Update and refactor random password generator

openedx/core/djangoapps/external_auth/views.py

@@ -38,6 +38,7 @@ from edxmako.shortcuts import render_to_response, render_to_string
 from openedx.core.djangoapps.external_auth.djangostore import DjangoOpenIDStore
 from openedx.core.djangoapps.external_auth.models import ExternalAuthMap
 from openedx.core.djangoapps.site_configuration.helpers import get_value
+from openedx.core.djangoapps.user_api.accounts.utils import generate_password
 from student.helpers import get_next_url_for_login_page
 from student.models import UserProfile
 from util.db import outer_atomic
@@ -78,12 +79,6 @@ def default_render_failure(request,  # pylint: disable=unused-argument
 # -----------------------------------------------------------------------------
 
 
-def generate_password(length=12, chars=string.letters + string.digits):
-    """Generate internal password for externally authenticated user"""
-    choice = random.SystemRandom().choice
-    return ''.join([choice(chars) for _i in range(length)])
-
-
 @transaction.non_atomic_requests
 @csrf_exempt
 def openid_login_complete(request,

openedx/core/djangoapps/user_api/accounts/tests/test_utils.py

@@ -16,7 +16,7 @@ from student.tests.factories import UserFactory
 from xmodule.modulestore.tests.django_utils import SharedModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory, ItemFactory
 
-from ..utils import format_social_link, validate_social_link
+from ..utils import format_social_link, validate_social_link, generate_password
 
 
 @ddt.ddt
@@ -135,3 +135,29 @@ class CompletionUtilsTestCase(SharedModuleStoreTestCase, CompletionWaffleTestMix
             )
         )
         self.assertEqual(empty_block_url, None)
+
+
+class GeneratePasswordTest(TestCase):
+    """Tests formation of randomly generated passwords."""
+
+    def test_default_args(self):
+        password = generate_password()
+        self.assertEqual(12, len(password))
+        self.assertTrue(any(c.isdigit for c in password))
+        self.assertTrue(any(c.isalpha for c in password))
+
+    def test_length(self):
+        length = 25
+        self.assertEqual(length, len(generate_password(length=length)))
+
+    def test_chars(self):
+        char = '!'
+        password = generate_password(length=12, chars=(char,))
+
+        self.assertTrue(any(c.isdigit for c in password))
+        self.assertTrue(any(c.isalpha for c in password))
+        self.assertEqual(char * 10, password[2:])
+
+    def test_min_length(self):
+        with self.assertRaises(ValueError):
+            generate_password(length=7)

openedx/core/djangoapps/user_api/accounts/utils.py

@@ -1,7 +1,9 @@
 """
 Utility methods for the account settings.
 """
+import random
 import re
+import string
 from urlparse import urlparse
 
 from django.conf import settings
@@ -176,3 +178,17 @@ def retrieve_last_sitewide_block_completed(username):
         course_key=text_type(item.location.course_key),
         location=text_type(item.location),
     )
+
+
+def generate_password(length=12, chars=string.letters + string.digits):
+    """Generate a valid random password"""
+    if length < 8:
+        raise ValueError("password must be at least 8 characters")
+
+    choice = random.SystemRandom().choice
+
+    password = ''
+    password += choice(string.digits)
+    password += choice(string.letters)
+    password += ''.join([choice(chars) for _i in xrange(length - 2)])
+    return password