Remove dependency on plumbum
diff --git a/tests/conftest.py b/tests/conftest.py
index 157da6b..de9c2fe 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -3,11 +3,19 @@
 from __future__ import unicode_literals
 
 import pytest
-from plumbum import local
+
+from pre_commit_hooks.util import cmd_output
+from testing.util import cwd
+
+
+@pytest.yield_fixture
+def in_tmpdir(tmpdir):
+    with cwd(tmpdir.strpath):
+        yield tmpdir
 
 
 @pytest.yield_fixture
 def temp_git_dir(tmpdir):
     git_dir = tmpdir.join('gits').strpath
-    local['git']('init', git_dir)
+    cmd_output('git', 'init', git_dir)
     yield git_dir