diff --git a/test/test_main.py b/test/test_main.py
index 321aba81..2a86c13b 100644
--- a/test/test_main.py
+++ b/test/test_main.py
@@ -254,19 +254,15 @@ def test_conditional_pager(monkeypatch):
     SPECIAL_COMMANDS['pager'].handler('')
 
 
-def test_reserved_space_is_integer():
+def test_reserved_space_is_integer(monkeypatch):
     """Make sure that reserved space is returned as an integer."""
     def stub_terminal_size():
         return (5, 5)
 
-    old_func = shutil.get_terminal_size
-
-    shutil.get_terminal_size = stub_terminal_size
+    monkeypatch.setattr(shutil, 'get_terminal_size', stub_terminal_size)
     mycli = MyCli()
     assert isinstance(mycli.get_reserved_space(), int)
 
-    shutil.get_terminal_size = old_func
-
 
 def test_list_dsn():
     runner = CliRunner()