diff --git a/tests/test_project.py b/tests/test_project.py
index e1eca14e..b948a256 100644
--- a/tests/test_project.py
+++ b/tests/test_project.py
@@ -17,7 +17,7 @@ def run(command: str, dirpath: os.PathLike) -> subprocess.CompletedProcess:
                           stdout=subprocess.PIPE,
                           stderr=subprocess.PIPE,
                           cwd=dirpath,
-                          text=True)
+                          encoding="utf-8")
 
 
 def test_pytest(cookies):