Fix bug on MR title ending with `wip`/`draft`

MR title ending with `wip` or `draft` should not
be marked as draft MR.

Similarly, these MR titles should not have
`wip`/`draft` words removed.

lib/gitlab/regex.rb

@@ -385,11 +385,11 @@ module Gitlab
     end
 
     def merge_request_wip
-      /(?i)(\[WIP\]\s*|WIP:\s*|WIP$)/
+      /(?i)(\[WIP\]\s*|WIP:\s*|\AWIP\z)/
     end
 
     def merge_request_draft
-      /(?i)(\[draft\]|\(draft\)|draft:|draft\s\-\s|draft$)/
+      /\A(?i)(\[draft\]|\(draft\)|draft:|draft\s\-\s|draft\z)/
     end
 
     def issue

spec/models/merge_request_spec.rb

@@ -1353,6 +1353,24 @@ RSpec.describe MergeRequest, factory_default: :keep do
       expect(subject.work_in_progress?).to eq false
     end
 
+    it 'does not detect Draft: in the middle of the title' do
+      subject.title = 'Something with Draft: in the middle'
+
+      expect(subject.work_in_progress?).to eq false
+    end
+
+    it 'does not detect WIP at the end of the title' do
+      subject.title = 'Something ends with WIP'
+
+      expect(subject.work_in_progress?).to eq false
+    end
+
+    it 'does not detect Draft at the end of the title' do
+      subject.title = 'Something ends with Draft'
+
+      expect(subject.work_in_progress?).to eq false
+    end
+
     it "doesn't detect WIP for words starting with WIP" do
       subject.title = "Wipwap #{subject.title}"
       expect(subject.work_in_progress?).to eq false
@@ -1363,6 +1381,11 @@ RSpec.describe MergeRequest, factory_default: :keep do
       expect(subject.work_in_progress?).to eq false
     end
 
+    it "doesn't detect draft for words containing with draft" do
+      subject.title = "Drafting #{subject.title}"
+      expect(subject.work_in_progress?).to eq false
+    end
+
     it "doesn't detect WIP by default" do
       expect(subject.work_in_progress?).to eq false
     end
@@ -1393,6 +1416,42 @@ RSpec.describe MergeRequest, factory_default: :keep do
         expect(subject.work_in_progress?).to eq false
       end
     end
+
+    it 'removes only WIP prefix from the MR title' do
+      subject.title = 'WIP: Implement feature called WIP'
+
+      expect(subject.wipless_title).to eq 'Implement feature called WIP'
+    end
+
+    it 'removes only draft prefix from the MR title' do
+      subject.title = 'Draft: Implement feature called draft'
+
+      expect(subject.wipless_title).to eq 'Implement feature called draft'
+    end
+
+    it 'does not remove WIP in the middle of the title' do
+      subject.title = 'Something with WIP in the middle'
+
+      expect(subject.wipless_title).to eq subject.title
+    end
+
+    it 'does not remove Draft in the middle of the title' do
+      subject.title = 'Something with Draft in the middle'
+
+      expect(subject.wipless_title).to eq subject.title
+    end
+
+    it 'does not remove WIP at the end of the title' do
+      subject.title = 'Something ends with WIP'
+
+      expect(subject.wipless_title).to eq subject.title
+    end
+
+    it 'does not remove Draft at the end of the title' do
+      subject.title = 'Something ends with Draft'
+
+      expect(subject.wipless_title).to eq subject.title
+    end
   end
 
   describe "#wip_title" do