Report error on creating release component for missing release

The ReleaseField is refactored to be based on SlugRelatedField which
provides error handling consistent with rest of the API.

There is now a test for creating a release component on a non-existing
release.

JIRA: PDC-868

pdc/apps/component/serializers.py

@@ -19,7 +19,6 @@
 from pdc.apps.common.serializers import DynamicFieldsSerializerMixin, LabelSerializer, StrictSerializerMixin
 from pdc.apps.common.fields import ChoiceSlugField
 from pdc.apps.release.models import Release
-from pdc.apps.release.serializers import ReleaseSerializer
 from .models import (GlobalComponent,
                      RoleContact,
                      ReleaseComponent,
@@ -300,20 +299,17 @@ class Meta:
         fields = ('id', 'name', 'parent_component', 'subcomponents')
 
 
-class ReleaseField(serializers.Field):
-    def to_representation(self, value):
-        ret = {}
-        serializer = ReleaseSerializer(value)
-        ret.setdefault('release_id', serializer.data['release_id'])
-        ret.setdefault('active', serializer.data['active'])
-        return ret
+class ReleaseField(serializers.SlugRelatedField):
+    def __init__(self, **kwargs):
+        super(ReleaseField, self).__init__(slug_field='release_id',
+                                           queryset=Release.objects.all(),
+                                           **kwargs)
 
-    def to_internal_value(self, data):
-        try:
-            rel = Release.objects.get(release_id=data)
-        except Release.DoesNotExist:
-            raise Exception("Release with ID %s doesn't exist" % data)
-        return rel
+    def to_representation(self, value):
+        return {
+            'release_id': value.release_id,
+            'active': value.active
+        }
 
 
 class ReleaseComponentSerializer(DynamicFieldsSerializerMixin,

pdc/apps/component/tests.py

@@ -841,6 +841,17 @@ def test_create_release_component(self):
         self.assertEqual(sorted(response.data), sorted(data))
         self.assertNumChanges([1])
 
+    def test_create_release_component_for_non_existing_release(self):
+        url = reverse('releasecomponent-list')
+        data = {'release': 'hello-1.0',
+                'global_component': 'python',
+                'name': 'python26',
+                'brew_package': 'python-pdc'}
+        response = self.client.post(url, data, format='json')
+        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
+        self.assertEqual(response.data, {'release': ['Object with release_id=hello-1.0 does not exist.']})
+        self.assertNumChanges([])
+
     def test_create_release_component_with_type(self):
         url = reverse('releasecomponent-list')
         data = {'release': 'release-1.0', 'global_component': 'python', 'name': 'python26',