Add task count and completed count to responses of Issue and MR

Add spec for task_completion_status

Add test cases for task_completion_status result

Extracted shared samples

Add new spec file for task completion status response

Fix style errors

Add changelog entry

Changed samples to Hashes

Remove test for successful request

Remove not nil expectation

Add task_completion_status to api documentation for issues

Add task_completion_status to api documentation for merge_requests

Refactor spec so it just requests one specific item

Add task_completion_status to Taskable

Simplified task completion status in entities

Refactor spec so it separates status code check and content check

Fix spec description text and field name

2 files changed, 105 insertions, 21 deletions

diff --git a/doc/api/issues.md b/doc/api/issues.md
index 4fb3626f637..0d96cfa1b21 100644
--- a/doc/api/issues.md
+++ b/doc/api/issues.md
@@ -135,7 +135,11 @@ Example response:
          "award_emoji":"http://example.com/api/v4/projects/1/issues/76/award_emoji",
          "project":"http://example.com/api/v4/projects/1"
       },
-      "subscribed": false
+      "subscribed": false,
+      "task_completion_status":{
+         "count":0,
+         "completed_count":0
+      }
    }
 ]
 ```
@@ -265,7 +269,11 @@ Example response:
          "award_emoji":"http://example.com/api/v4/projects/4/issues/41/award_emoji",
          "project":"http://example.com/api/v4/projects/4"
       },
-      "subscribed": false
+      "subscribed": false,
+      "task_completion_status":{
+         "count":0,
+         "completed_count":0
+      }
    }
 ]
 ```
@@ -403,7 +411,11 @@ Example response:
          "award_emoji":"http://example.com/api/v4/projects/4/issues/41/award_emoji",
          "project":"http://example.com/api/v4/projects/4"
       },
-      "subscribed": false
+      "subscribed": false,
+      "task_completion_status":{
+         "count":0,
+         "completed_count":0
+      }
    }
 ]
 ```
@@ -500,6 +512,10 @@ Example response:
       "notes": "http://example.com/api/v4/projects/1/issues/2/notes",
       "award_emoji": "http://example.com/api/v4/projects/1/issues/2/award_emoji",
       "project": "http://example.com/api/v4/projects/1"
+   },
+   "task_completion_status":{
+      "count":0,
+      "completed_count":0
    }
 }
 ```
@@ -583,6 +599,10 @@ Example response:
       "notes": "http://example.com/api/v4/projects/1/issues/2/notes",
       "award_emoji": "http://example.com/api/v4/projects/1/issues/2/award_emoji",
       "project": "http://example.com/api/v4/projects/1"
+   },
+   "task_completion_status":{
+      "count":0,
+      "completed_count":0
    }
 }
 ```
@@ -674,6 +694,10 @@ Example response:
       "notes": "http://example.com/api/v4/projects/1/issues/2/notes",
       "award_emoji": "http://example.com/api/v4/projects/1/issues/2/award_emoji",
       "project": "http://example.com/api/v4/projects/1"
+   },
+   "task_completion_status":{
+      "count":0,
+      "completed_count":0
    }
 }
 ```
@@ -780,6 +804,10 @@ Example response:
     "notes": "http://example.com/api/v4/projects/1/issues/2/notes",
     "award_emoji": "http://example.com/api/v4/projects/1/issues/2/award_emoji",
     "project": "http://example.com/api/v4/projects/1"
+  },
+  "task_completion_status":{
+     "count":0,
+     "completed_count":0
   }
 }
 ```
@@ -865,6 +893,10 @@ Example response:
     "notes": "http://example.com/api/v4/projects/1/issues/2/notes",
     "award_emoji": "http://example.com/api/v4/projects/1/issues/2/award_emoji",
     "project": "http://example.com/api/v4/projects/1"
+  },
+  "task_completion_status":{
+     "count":0,
+     "completed_count":0
   }
 }
 ```
@@ -931,7 +963,11 @@ Example response:
   "due_date": null,
   "web_url": "http://example.com/example/example/issues/12",
   "confidential": false,
-  "discussion_locked": false
+  "discussion_locked": false,
+  "task_completion_status":{
+     "count":0,
+     "completed_count":0
+  }
 }
 ```
 
@@ -1029,7 +1065,11 @@ Example response:
     "due_date": null,
     "web_url": "http://example.com/example/example/issues/110",
     "confidential": false,
-    "discussion_locked": false
+    "discussion_locked": false,
+    "task_completion_status":{
+       "count":0,
+       "completed_count":0
+    }
   },
   "target_url": "https://gitlab.example.com/gitlab-org/gitlab-ci/issues/10",
   "body": "Vel voluptas atque dicta mollitia adipisci qui at.",
diff --git a/doc/api/merge_requests.md b/doc/api/merge_requests.md
index 9529a9ec1f5..96a956ad03a 100644
--- a/doc/api/merge_requests.md
+++ b/doc/api/merge_requests.md
@@ -138,7 +138,11 @@ Parameters:
       "human_time_estimate": null,
       "human_total_time_spent": null
     },
-    "squash": false
+    "squash": false,
+    "task_completion_status":{
+      "count":0,
+      "completed_count":0
+    }
   }
 ]
 ```
@@ -280,7 +284,11 @@ Parameters:
       "human_time_estimate": null,
       "human_total_time_spent": null
     },
-    "squash": false
+    "squash": false,
+    "task_completion_status":{
+      "count":0,
+      "completed_count":0
+    }
   }
 ]
 ```
@@ -410,7 +418,11 @@ Parameters:
       "human_time_estimate": null,
       "human_total_time_spent": null
     },
-    "squash": false
+    "squash": false,
+    "task_completion_status":{
+      "count":0,
+      "completed_count":0
+    }
   }
 ]
 ```
@@ -545,7 +557,11 @@ Parameters:
     "start_sha": "c380d3acebd181f13629a25d2e2acca46ffe1e00"
   },
   "diverged_commits_count": 2,
-  "rebase_in_progress": false
+  "rebase_in_progress": false,
+  "task_completion_status":{
+    "count":0,
+    "completed_count":0
+  }
 }
 ```
 
@@ -579,7 +595,7 @@ Parameters:
     "state": "active",
     "avatar_url": "http://www.gravatar.com/avatar/10fc7f102be8de7657fb4d80898bbfe3?s=80&d=identicon",
     "web_url": "http://localhost/user2"
-  },
+  }
 ]
 ```
 
@@ -702,7 +718,11 @@ Parameters:
     "total_time_spent": 0,
     "human_time_estimate": null,
     "human_total_time_spent": null
-  }
+  },
+  "task_completion_status":{
+    "count":0,
+    "completed_count":0
+  },
   "changes": [
     {
     "old_path": "VERSION",
@@ -865,7 +885,11 @@ POST /projects/:id/merge_requests
     "head_sha": "2be7ddb704c7b6b83732fdd5b9f09d5a397b5f8f",
     "start_sha": "c380d3acebd181f13629a25d2e2acca46ffe1e00"
   },
-  "diverged_commits_count": 2
+  "diverged_commits_count": 2,
+  "task_completion_status":{
+    "count":0,
+    "completed_count":0
+  }
 }
 ```
 
@@ -1002,7 +1026,11 @@ Must include at least one non-required attribute from above.
     "head_sha": "2be7ddb704c7b6b83732fdd5b9f09d5a397b5f8f",
     "start_sha": "c380d3acebd181f13629a25d2e2acca46ffe1e00"
   },
-  "diverged_commits_count": 2
+  "diverged_commits_count": 2,
+  "task_completion_status":{
+    "count":0,
+    "completed_count":0
+  }
 }
 ```
 
@@ -1155,13 +1183,17 @@ Parameters:
     "head_sha": "2be7ddb704c7b6b83732fdd5b9f09d5a397b5f8f",
     "start_sha": "c380d3acebd181f13629a25d2e2acca46ffe1e00"
   },
-  "diverged_commits_count": 2
+  "diverged_commits_count": 2,
+  "task_completion_status":{
+    "count":0,
+    "completed_count":0
+  }
 }
 ```
 
 ## Returns the up to date merge-ref HEAD commit
 
-Merge the changes between the merge request source and target branches into `refs/merge-requests/:iid/merge` 
+Merge the changes between the merge request source and target branches into `refs/merge-requests/:iid/merge`
 ref, of the target project repository, if possible. This ref will have the state the target branch would have if
 a regular merge action was taken.
 
@@ -1309,7 +1341,11 @@ Parameters:
     "head_sha": "2be7ddb704c7b6b83732fdd5b9f09d5a397b5f8f",
     "start_sha": "c380d3acebd181f13629a25d2e2acca46ffe1e00"
   },
-  "diverged_commits_count": 2
+  "diverged_commits_count": 2,
+  "task_completion_status":{
+    "count":0,
+    "completed_count":0
+  }
 }
 ```
 
@@ -1345,7 +1381,7 @@ If the rebase operation is ongoing, the response will include the following:
 
 ```json
 {
-  "rebase_in_progress": true
+  "rebase_in_progress": true,
   "merge_error": null
 }
 ```
@@ -1356,7 +1392,7 @@ the following:
 ```json
 {
   "rebase_in_progress": false,
-  "merge_error": null,
+  "merge_error": null
 }
 ```
 
@@ -1365,7 +1401,7 @@ If the rebase operation fails, the response will include the following:
 ```json
 {
   "rebase_in_progress": false,
-  "merge_error": "Rebase failed. Please rebase locally",
+  "merge_error": "Rebase failed. Please rebase locally"
 }
 ```
 
@@ -1572,7 +1608,11 @@ Example response:
     "head_sha": "2be7ddb704c7b6b83732fdd5b9f09d5a397b5f8f",
     "start_sha": "c380d3acebd181f13629a25d2e2acca46ffe1e00"
   },
-  "diverged_commits_count": 2
+  "diverged_commits_count": 2,
+  "task_completion_status":{
+    "count":0,
+    "completed_count":0
+  }
 }
 ```
 
@@ -1701,7 +1741,11 @@ Example response:
     "head_sha": "2be7ddb704c7b6b83732fdd5b9f09d5a397b5f8f",
     "start_sha": "c380d3acebd181f13629a25d2e2acca46ffe1e00"
   },
-  "diverged_commits_count": 2
+  "diverged_commits_count": 2,
+  "task_completion_status":{
+    "count":0,
+    "completed_count":0
+  }
 }
 ```