diff --git a/.gitignore b/.gitignore
index a4dc846..31236db 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,5 +3,3 @@ _static
 _templates
 
 TODO
-
-jsonschema/_version.py
diff --git a/jsonschema/_version.py b/jsonschema/_version.py
new file mode 100644
index 0000000..2525dd0
--- /dev/null
+++ b/jsonschema/_version.py
@@ -0,0 +1,5 @@
+
+# This file is automatically generated by setup.py.
+__version__ = '2.3.0.post128'
+__sha__ = 'g2fda689'
+__revision__ = 'g2fda689'
diff --git a/tox.ini b/tox.ini
index 7365f31..5fc1207 100644
--- a/tox.ini
+++ b/tox.ini
@@ -7,14 +7,17 @@ changedir = {envtmpdir}
 setenv =
     JSON_SCHEMA_TEST_SUITE = {toxinidir}/json
 commands =
-    green [] jsonschema
+    py26: trial [] jsonschema
+    py{27,34,py,py3}: green [] jsonschema
+
     {envpython} -m doctest {toxinidir}/README.rst
     py{26,27,34}: sphinx-build -b doctest {toxinidir}/docs {envtmpdir}/html
 deps =
-    green
-
     -e{toxinidir}[format]
 
+    py26: twisted
+    py{27,34,py,py3}: green
+
     py26: unittest2
     py{26,27,py,py3}: mock
 
diff --git a/version.txt b/version.txt
new file mode 100644
index 0000000..6baff11
--- /dev/null
+++ b/version.txt
@@ -0,0 +1 @@
+v2.3.0-128-g2fda689
\ No newline at end of file