diff --git a/tests/unit/test_dagascii.py b/tests/unit/test_dagascii.py
index 7ef20bd85..6e8ad4a10 100644
--- a/tests/unit/test_dagascii.py
+++ b/tests/unit/test_dagascii.py
@@ -1,4 +1,3 @@
-import mock
 import os
 
 from dvc import dagascii
@@ -21,8 +20,9 @@ def test_plainpager_returned_when_less_missing(mocker):
     assert pager.__name__ == "plainpager"
 
 
-def test_tempfilepager_returned_when_var_defined(mocker):
-    mocker.patch.dict(os.environ, {"DVC_PAGER": dagascii.DEFAULT_PAGER})
+def test_tempfilepager_returned_when_var_defined(monkeypatch):
+    monkeypatch.setenv(DVC_PAGER, dagascii.DEFAULT_PAGER)
+
     pager = dagascii.find_pager()
 
     assert pager.cmd == dagascii.DEFAULT_PAGER