pytest 3.3.0 has an issue with parametrized null bytes again (#4026)

diff --git a/setup.py b/setup.py
index 2f32c76..b9186a8 100644
--- a/setup.py
+++ b/setup.py
@@ -55,7 +55,7 @@
     setup_requirements.append("cffi>=1.7")
 
 test_requirements = [
-    "pytest>=3.2.1",
+    "pytest>=3.2.1,!=3.3.0",
     "pretend",
     "iso8601",
     "pytz",