Add test for utils.chdir

tests/test_utils.py

@@ -1,6 +1,8 @@
 """
 Tests for repo2docker/utils.py
 """
+import os
+from tempfile import TemporaryDirectory
 from repo2docker import utils
 import pytest
 import subprocess
@@ -34,4 +36,12 @@ def test_capture_cmd_capture_fail():
         for line in utils.execute_cmd([
             '/bin/bash', '-c', 'echo test; exit 1 '
         ], capture=True):
-            assert line == 'test\n'
+            assert line == 'test\n'
+
+
+def test_chdir():
+    with TemporaryDirectory() as d:
+        cur_cwd = os.getcwd()
+        with utils.chdir(d):
+            assert os.getcwd() == d
+        assert os.getcwd() == cur_cwd