diff --git a/tests/unit/test_args.py b/tests/unit/test_args.py
index d4b1a565..a1401468 100644
--- a/tests/unit/test_args.py
+++ b/tests/unit/test_args.py
@@ -14,7 +14,7 @@ def test_version(capsys):
     """
     with pytest.raises(SystemExit):
         make_r2d(['--version'])
-    assert capsys.readouterr().out == f"{__version__}\n"
+    assert capsys.readouterr().out == "{}\n".format(__version__)
 
 def test_simple():
     """