1 files changed, 18 insertions, 1 deletions
diff --git a/tests/test_util.py b/tests/test_util.py
index 8e4fbd6b0..1ec283187 100644
--- a/tests/test_util.py
+++ b/tests/test_util.py
@@ -9,12 +9,15 @@
     :license: BSD, see LICENSE for details.
 """
 
+import os
+import tempfile
+
 import pytest
 from mock import patch
 
 from sphinx.testing.util import strip_escseq
 from sphinx.util import (
-    display_chunk, encode_uri, parselinenos, status_iterator, xmlname_checker
+    display_chunk, encode_uri, ensuredir, parselinenos, status_iterator, xmlname_checker
 )
 from sphinx.util import logging
 
@@ -34,6 +37,20 @@ def test_encode_uri():
     assert expected, encode_uri(uri)
 
 
+def test_ensuredir():
+    with tempfile.TemporaryDirectory() as tmp_path:
+        # Does not raise an exception for an existing directory.
+        ensuredir(tmp_path)
+
+        path = os.path.join(tmp_path, 'a', 'b', 'c')
+        ensuredir(path)
+        assert os.path.isdir(path)
+
+    with tempfile.NamedTemporaryFile() as tmp:
+        with pytest.raises(OSError):
+            ensuredir(tmp.name)
+
+
 def test_display_chunk():
     assert display_chunk('hello') == 'hello'
     assert display_chunk(['hello']) == 'hello'