Create email settings for new TestPlan. Fix #181

also change post_delete to pre_delete signal.

Explanation:

There is a TestPlan object and the TestPlan.email_settings
attribute points to TestPlanEmailSettings object. When we
delete the TP Django will first delete the TPES object, then
initiate TP.delete() and at the end of it send the post_delete
signal. Upon receiving of this signal the TPES object doesn't
exist anymore and trying to access it via TP.emailing property
tries to create a new TPES object pointing to the TP instance.

Because it has already been deleted from the DB MySQL integrity
check fails. The only way is to notify users about plan deletion
using a pre_delete signal because all objects are still available
in the database.

Signed-off-by: Mr. Senko <atodorov@mrsenko.com>

tcms/testplans/models.py

@@ -5,7 +5,7 @@
 from django.core.exceptions import ObjectDoesNotExist
 from django.db import models
 from django.db.models import Max
-from django.db.models.signals import post_save, post_delete, pre_save
+from django.db.models.signals import post_save, pre_delete, pre_save
 from uuslug import slugify
 
 from tcms.management.models import Version
@@ -358,14 +358,14 @@ class Meta:
 
 def _listen():
     post_save.connect(plan_watchers.on_plan_save, TestPlan)
-    post_delete.connect(plan_watchers.on_plan_delete, TestPlan)
+    pre_delete.connect(plan_watchers.on_plan_delete, TestPlan)
     pre_save.connect(plan_watchers.pre_save_clean, TestPlan)
 
 
 def _disconnect_signals():
     """ used in testing """
     post_save.disconnect(plan_watchers.on_plan_save, TestPlan)
-    post_delete.disconnect(plan_watchers.on_plan_delete, TestPlan)
+    pre_delete.disconnect(plan_watchers.on_plan_delete, TestPlan)
     pre_save.disconnect(plan_watchers.pre_save_clean, TestPlan)
 
 

tcms/testplans/views.py

@@ -126,6 +126,9 @@ def new(request, template_name='plan/new.html'):
                     for env_group in env_groups:
                         tp.add_env_group(env_group=env_group)
 
+            # create emailing settings to avoid Issue #181 on MySQL
+            tp.emailing.save()
+
             return HttpResponseRedirect(
                 reverse('tcms.testplans.views.get', args=[tp.plan_id, ])
             )