diff --git a/setup.py b/setup.py
index 95eb06e..927cd2c 100644
--- a/setup.py
+++ b/setup.py
@@ -18,7 +18,7 @@
     "flake8>=3.8.3",
 ]
 
-extras["test"] = ["pytest"]
+extras["test"] = ["pytest", "gymnasium[classic-control"]
 
 extras["dev"] = extras["quality"] + extras["test"]