[fix] Fixed dashboard template extra_config

Bug:
"openwisp_utils.admin_theme.dashboard.get_dashboard_context"
overwrote the extra_config when multiple dashboard templates
were registered.

Author: pandafy

openwisp_utils/admin_theme/dashboard.py

@@ -216,7 +216,7 @@ def get_dashboard_context(request):
         if 'js' in template_config[0]:
             js += list(template_config[0]['js'])
         if template_config[1]:
-            extra_config = template_config[1]
+            extra_config.update(template_config[1])
 
     context.update(
         {

tests/test_project/apps.py

@@ -98,7 +98,14 @@ def register_dashboard_charts(self):
                 'css': ('dashboard-test.css',),
                 'js': ('dashboard-test.js',),
             },
-            extra_config={'test_extra_config': 'dashboard-test.config'},
+            extra_config={'test_extra_config1': 'dashboard-test.config1'},
+        )
+        register_dashboard_template(
+            position=1,
+            config={
+                'template': 'dashboard_test.html',
+            },
+            extra_config={'test_extra_config2': 'dashboard-test.config2'},
         )
 
     def register_menu_groups(self):

tests/test_project/templates/dashboard_test.html

@@ -1,4 +1,7 @@
 <div style="display:none">Testing dashboard</div>
-{% if test_extra_config %}
-    <div style="display:none">{{ test_extra_config }}</div>
+{% if test_extra_config1 %}
+    <div style="display:none">{{ test_extra_config1 }}</div>
+{% endif %}
+{% if test_extra_config2 %}
+    <div style="display:none">{{ test_extra_config2 }}</div>
 {% endif %}

tests/test_project/tests/test_dashboard.py

@@ -139,7 +139,8 @@ def test_index_content(self):
         )
         self.assertContains(response, 'dashboard-test.js')
         self.assertContains(response, 'dashboard-test.css')
-        self.assertContains(response, 'dashboard-test.config')
+        self.assertContains(response, 'dashboard-test.config1')
+        self.assertContains(response, 'dashboard-test.config2')
         self.assertContains(response, 'jquery.init.js')
         self.assertContains(response, 'Operator presence in projects')
         self.assertContains(response, 'with_operator')