diff --git a/nbgitpuller/pull.py b/nbgitpuller/pull.py
index 2b74b4b4..dd085e64 100644
--- a/nbgitpuller/pull.py
+++ b/nbgitpuller/pull.py
@@ -16,6 +16,9 @@ def execute_cmd(cmd, **kwargs):
     yield '$ {}\n'.format(' '.join(cmd))
     kwargs['stdout'] = subprocess.PIPE
     kwargs['stderr'] = subprocess.STDOUT
+    # Explicitly set LANG=C, as `git` commandline output will be different if
+    # the user environment has a different locale set!
+    kwargs['env'] = dict(os.environ, LANG='C')
 
     proc = subprocess.Popen(cmd, **kwargs)
 
diff --git a/tests/repohelpers.py b/tests/repohelpers.py
index 9a83dfb8..dabd9762 100644
--- a/tests/repohelpers.py
+++ b/tests/repohelpers.py
@@ -18,7 +18,7 @@ def __init__(self, path=None):
 
     def __enter__(self):
         os.makedirs(self.path, exist_ok=True)
-        self.git('init', '--bare')
+        self.git('init', '--bare', '--initial-branch=master')
         return self
 
     def __exit__(self, *args):