex.ParseTree import ParseError
 
-import re
-import unittest
 
 class Indexable:
     def __init__(self, text):
@@ -250,9 +255,21 @@ class CosineIndexTests(ZCIndexTestsBase, testIndex.CosineIndexTest):
     # Gigabytes, pp. 180-188.  This test peeks into many internals of the
     # cosine indexer.
 
-    def testInterface(self):
+    def test_z2interfaces(self):
+        from Interface.Verify import verifyClass
+        from Products.PluginIndexes.common.PluggableIndex \
+                import PluggableIndexInterface
+
         verifyClass(PluggableIndexInterface, ZCTextIndex)
 
+    def test_z3interfaces(self):
+        from Products.PluginIndexes.interfaces import IPluggableIndex
+        from Products.ZCTextIndex.interfaces import IZCTextIndex
+        from zope.interface.verify import verifyClass
+
+        verifyClass(IPluggableIndex, ZCTextIndex)
+        verifyClass(IZCTextIndex, ZCTextIndex)
+
     def testRanking(self):
         self.words = ["cold", "days", "eat", "hot", "lot", "nine", "old",
                       "pease", "porridge", "pot"]
@@ -548,18 +565,28 @@ def compareSet(self, set, dict):
         dictkeys.sort()
         self.assertEqual(setkeys, dictkeys)
 
+
 class CosineQueryTests(QueryTestsBase):
     IndexFactory = CosineIndex
 
+
 class OkapiQueryTests(QueryTestsBase):
     IndexFactory = OkapiIndex
 
-############################################################################
+
+class PLexiconTests(unittest.TestCase):
+
+    def test_z3interfaces(self):
+        from Products.ZCTextIndex.interfaces import IZCLexicon
+        from zope.interface.verify import verifyClass
+
+        verifyClass(IZCLexicon, PLexicon)
+
 
 def test_suite():
     s = unittest.TestSuite()
     for klass in (CosineIndexTests, OkapiIndexTests,
-                  CosineQueryTests, OkapiQueryTests):
+                  CosineQueryTests, OkapiQueryTests, PLexiconTests):
         s.addTest(unittest.makeSuite(klass))
     return s