Merge pull request #325 from pre-commit/use_subprocess

Use subprocess directly
diff --git a/tests/forbid_new_submodules_test.py b/tests/forbid_new_submodules_test.py
index dc64f06..523628d 100644
--- a/tests/forbid_new_submodules_test.py
+++ b/tests/forbid_new_submodules_test.py
@@ -1,7 +1,8 @@
 from __future__ import absolute_import
 
+import subprocess
+
 import pytest
-from pre_commit.util import cmd_output
 
 from pre_commit_hooks.forbid_new_submodules import main
 
@@ -9,13 +10,13 @@
 @pytest.fixture
 def git_dir_with_git_dir(tmpdir):
     with tmpdir.as_cwd():
-        cmd_output('git', 'init', '.')
-        cmd_output(
+        subprocess.check_call(('git', 'init', '.'))
+        subprocess.check_call((
             'git', 'commit', '-m', 'init', '--allow-empty', '--no-gpg-sign',
-        )
-        cmd_output('git', 'init', 'foo')
-        cmd_output(
-            'git', 'commit', '-m', 'init', '--allow-empty', '--no-gpg-sign',
+        ))
+        subprocess.check_call(('git', 'init', 'foo'))
+        subprocess.check_call(
+            ('git', 'commit', '-m', 'init', '--allow-empty', '--no-gpg-sign'),
             cwd=tmpdir.join('foo').strpath,
         )
         yield
@@ -31,7 +32,7 @@
     ),
 )
 def test_main_new_submodule(git_dir_with_git_dir, capsys, cmd):
-    cmd_output(*cmd)
+    subprocess.check_call(cmd)
     assert main() == 1
     out, _ = capsys.readouterr()
     assert out.startswith('foo: new submodule introduced\n')
@@ -39,5 +40,5 @@
 
 def test_main_no_new_submodule(git_dir_with_git_dir):
     open('test.py', 'a+').close()
-    cmd_output('git', 'add', 'test.py')
+    subprocess.check_call(('git', 'add', 'test.py'))
     assert main() == 0