got tox to run 2to3 on tests before running them with Python 3.x

tests/test_common.py

@@ -35,18 +35,16 @@ class TestGroupMatches(unittest.TestCase):
         )
 
 
-import six
-
 class TestSearchExact(unittest.TestCase):
     def search(self, sequence, subsequence):
         return list(search_exact(sequence, subsequence))
 
     def test_bytes(self):
-        text = six.b('abc')
+        text = 'abc'
         self.assertEqual(self.search(text, text), [0])
 
     def test_unicode(self):
-        text = six.u('abc')
+        text = u'abc'
         self.assertEqual(self.search(text, text), [0])
 
     def test_biopython_Seq(self):

tox.ini

@@ -2,12 +2,13 @@
 envlist = py26, py27, py31, py32, py33
 
 [testenv]
-setenv =
-    PYTHONPATH = {toxinidir}:{toxinidir}/searchtml
 commands = python setup.py test
 deps =
     -r{toxinidir}/requirements.txt
     -r{toxinidir}/test_requirements.txt
+whitelist_externals =
+    rm
+    2to3
 
 [testenv:py26]
 deps =
@@ -22,17 +23,32 @@ deps =
     biopython
 
 [testenv:py31]
+changedir = {toxworkdir}
+commands =
+    2to3 -n -W --output-dir {envtmpdir}/tests3 {toxinidir}/tests
+    {envpython} -m unittest2 discover {envtmpdir}/tests3
+    rm -rf {envtmpdir}/tests3
 deps =
     unittest2py3k
     mock
     {[testenv]deps}
 
 [testenv:py32]
+changedir = {toxworkdir}
+commands =
+    2to3 -n -W --output-dir {envtmpdir}/tests3 {toxinidir}/tests
+    {envpython} -m unittest discover {envtmpdir}/tests3
+    rm -rf {envtmpdir}/tests3
 deps =
     mock
     {[testenv]deps}
 
 [testenv:py33]
+changedir = {toxworkdir}
+commands =
+    2to3 -n -W --output-dir {envtmpdir}/tests3 {toxinidir}/tests
+    {envpython} -m unittest discover {envtmpdir}/tests3
+    rm -rf {envtmpdir}/tests3
 deps =
     {[testenv]deps}
     biopython