admin: fixed zero division error with domain quota.

see #1166

modoboa/admin/tests/test_domain.py

@@ -244,11 +244,19 @@ class DomainTestCase(ModoTestCase):
         self.assertEqual(response.status_code, 200)
         self.assertIn("Summary", response.content.decode())
         self.assertIn("Administrators", response.content.decode())
+        self.assertIn("Usage", response.content.decode())
         self.assertNotIn("Resources usage", response.content.decode())
         self.set_global_parameter("enable_domain_limits", True, app="limits")
         response = self.client.get(url)
         self.assertIn("Resources usage", response.content.decode())
 
+        # Try a domain with no quota
+        domain = Domain.objects.filter(quota=0).first()
+        url = reverse("admin:domain_detail", args=[domain.pk])
+        response = self.client.get(url)
+        self.assertEqual(response.status_code, 200)
+        self.assertNotIn("Usage", response.content.decode())
+
     def test_statitics_widget(self):
         """Test statistics display in dashboard."""
         url = reverse("core:dashboard")

modoboa/admin/views/domain.py

@@ -176,20 +176,23 @@ class DomainDetailView(
         result = signals.extra_domain_dashboard_widgets.send(
             self.__class__, user=self.request.user, domain=self.object)
         parameters = self.request.localconfig.parameters
-        used_quota = int(
-            Quota.objects.get_domain_usage(self.object) / 1048576)
-        used_quota_in_percent = int(
-            used_quota / float(self.object.quota) * 100)
-        allocated_quota = (
-            self.object.allocated_quota_in_percent - used_quota_in_percent)
         context.update({
             "templates": {"left": [], "right": []},
             "enable_mx_checks": parameters.get_value("enable_mx_checks"),
             "enable_dnsbl_checks": parameters.get_value("enable_dnsbl_checks"),
-            "used_quota": used_quota,
-            "used_quota_in_percent": used_quota_in_percent,
-            "allocated_quota": allocated_quota
         })
+        if self.object.quota:
+            used_quota = int(
+                Quota.objects.get_domain_usage(self.object) / 1048576)
+            used_quota_in_percent = int(
+                used_quota / float(self.object.quota) * 100)
+            allocated_quota = (
+                self.object.allocated_quota_in_percent - used_quota_in_percent)
+            context.update({
+                "used_quota": used_quota,
+                "used_quota_in_percent": used_quota_in_percent,
+                "allocated_quota": allocated_quota
+            })
         for receiver, widgets in result:
             for widget in widgets:
                 context["templates"][widget["column"]].append(