Show blank screen instead of logout message for Enterprise SSO flow

Changes to show blank screen instead of logout message for Enterprise SSO flow. It confuses learner when they are already signed in and access their course from B2B site.
ENT-1688

Fixed pep8 quality violation

use testserver as HOST instead of edx.org

assert enterprise app is enabled

added logging

Print different values

Reload django url config

assert all quote operations to see how they work on jenkins

debug url resolved values

login user in setup

added log to debug test on jenkins

Using UrlResetMixin

Using regex instead of resolve

Fixed quality violation

Fixed pylint quality violations

Fixed target interpolation syntax

Added developer's comment

lms/templates/logout.html

@@ -5,14 +5,31 @@
 {% block title %}{% trans "Signed Out" as tmsg %}{{ tmsg | force_escape }} | {{ block.super }}{% endblock %}
 
 {% block body %}
-    <h1>{% trans "You have signed out." as tmsg %}{{ tmsg | force_escape }}</h1>
+    {% if enterprise_target %}
+        {% comment %}
+            For enterprise SSO flow we intentionally drop learner's session.
+            We are showing this signin message instead of logout message
+            to avoid any confusion for learner in that case.
+        {% endcomment %}
+        <h1>{% trans "We are signing you in." as tmsg %}{{ tmsg | force_escape }}</h1>
 
-    <p style="text-align: center; margin-bottom: 20px;">
-        {% blocktrans trimmed asvar signout_msg1 %}
-          If you are not redirected within 5 seconds, {start_anchor}click here to go to the home page{end_anchor}.
-        {% endblocktrans %}
-        {% interpolate_html signout_msg1 start_anchor='<a href="{{ target }}">'|safe end_anchor='</a>'|safe %}
-    </p>
+        <p style="text-align: center; margin-bottom: 20px;">
+            {% filter force_escape %}
+            {% blocktrans %}
+              This may take a minute. If you are not redirected, go to the home page.
+            {% endblocktrans %}
+            {% endfilter %}
+        </p>
+    {% else %}
+        <h1>{% trans "You have signed out." as tmsg %}{{ tmsg | force_escape }}</h1>
+
+        <p style="text-align: center; margin-bottom: 20px;">
+            {% blocktrans trimmed asvar signout_msg1 %}
+              If you are not redirected within 5 seconds, {start_anchor}click here to go to the home page{end_anchor}.
+            {% endblocktrans %}
+            {% interpolate_html signout_msg1 start_anchor='<a href="'|add:target|add:'">'|safe end_anchor='</a>'|safe %}
+        </p>
+    {% endif %}
 
     <div id="iframeContainer" style="visibility: hidden" data-redirect-url="{{ target }}">
         {% for uri in logout_uris %}

openedx/core/djangoapps/user_authn/views/logout.py

 """ Views related to logout. """
 from __future__ import absolute_import
 
+import re
+
 import edx_oauth2_provider
 import six.moves.urllib.parse as parse  # pylint: disable=import-error
 from django.conf import settings
@@ -98,6 +100,15 @@ class LogoutView(TemplateView):
         new_query_string = urlencode(query_params, doseq=True)
         return urlunsplit((scheme, netloc, path, new_query_string, fragment))
 
+    def _is_enterprise_target(self, url):
+        """
+        Check if url belongs to enterprise app
+
+        Args: url(str): url path
+        """
+        unquoted_url = parse.unquote_plus(parse.quote(url))
+        return bool(re.match(r'^/enterprise/[a-z0-9\-]+/course', unquoted_url))
+
     def get_context_data(self, **kwargs):
         context = super(LogoutView, self).get_context_data(**kwargs)
 
@@ -122,9 +133,11 @@ class LogoutView(TemplateView):
             if not referrer or (referrer and not uri.startswith(referrer)):
                 logout_uris.append(self._build_logout_url(uri))
 
+        target = self.target
         context.update({
-            'target': self.target,
+            'target': target,
             'logout_uris': logout_uris,
+            'enterprise_target': self._is_enterprise_target(target),
         })
 
         return context

openedx/features/enterprise_support/tests/test_logout.py

+"""
+Tests for logout for enterprise flow
+"""
+from __future__ import absolute_import
+
+import ddt
+import mock
+
+from django.test.utils import override_settings
+from django.urls import reverse
+
+from openedx.core.djangolib.testing.utils import CacheIsolationTestCase, skip_unless_lms
+from openedx.features.enterprise_support.api import enterprise_enabled
+from openedx.features.enterprise_support.tests import (
+    FAKE_ENTERPRISE_CUSTOMER,
+    FEATURES_WITH_ENTERPRISE_ENABLED,
+    factories
+)
+from openedx.features.enterprise_support.tests.mixins.enterprise import EnterpriseServiceMockMixin
+from student.tests.factories import UserFactory
+from util.testing import UrlResetMixin
+
+
+@ddt.ddt
+@override_settings(FEATURES=FEATURES_WITH_ENTERPRISE_ENABLED)
+@skip_unless_lms
+class EnterpriseLogoutTests(EnterpriseServiceMockMixin, CacheIsolationTestCase, UrlResetMixin):
+    """ Tests for the enterprise logout functionality. """
+
+    def setUp(self):
+        super(EnterpriseLogoutTests, self).setUp()
+        self.user = UserFactory()
+
+        self.enterprise_customer = FAKE_ENTERPRISE_CUSTOMER
+        self.enterprise_learner = factories.EnterpriseCustomerUserFactory(user_id=self.user.id)
+
+        self.client.login(username=self.user.username, password='test')
+        patcher = mock.patch('openedx.features.enterprise_support.api.enterprise_customer_from_api')
+        self.mock_enterprise_customer_from_api = patcher.start()
+        self.mock_enterprise_customer_from_api.return_value = self.enterprise_customer
+        self.addCleanup(patcher.stop)
+
+    @ddt.data(
+        ('https%3A%2F%2Ftest.edx.org%2Fcourses', False),
+        ('/courses/course-v1:ARTS+D1+2018_T/course/', False),
+        ('invalid-url', False),
+        ('/enterprise/c5dad9a7-741c-4841-868f-850aca3ff848/course/Microsoft+DAT206x/enroll/', True),
+        ('%2Fenterprise%2Fc5dad9a7-741c-4841-868f-850aca3ff848%2Fcourse%2FMicrosoft%2BDAT206x%2Fenroll%2F', True),
+    )
+    @ddt.unpack
+    def test_logout_enterprise_target(self, redirect_url, enterprise_target):
+        url = '{logout_path}?redirect_url={redirect_url}'.format(
+            logout_path=reverse('logout'),
+            redirect_url=redirect_url
+        )
+        self.assertTrue(enterprise_enabled())
+        response = self.client.get(url, HTTP_HOST='testserver')
+        expected = {
+            'enterprise_target': enterprise_target,
+        }
+        self.assertDictContainsSubset(expected, response.context_data)
+
+        if enterprise_target:
+            self.assertContains(response, 'We are signing you in.')