Prevent IndexError in MethodForm when method registry is empty (fixes #742)

tests/test_forms.py

@@ -1,10 +1,17 @@
 from django.test import TestCase
 
-from two_factor.forms import AuthenticationTokenForm
+from tests.utils import method_registry
+from two_factor.forms import AuthenticationTokenForm, MethodForm
 
 
 class FormTests(TestCase):
     def test_auth_token_form(self):
         form = AuthenticationTokenForm(None, None, data={'otp_token': '005428'})
         self.assertTrue(form.is_valid())
         self.assertEqual(form.cleaned_data['otp_token'], '005428')
+
+    @method_registry([])
+    def test_method_form_empty_registry(self):
+        form = MethodForm()
+        self.assertEqual(form.fields['method'].choices, [])
+        self.assertIsNone(form.fields['method'].initial)

tests/test_views_setup.py

@@ -22,6 +22,13 @@ def test_form(self):
         self.assertContains(response, 'Follow the steps in this wizard to '
                                       'enable two-factor')
 
+    @method_registry([])
+    def test_setup_no_methods_available(self):
+        response = self.client.post(
+            reverse('two_factor:setup'),
+            data={'setup_view-current_step': 'welcome'})
+        self.assertEqual(response.status_code, 200)
+
     @method_registry(['generator'])
     def test_setup_only_generator_available(self):
         response = self.client.post(

two_factor/forms.py

@@ -23,7 +23,8 @@ def __init__(self, **kwargs):
         method.choices = [
             (m.code, m.verbose_name) for m in registry.get_methods()
         ]
-        method.initial = method.choices[0][0]
+        if method.choices:
+            method.initial = method.choices[0][0]
 
 
 class DeviceValidationForm(forms.Form):