Add upvote/downvote counts to Epics API

Includes upvotes/downvotes counts on the epics API endpoints

doc/api/epics.md

@@ -79,7 +79,9 @@ Example response:
   "due_date_from_milestones": "2018-07-31",
   "created_at": "2018-07-17T13:36:22.770Z",
   "updated_at": "2018-07-18T12:22:05.239Z",
-  "labels": []
+  "labels": [],
+  "upvotes": 4,
+  "downvotes": 0
   }
 ]
 ```
@@ -129,7 +131,9 @@ Example response:
   "due_date_from_milestones": "2018-07-31",
   "created_at": "2018-07-17T13:36:22.770Z",
   "updated_at": "2018-07-18T12:22:05.239Z",
-  "labels": []
+  "labels": [],
+  "upvotes": 4,
+  "downvotes": 0
 }
 ```
 
@@ -189,7 +193,9 @@ Example response:
   "due_date_from_milestones": "2018-07-31",
   "created_at": "2018-07-17T13:36:22.770Z",
   "updated_at": "2018-07-18T12:22:05.239Z",
-  "labels": []
+  "labels": [],
+  "upvotes": 4,
+  "downvotes": 0
 }
 ```
 
@@ -251,7 +257,9 @@ Example response:
   "due_date_from_milestones": "2018-07-31",
   "created_at": "2018-07-17T13:36:22.770Z",
   "updated_at": "2018-07-18T12:22:05.239Z",
-  "labels": []
+  "labels": [],
+  "upvotes": 4,
+  "downvotes": 0
 }
 ```
 

doc/api/issues.md

@@ -107,6 +107,8 @@ Example response:
       "created_at" : "2016-01-04T15:31:51.081Z",
       "iid" : 6,
       "labels" : [],
+      "upvotes": 4,
+      "downvotes": 0,
       "user_notes_count": 1,
       "due_date": "2016-07-22",
       "web_url": "http://example.com/example/example/issues/6",
@@ -217,6 +219,8 @@ Example response:
          "name" : "Dr. Luella Kovacek"
       },
       "labels" : [],
+      "upvotes": 4,
+      "downvotes": 0,
       "id" : 41,
       "title" : "Ut commodi ullam eos dolores perferendis nihil sunt.",
       "updated_at" : "2016-01-04T15:31:46.176Z",
@@ -332,6 +336,8 @@ Example response:
          "name" : "Dr. Luella Kovacek"
       },
       "labels" : [],
+      "upvotes": 4,
+      "downvotes": 0,
       "id" : 41,
       "title" : "Ut commodi ullam eos dolores perferendis nihil sunt.",
       "updated_at" : "2016-01-04T15:31:46.176Z",
@@ -427,6 +433,8 @@ Example response:
       "name" : "Dr. Luella Kovacek"
    },
    "labels" : [],
+   "upvotes": 4,
+   "downvotes": 0,
    "id" : 41,
    "title" : "Ut commodi ullam eos dolores perferendis nihil sunt.",
    "updated_at" : "2016-01-04T15:31:46.176Z",
@@ -502,6 +510,8 @@ Example response:
    "labels" : [
       "bug"
    ],
+   "upvotes": 4,
+   "downvotes": 0,
    "author" : {
       "name" : "Alexandra Bashirian",
       "avatar_url" : null,
@@ -601,6 +611,8 @@ Example response:
    "labels" : [
       "bug"
    ],
+   "upvotes": 4,
+   "downvotes": 0,
    "id" : 85,
    "assignees" : [],
    "assignee" : null,
@@ -686,6 +698,8 @@ Example response:
   "closed_at": null,
   "closed_by": null,
   "labels": [],
+  "upvotes": 4,
+  "downvotes": 0,
   "milestone": null,
   "assignees": [{
     "name": "Miss Monserrate Beier",
@@ -769,6 +783,8 @@ Example response:
   "closed_at": null,
   "closed_by": null,
   "labels": [],
+  "upvotes": 4,
+  "downvotes": 0,
   "milestone": null,
   "assignees": [{
     "name": "Miss Monserrate Beier",
@@ -851,6 +867,8 @@ Example response:
   "created_at": "2016-04-05T21:41:45.217Z",
   "updated_at": "2016-04-07T13:02:37.905Z",
   "labels": [],
+  "upvotes": 4,
+  "downvotes": 0,
   "milestone": null,
   "assignee": {
     "name": "Edwardo Grady",

ee/changelogs/unreleased/6769-epics-votes.yml

+---
+title: Add upvote/downvote information to epics API
+merge_request: 9264
+author:
+type: added

ee/lib/api/epics.rb

@@ -9,6 +9,8 @@ module API
       authorize_epics_feature!
     end
 
+    helpers ::Gitlab::IssuableMetadata
+
     helpers do
       def authorize_epics_feature!
         forbidden! unless user_group.feature_available?(:epics)
@@ -69,9 +71,9 @@ module API
         use :pagination
       end
       get ':id/(-/)epics' do
-        epics = find_epics(group_id: user_group.id)
+        epics = paginate(find_epics(group_id: user_group.id))
 
-        present paginate(epics), with: EE::API::Entities::Epic, user: current_user
+        present epics, with: EE::API::Entities::Epic, user: current_user, epics_metadata: issuable_meta_data(epics, 'Epic')
       end
 
       desc 'Get details of an epic' do

ee/lib/ee/api/entities.rb

@@ -203,6 +203,22 @@ module EE
           # Avoids an N+1 query since labels are preloaded
           epic.labels.map(&:title).sort
         end
+        expose :upvotes do |epic, options|
+          if options[:epics_metadata]
+            # Avoids an N+1 query when metadata is included
+            options[:epics_metadata][epic.id].upvotes
+          else
+            epic.upvotes
+          end
+        end
+        expose :downvotes do |epic, options|
+          if options[:epics_metadata]
+            # Avoids an N+1 query when metadata is included
+            options[:epics_metadata][epic.id].downvotes
+          else
+            epic.downvotes
+          end
+        end
       end
 
       class EpicIssue < ::API::Entities::Issue

ee/spec/fixtures/api/schemas/public_api/v4/epic.json

@@ -24,6 +24,8 @@
         "type": "string"
       }
     },
+    "upvotes": { "type":  "integer" },
+    "downvotes": { "type":  "integer" },
     "start_date": { "type": ["date", "null"] },
     "start_date_fixed": { "type": ["date", "null"] },
     "start_date_from_milestones": { "type": ["date", "null"] },

ee/spec/fixtures/api/schemas/public_api/v4/epic_issue_link.json

@@ -28,6 +28,8 @@
         "due_date_from_milestones": { "type": ["date", "null"] },
         "due_date_is_fixed": { "type": "boolean" },
         "state": { "type": "string" },
+        "upvotes": { "type":  "integer" },
+        "downvotes": { "type":  "integer" },
         "created_at": { "type": ["string", "null"] },
         "updated_at": { "type": ["string", "null"] },
         "labels": {

ee/spec/requests/api/epics_spec.rb

@@ -142,6 +142,20 @@ describe API::Epics do
         expect_paginated_array_response([epic2.id, epic.id])
       end
 
+      it 'has upvote/downvote information' do
+        epic.create_award_emoji('thumbsup', user)
+        epic2.create_award_emoji('thumbsdown', user)
+
+        get api(url, user)
+
+        expect(response).to have_gitlab_http_status(200)
+
+        expect(json_response).to contain_exactly(
+          a_hash_including('upvotes' => 1, 'downvotes' => 0),
+          a_hash_including('upvotes' => 0, 'downvotes' => 1)
+        )
+      end
+
       it 'sorts by created_at descending by default' do
         get api(url, user)