Merge branch 'support-edit-target-branch-in-mr' into 'master'

Support editing target branch of merge request

### What does this MR do?

This MR makes it possible to edit the target branch of a merge request and adds a system note when this happens.

### Why was this MR needed?

Because lots of people requested this feature. :)

### Screenshots

**Edit MR page**

![image](https://gitlab.com/gitlab-org/gitlab-ce/uploads/9b3d405bf7b5f945e35bae3534c2b67b/image.png)

**New MR page**

![image](https://gitlab.com/gitlab-org/gitlab-ce/uploads/3657a2a9efad6d10e8470637d1166bdb/image.png)

**System note**

![image](https://gitlab.com/gitlab-org/gitlab-ce/uploads/cc8066f3d3bdf09c0cce27193210567d/image.png)

### What are the relevant issue numbers?

* Closes https://github.com/gitlabhq/gitlabhq/issues/7105
* See: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/130!

See merge request !738

2 files changed, 24 insertions, 1 deletions

diff --git a/spec/services/merge_requests/update_service_spec.rb b/spec/services/merge_requests/update_service_spec.rb
index 0a0760056cf..c75173c1452 100644
--- a/spec/services/merge_requests/update_service_spec.rb
+++ b/spec/services/merge_requests/update_service_spec.rb
@@ -20,7 +20,8 @@ describe MergeRequests::UpdateService do
           description: 'Also please fix',
           assignee_id: user2.id,
           state_event: 'close',
-          label_ids: [label.id]
+          label_ids: [label.id],
+          target_branch: 'target'
         }
       end
 
@@ -39,6 +40,7 @@ describe MergeRequests::UpdateService do
       it { expect(@merge_request).to be_closed }
       it { expect(@merge_request.labels.count).to eq(1) }
       it { expect(@merge_request.labels.first.title).to eq('Bug') }
+      it { expect(@merge_request.target_branch).to eq('target') }
 
       it 'should execute hooks with update action' do
         expect(service).to have_received(:execute_hooks).
@@ -77,6 +79,13 @@ describe MergeRequests::UpdateService do
         expect(note).not_to be_nil
         expect(note.note).to eq 'Title changed from **Old title** to **New title**'
       end
+
+      it 'creates system note about branch change' do
+        note = find_note('Target')
+
+        expect(note).not_to be_nil
+        expect(note.note).to eq 'Target branch changed from `master` to `target`'
+      end
     end
   end
 end
diff --git a/spec/services/system_note_service_spec.rb b/spec/services/system_note_service_spec.rb
index 0dcc94e8bd4..700286b585a 100644
--- a/spec/services/system_note_service_spec.rb
+++ b/spec/services/system_note_service_spec.rb
@@ -228,6 +228,20 @@ describe SystemNoteService do
     end
   end
 
+  describe '.change_branch' do
+    subject { described_class.change_branch(noteable, project, author, 'target', old_branch, new_branch) }
+    let(:old_branch) { 'old_branch'}
+    let(:new_branch) { 'new_branch'}
+
+    it_behaves_like 'a system note'
+
+    context 'when target branch name changed' do
+      it 'sets the note text' do
+        expect(subject.note).to eq "Target branch changed from `#{old_branch}` to `#{new_branch}`"
+      end
+    end
+  end
+
   describe '.cross_reference' do
     subject { described_class.cross_reference(noteable, mentioner, author) }