1 files changed, 34 insertions, 0 deletions
diff --git a/spec/features/merge_request/user_sees_mr_with_deleted_source_branch_spec.rb b/spec/features/merge_request/user_sees_mr_with_deleted_source_branch_spec.rb
new file mode 100644
index 00000000000..c1608be402a
--- /dev/null
+++ b/spec/features/merge_request/user_sees_mr_with_deleted_source_branch_spec.rb
@@ -0,0 +1,34 @@
+require 'rails_helper'
+
+# This test serves as a regression test for a bug that caused an error
+# message to be shown by JavaScript when the source branch was deleted.
+# Please do not remove ":js".
+describe 'Merge request > User sees MR with deleted source branch', :js do
+  let(:project) { create(:project, :public, :repository) }
+  let(:merge_request) { create(:merge_request, source_project: project) }
+  let(:user) { project.creator }
+
+  before do
+    merge_request.update!(source_branch: 'this-branch-does-not-exist')
+    sign_in(user)
+    visit project_merge_request_path(project, merge_request)
+  end
+
+  it 'shows a message about missing source branch' do
+    expect(page).to have_content('Source branch does not exist.')
+  end
+
+  it 'still contains Discussion, Commits and Changes tabs' do
+    within '.merge-request-details' do
+      expect(page).to have_content('Discussion')
+      expect(page).to have_content('Commits')
+      expect(page).to have_content('Changes')
+    end
+
+    click_on 'Changes'
+    wait_for_requests
+
+    expect(page).to have_selector('.diffs.tab-pane .nothing-here-block')
+    expect(page).to have_content('Source branch does not exist.')
+  end
+end