diff --git a/oidc_provider/management/commands/creatersakey.py b/oidc_provider/management/commands/creatersakey.py
index fb406f1..c6a5352 100644
--- a/oidc_provider/management/commands/creatersakey.py
+++ b/oidc_provider/management/commands/creatersakey.py
@@ -1,7 +1,7 @@
 from Crypto.PublicKey import RSA
 
 from django.conf import settings
-from django.core.management.base import BaseCommand, CommandError
+from django.core.management.base import BaseCommand
 
 
 class Command(BaseCommand):
@@ -11,8 +11,8 @@ class Command(BaseCommand):
         try:
             key = RSA.generate(1024)
             file_path = settings.BASE_DIR + '/OIDC_RSA_KEY.pem'
-            with open(file_path, 'w') as f:
+            with open(file_path, 'wb') as f:
                 f.write(key.exportKey('PEM'))
             self.stdout.write('RSA key successfully created at: ' + file_path)
         except Exception as e:
-            self.stdout.write('Something goes wrong: ' + e.message)
+            self.stdout.write('Something goes wrong: {0}'.format(e))
diff --git a/oidc_provider/tests/test_creatersakey_command.py b/oidc_provider/tests/test_creatersakey_command.py
new file mode 100644
index 0000000..81f676e
--- /dev/null
+++ b/oidc_provider/tests/test_creatersakey_command.py
@@ -0,0 +1,11 @@
+from django.core.management import call_command
+from django.test import TestCase, override_settings
+from django.utils.six import StringIO
+
+
+class CreateRSAKeyTest(TestCase):
+    @override_settings(BASE_DIR='/tmp')
+    def test_command_output(self):
+        out = StringIO()
+        call_command('creatersakey', stdout=out)
+        self.assertIn('RSA key successfully created', out.getvalue())