added django admin pages for Coupon Table

added the suggested changes by cdonge

lms/djangoapps/shoppingcart/admin.py

@@ -2,6 +2,50 @@
 Allows django admin site to add PaidCourseRegistrationAnnotations
 """
 from ratelimitbackend import admin
-from shoppingcart.models import PaidCourseRegistrationAnnotation
+from shoppingcart.models import PaidCourseRegistrationAnnotation, Coupon
+
+
+class SoftDeleteCouponAdmin(admin.ModelAdmin):
+    """
+    Admin for the Coupon table.
+    soft-delete on the coupons
+    """
+    fields = ('code', 'description', 'course_id', 'percentage_discount', 'created_by', 'created_at', 'is_active')
+    raw_id_fields = ("created_by",)
+    readonly_fields = ('created_at',)
+    actions = ['really_delete_selected']
+
+    def queryset(self, request):
+        """ Returns a QuerySet of all model instances that can be edited by the
+        admin site. This is used by changelist_view. """
+        # Default: qs = self.model._default_manager.get_active_coupons_query_set()
+        # Queryset with all the coupons including the soft-deletes: qs = self.model._default_manager.get_query_set()
+        query_string = self.model._default_manager.get_active_coupons_query_set()  # pylint: disable=W0212
+        return query_string
+
+    def get_actions(self, request):
+        actions = super(SoftDeleteCouponAdmin, self).get_actions(request)
+        del actions['delete_selected']
+        return actions
+
+    def really_delete_selected(self, request, queryset):
+        """override the default behavior of selected delete method"""
+        for obj in queryset:
+            obj.is_active = False
+            obj.save()
+
+        if queryset.count() == 1:
+            message_bit = "1 coupon entry was"
+        else:
+            message_bit = "%s coupon entries were" % queryset.count()
+        self.message_user(request, "%s successfully deleted." % message_bit)
+
+    def delete_model(self, request, obj):
+        """override the default behavior of single instance of model delete method"""
+        obj.is_active = False
+        obj.save()
+
+    really_delete_selected.short_description = "Delete s selected entries"
 
 admin.site.register(PaidCourseRegistrationAnnotation)
+admin.site.register(Coupon, SoftDeleteCouponAdmin)

lms/djangoapps/shoppingcart/models.py

@@ -337,6 +337,22 @@ class RegistrationCodeRedemption(models.Model):
     redeemed_at = models.DateTimeField(default=datetime.now(pytz.utc), null=True)
 
 
+class SoftDeleteCouponManager(models.Manager):
+    """ Use this manager to get objects that have a is_active=True """
+
+    def get_active_coupons_query_set(self):
+        """
+        filter the is_active = True Coupons only
+        """
+        return super(SoftDeleteCouponManager, self).get_query_set().filter(is_active=True)
+
+    def get_query_set(self):
+        """
+        get all the coupon objects
+        """
+        return super(SoftDeleteCouponManager, self).get_query_set()
+
+
 class Coupon(models.Model):
     """
     This table contains coupon codes
@@ -350,6 +366,11 @@ class Coupon(models.Model):
     created_at = models.DateTimeField(default=datetime.now(pytz.utc))
     is_active = models.BooleanField(default=True)
 
+    def __unicode__(self):
+        return "[Coupon] code: {} course: {}".format(self.code, self.course_id)
+
+    objects = SoftDeleteCouponManager()
+
 
 class CouponRedemption(models.Model):
     """

lms/djangoapps/shoppingcart/tests/test_views.py

 """
 Tests for Shopping Cart views
 """
+from django.http import HttpRequest
 from urlparse import urlparse
 
 from django.conf import settings
@@ -8,18 +9,21 @@ from django.test import TestCase
 from django.test.utils import override_settings
 from django.core.urlresolvers import reverse
 from django.utils.translation import ugettext as _
-from django.contrib.auth.models import Group
+from django.contrib.admin.sites import AdminSite
+from django.contrib.auth.models import Group, User
+from django.contrib.messages.storage.fallback import FallbackStorage
 
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory
 from courseware.tests.tests import TEST_DATA_MONGO_MODULESTORE
 from shoppingcart.views import _can_download_report, _get_date_from_str
 from shoppingcart.models import Order, CertificateItem, PaidCourseRegistration, Coupon
-from student.tests.factories import UserFactory
+from student.tests.factories import UserFactory, AdminFactory
 from student.models import CourseEnrollment
 from course_modes.models import CourseMode
 from edxmako.shortcuts import render_to_response
 from shoppingcart.processors import render_purchase_form_html
+from shoppingcart.admin import SoftDeleteCouponAdmin
 from mock import patch, Mock
 from shoppingcart.views import initialize_report
 from decimal import Decimal
@@ -143,6 +147,39 @@ class ShoppingCartViewsTests(ModuleStoreTestCase):
         self.assertEqual(resp.status_code, 400)
         self.assertIn("Coupon '{0}' already used.".format(self.coupon_code), resp.content)
 
+    def test_soft_delete_coupon(self):  # pylint: disable=E1101
+        self.add_coupon(self.course_key, True)
+        coupon = Coupon(code='TestCode', description='testing', course_id=self.course_key,
+                        percentage_discount=12, created_by=self.user, is_active=True)
+        coupon.save()
+        self.assertEquals(coupon.__unicode__(), '[Coupon] code: TestCode course: MITx/999/Robot_Super_Course')
+        admin = User.objects.create_user('Mark', 'admin+courses@edx.org', 'foo')
+        admin.is_staff = True
+        get_coupon = Coupon.objects.get(id=1)
+        request = HttpRequest()
+        request.user = admin
+        setattr(request, 'session', 'session')  # pylint: disable=E1101
+        messages = FallbackStorage(request)  # pylint: disable=E1101
+        setattr(request, '_messages', messages)  # pylint: disable=E1101
+        coupon_admin = SoftDeleteCouponAdmin(Coupon, AdminSite())
+        test_query_set = coupon_admin.queryset(request)
+        test_actions = coupon_admin.get_actions(request)
+        self.assertTrue('really_delete_selected' in test_actions['really_delete_selected'])
+        self.assertEqual(get_coupon.is_active, True)
+        coupon_admin.really_delete_selected(request, test_query_set)  # pylint: disable=E1101
+        for coupon in test_query_set:
+            self.assertEqual(coupon.is_active, False)
+        coupon_admin.delete_model(request, get_coupon)  # pylint: disable=E1101
+        self.assertEqual(get_coupon.is_active, False)
+
+        coupon = Coupon(code='TestCode123', description='testing123', course_id=self.course_key,
+                        percentage_discount=22, created_by=self.user, is_active=True)
+        coupon.save()
+        test_query_set = coupon_admin.queryset(request)
+        coupon_admin.really_delete_selected(request, test_query_set)  # pylint: disable=E1101
+        for coupon in test_query_set:
+            self.assertEqual(coupon.is_active, False)
+
     @patch('shoppingcart.views.log.debug')
     def test_non_existing_coupon_redemption_on_removing_item(self, debug_log):