diff --git a/tox.ini b/tox.ini
index 68a2f53..0945a6d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = {py27,py35,py36}-{c,pure},{pypy,pypy3}-pure,py27-x86,py34-x86
+envlist = {py27,py35,py36,py37}-{c,pure},{pypy,pypy3}-pure,py27-x86,py34-x86
 
 [variants:pure]
 setenv=
@@ -11,7 +11,7 @@ deps=
 
 changedir=test
 commands=
-    c,x86: python -c 'from msgpack import _packer, _unpacker'
+    c,x86: python -c 'from msgpack import _cmsgpack'
     c,x86: py.test
     pure: py.test
 
@@ -23,7 +23,7 @@ deps=
 changedir=test
 commands=
     python -c 'import sys; print(hex(sys.maxsize))'
-    python -c 'from msgpack import _packer, _unpacker'
+    python -c 'from msgpack import _cmsgpack'
     py.test
 
 [testenv:py34-x86]
@@ -34,5 +34,5 @@ deps=
 changedir=test
 commands=
     python -c 'import sys; print(hex(sys.maxsize))'
-    python -c 'from msgpack import _packer, _unpacker'
+    python -c 'from msgpack import _cmsgpack'
     py.test