diff --git a/circle.yml b/circle.yml
index 931da97..4ff74de 100644
--- a/circle.yml
+++ b/circle.yml
@@ -10,5 +10,8 @@ dependencies:
     - pip install tox
 
 test:
+  pre:
+    - pyenv versions
+    - pyenv global 2.7.10 3.4.3 3.5 pypy-2.5.0
   override:
     - tox -e circleci_27,circleci_34,circleci_35,circleci_pypy