Pin pytest in tox too
diff --git a/tox.ini b/tox.ini
index 11a0821..fcf7095 100644
--- a/tox.ini
+++ b/tox.ini
@@ -7,7 +7,7 @@
 passenv = ARCHFLAGS CFLAGS LC_ALL LDFLAGS PATH LD_LIBRARY_PATH TERM
 deps =
     coverage
-    pytest
+    pytest>=2.8.2
     cryptographyMaster: git+https://github.com/pyca/cryptography.git
 setenv =
     # Do not allow the executing environment to pollute the test environment