1 files changed, 35 insertions, 2 deletions
diff --git a/spec/lib/gitlab/email/service_desk/custom_email_spec.rb b/spec/lib/gitlab/email/service_desk/custom_email_spec.rb
index bba1ca1c8be..bdf31567251 100644
--- a/spec/lib/gitlab/email/service_desk/custom_email_spec.rb
+++ b/spec/lib/gitlab/email/service_desk/custom_email_spec.rb
@@ -6,10 +6,9 @@ RSpec.describe Gitlab::Email::ServiceDesk::CustomEmail, feature_category: :servi
   let(:reply_key) { 'b7721fc7e8419911a8bea145236a0519' }
   let(:custom_email) { 'support@example.com' }
   let(:email_with_reply_key) { 'support+b7721fc7e8419911a8bea145236a0519@example.com' }
+  let_it_be(:project) { create(:project) }
 
   describe '.reply_address' do
-    let_it_be(:project) { create(:project) }
-
     subject(:reply_address) { described_class.reply_address(nil, nil) }
 
     it { is_expected.to be nil }
@@ -34,4 +33,38 @@ RSpec.describe Gitlab::Email::ServiceDesk::CustomEmail, feature_category: :servi
       end
     end
   end
+
+  describe '.key_from_reply_address' do
+    let(:email) { email_with_reply_key }
+
+    subject(:reply_address) { described_class.key_from_reply_address(email) }
+
+    it { is_expected.to be nil }
+
+    context 'with service_desk_setting' do
+      let_it_be_with_refind(:setting) do
+        create(:service_desk_setting, project: project, add_external_participants_from_cc: true)
+      end
+
+      it { is_expected.to be nil }
+
+      context 'with custom email' do
+        let!(:credential) { create(:service_desk_custom_email_credential, project: project) }
+        let!(:verification) { create(:service_desk_custom_email_verification, :finished, project: project) }
+
+        before do
+          project.reset
+          setting.update!(custom_email: 'support@example.com', custom_email_enabled: true)
+        end
+
+        it { is_expected.to eq reply_key }
+      end
+    end
+
+    context 'without reply key' do
+      let(:email) { custom_email }
+
+      it { is_expected.to be nil }
+    end
+  end
 end