diff --git a/tox.ini b/tox.ini
index 941dd41b..11eee8bb 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,6 +4,7 @@ envlist=
 
 [testenv]
 deps=
+    pytest
     # TODO: Hotfix, remove when fixed https://github.com/aio-libs/aiohttp/issues/5107
     typing_extensions
     httpx
@@ -37,6 +38,7 @@ commands=
 
 [testenv:2.7]
 deps=
+    pytest
 extras=
     yaml
     flask
@@ -45,6 +47,7 @@ python_files = test_*_py2_py3.py
 
 [testenv:3.5]
 deps=
+    pytest
     contextvars
 extras=
     yaml
@@ -53,6 +56,7 @@ python_files = test_*_py3.py
 
 [testenv:pypy2]
 deps=
+    pytest
 extras=
     yaml
     flask
@@ -60,6 +64,7 @@ python_files = test_*_py2_py3.py
 
 [testenv:pypy3]
 deps=
+    pytest
     httpx
     fastapi
     boto3