1 files changed, 62 insertions, 0 deletions
diff --git a/spec/workers/merge_requests/handle_assignees_change_worker_spec.rb b/spec/workers/merge_requests/handle_assignees_change_worker_spec.rb
new file mode 100644
index 00000000000..4b45f3562d6
--- /dev/null
+++ b/spec/workers/merge_requests/handle_assignees_change_worker_spec.rb
@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe MergeRequests::HandleAssigneesChangeWorker do
+  include AfterNextHelpers
+
+  let_it_be(:merge_request) { create(:merge_request) }
+  let_it_be(:user) { create(:user) }
+  let_it_be(:old_assignees) { create_list(:user, 3) }
+
+  let(:user_ids) { old_assignees.map(&:id).to_a }
+  let(:options) { {} }
+  let(:worker) { described_class.new }
+
+  it_behaves_like 'an idempotent worker' do
+    let(:job_args) { [merge_request.id, user.id, user_ids, options] }
+  end
+
+  describe '#perform' do
+    it 'calls MergeRequests::HandleAssigneesChangeService#execute to handle the changes' do
+      expect_next(::MergeRequests::HandleAssigneesChangeService)
+        .to receive(:execute).with(merge_request, match_array(old_assignees), options)
+
+      worker.perform(merge_request.id, user.id, user_ids, options)
+    end
+
+    context 'when there are no changes' do
+      it 'still calls MergeRequests::HandleAssigneesChangeService#execute' do
+        expect_next(::MergeRequests::HandleAssigneesChangeService)
+          .to receive(:execute).with(merge_request, [], options)
+
+        worker.perform(merge_request.id, user.id, merge_request.assignee_ids, options)
+      end
+    end
+
+    context 'when the old assignees cannot be found' do
+      it 'still calls MergeRequests::HandleAssigneesChangeService#execute' do
+        expect_next(::MergeRequests::HandleAssigneesChangeService)
+          .to receive(:execute).with(merge_request, [], options)
+
+        worker.perform(merge_request.id, user.id, [non_existing_record_id], options)
+      end
+    end
+
+    context 'with a non-existing merge request' do
+      it 'does nothing' do
+        expect(::MergeRequests::HandleAssigneesChangeService).not_to receive(:new)
+
+        worker.perform(non_existing_record_id, user.id, user_ids, options)
+      end
+    end
+
+    context 'with a non-existing user' do
+      it 'does nothing' do
+        expect(::MergeRequests::HandleAssigneesChangeService).not_to receive(:new)
+
+        worker.perform(merge_request.id, non_existing_record_id, user_ids, options)
+      end
+    end
+  end
+end