diff --git a/tests.py b/tests.py
index d26b364aae2bd0e81f74b3f7070756fcd65cdc73..685ce134653ab52da9b67c82d52e6d786862b8ef 100644
--- a/tests.py
+++ b/tests.py
@@ -315,9 +315,7 @@ def test_install_environment_zlib():
     assert os.path.exists(release_base_dir / microarch)
     assert os.path.exists(release_base_dir / microarch / "lmod")
     # assert that lmod/module-index.yaml contains zlib
-    with open(
-        release_base_dir / microarch / "lmod" / "module-index.yaml", "r"
-    ) as f:
+    with open(release_base_dir / microarch / "lmod" / "module-index.yaml", "r") as f:
         lines = f.read()
         assert "zlib" in lines