Don't gpg sign during test

tests/check_added_large_files_test.py

diff --git a/tests/check_added_large_files_test.py b/tests/check_added_large_files_test.py
index ce15f5c..4a84463 100644
--- a/tests/check_added_large_files_test.py
+++ b/tests/check_added_large_files_test.py
@@ -81,12 +81,7 @@
     with temp_git_dir.as_cwd():
         # Work around https://github.com/github/git-lfs/issues/913
         cmd_output(
-            'git',
-            'commit',
-            '--no-gpg-sign',
-            '--allow-empty',
-            '-m',
-            'foo',
+            'git', 'commit', '--no-gpg-sign', '--allow-empty', '-m', 'foo',
         )
         cmd_output('git', 'lfs', 'install')
         temp_git_dir.join('f.py').write('a' * 10000)

tests/forbid_new_submodules_test.py

diff --git a/tests/forbid_new_submodules_test.py b/tests/forbid_new_submodules_test.py
index 1750e00..fb37862 100644
--- a/tests/forbid_new_submodules_test.py
+++ b/tests/forbid_new_submodules_test.py
@@ -10,10 +10,14 @@
 def git_dir_with_git_dir(tmpdir):
     with tmpdir.as_cwd():
         cmd_output('git', 'init', '.')
-        cmd_output('git', 'commit', '-m', 'init', '--allow-empty')
+        cmd_output(
+            'git', 'commit', '-m', 'init', '--allow-empty', '--no-gpg-sign',
+        )
         cmd_output('git', 'init', 'foo')
-        with tmpdir.join('foo').as_cwd():
-            cmd_output('git', 'commit', '-m', 'init', '--allow-empty')
+        cmd_output(
+            'git', 'commit', '-m', 'init', '--allow-empty', '--no-gpg-sign',
+            cwd=tmpdir.join('foo').strpath,
+        )
         yield