Merge branch 'feature/group-level-labels' into 'master'

Add group level labels

## What does this MR do?

Add group level labels.

## Are there points in the code the reviewer needs to double check?

* `LabelsFinder`
* `Gitlab::Gfm::ReferenceRewriter`
* `Banzai::Filter::LabelReferenceFilter`

## Why was this MR needed?

We'll be adding more feature that allow you to do cross-project management of issues.

## Screenshots (if relevant)

* Group Labels
    ![Group Labels](/uploads/2244c06ad68eae4fb246fb4c81bf8060/2.png)

* Project Labels
    ![Project Labels](/uploads/c5839516d2282b51f7418d9dadbeceb4/1.png)

* Expanded references for group labels when moving issue to another project
    ![Expanded references for group labels when moving issue to another project](/uploads/0c9ab248a8420d4978d59349ae3d42e5/3.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

#19997

See merge request !6425

3 files changed, 34 insertions, 1 deletions

diff --git a/spec/factories/label_priorities.rb b/spec/factories/label_priorities.rb
new file mode 100644
index 00000000000..f25939d2d3e
--- /dev/null
+++ b/spec/factories/label_priorities.rb
@@ -0,0 +1,7 @@
+FactoryGirl.define do
+  factory :label_priority do
+    project factory: :empty_project
+    label
+    sequence(:priority)
+  end
+end
diff --git a/spec/factories/labels.rb b/spec/factories/labels.rb
index eb489099854..3e8822faf97 100644
--- a/spec/factories/labels.rb
+++ b/spec/factories/labels.rb
@@ -1,7 +1,23 @@
 FactoryGirl.define do
-  factory :label do
+  factory :label, class: ProjectLabel do
     sequence(:title) { |n| "label#{n}" }
     color "#990000"
     project
+
+    transient do
+      priority nil
+    end
+
+    after(:create) do |label, evaluator|
+      if evaluator.priority
+        label.priorities.create(project: label.project, priority: evaluator.priority)
+      end
+    end
+  end
+
+  factory :group_label, class: GroupLabel do
+    sequence(:title) { |n| "label#{n}" }
+    color "#990000"
+    group
   end
 end
diff --git a/spec/factories/merge_requests.rb b/spec/factories/merge_requests.rb
index c6a08d78b78..f780e01253c 100644
--- a/spec/factories/merge_requests.rb
+++ b/spec/factories/merge_requests.rb
@@ -68,5 +68,15 @@ FactoryGirl.define do
     factory :closed_merge_request, traits: [:closed]
     factory :reopened_merge_request, traits: [:reopened]
     factory :merge_request_with_diffs, traits: [:with_diffs]
+
+    factory :labeled_merge_request do
+      transient do
+        labels []
+      end
+
+      after(:create) do |merge_request, evaluator|
+        merge_request.update_attributes(labels: evaluator.labels)
+      end
+    end
   end
 end