[admin] Ensure preview button is present

Author: nemesifier

README.rst

@@ -72,7 +72,7 @@ If you want to contribute, install your cloned fork:
 Setup (integrate in an existing django project)
 -----------------------------------------------
 
-``INSTALLED_APPS`` in ``settings.py`` should look like the following:
+``INSTALLED_APPS`` in ``settings.py`` should look like the following (ordering is important):
 
 .. code-block:: python
 
@@ -82,9 +82,6 @@ Setup (integrate in an existing django project)
         'django.contrib.sessions',
         'django.contrib.messages',
         'django.contrib.staticfiles',
-        # admin
-        'django_netjsonconfig.admin_theme',
-        'django.contrib.admin',
         # all-auth
         'django.contrib.sites',
         'allauth',
@@ -95,6 +92,9 @@ Setup (integrate in an existing django project)
         'openwisp_users',
         'openwisp_controller.pki',
         'openwisp_controller.config',
+        # admin
+        'django_netjsonconfig.admin_theme',
+        'django.contrib.admin',
         # other dependencies
         'sortedm2m',
         'reversion',

openwisp_controller/config/tests/test_admin.py

@@ -94,6 +94,27 @@ def test_preview_config(self):
         self.assertContains(response, 'eth0')
         self.assertContains(response, 'dhcp')
 
+    def test_config_preview_button(self):
+        config = self._create_config(organization=self._create_org())
+        path = reverse('admin:config_config_change', args=[config.pk])
+        self._login()
+        response = self.client.get(path)
+        self.assertIn('Preview', str(response.content))
+
+    def test_template_preview_button(self):
+        t = self._create_template(organization=self._create_org())
+        path = reverse('admin:config_template_change', args=[t.pk])
+        self._login()
+        response = self.client.get(path)
+        self.assertIn('Preview', str(response.content))
+
+    def test_vpn_preview_button(self):
+        v = self._create_vpn(organization=self._create_org())
+        path = reverse('admin:config_vpn_change', args=[v.pk])
+        self._login()
+        response = self.client.get(path)
+        self.assertIn('Preview', str(response.content))
+
     def _create_multitenancy_test_env(self, vpn=False):
         org1 = self._create_org(name='test1org')
         org2 = self._create_org(name='test2org')

tests/settings.py

@@ -21,9 +21,6 @@
     'django.contrib.sessions',
     'django.contrib.messages',
     'django.contrib.staticfiles',
-    # admin
-    'django_netjsonconfig.admin_theme',
-    'django.contrib.admin',
     # all-auth
     'django.contrib.sites',
     'allauth',
@@ -34,6 +31,9 @@
     'openwisp_users',
     'openwisp_controller.pki',
     'openwisp_controller.config',
+    # admin
+    'django_netjsonconfig.admin_theme',
+    'django.contrib.admin',
     # other dependencies
     'sortedm2m',
     'reversion',