1 files changed, 113 insertions, 0 deletions
diff --git a/spec/services/protected_branches/cache_service_spec.rb b/spec/services/protected_branches/cache_service_spec.rb
new file mode 100644
index 00000000000..4fa7553c23d
--- /dev/null
+++ b/spec/services/protected_branches/cache_service_spec.rb
@@ -0,0 +1,113 @@
+# frozen_string_literal: true
+# rubocop:disable Style/RedundantFetchBlock
+#
+require 'spec_helper'
+
+RSpec.describe ProtectedBranches::CacheService, :clean_gitlab_redis_cache do
+  subject(:service) { described_class.new(project, user) }
+
+  let_it_be(:project) { create(:project) }
+  let_it_be(:user) { project.first_owner }
+
+  let(:immediate_expiration) { 0 }
+
+  describe '#fetch' do
+    it 'caches the value' do
+      expect(service.fetch('main') { true }).to eq(true)
+      expect(service.fetch('not-found') { false }).to eq(false)
+
+      # Uses cached values
+      expect(service.fetch('main') { false }).to eq(true)
+      expect(service.fetch('not-found') { true }).to eq(false)
+    end
+
+    it 'sets expiry on the key' do
+      stub_const("#{described_class.name}::CACHE_EXPIRE_IN", immediate_expiration)
+
+      expect(service.fetch('main') { true }).to eq(true)
+      expect(service.fetch('not-found') { false }).to eq(false)
+
+      expect(service.fetch('main') { false }).to eq(false)
+      expect(service.fetch('not-found') { true }).to eq(true)
+    end
+
+    it 'does not set an expiry on the key after the hash is already created' do
+      expect(service.fetch('main') { true }).to eq(true)
+
+      stub_const("#{described_class.name}::CACHE_EXPIRE_IN", immediate_expiration)
+
+      expect(service.fetch('not-found') { false }).to eq(false)
+
+      expect(service.fetch('main') { false }).to eq(true)
+      expect(service.fetch('not-found') { true }).to eq(false)
+    end
+
+    context 'when CACHE_LIMIT is exceeded' do
+      before do
+        stub_const("#{described_class.name}::CACHE_LIMIT", 2)
+      end
+
+      it 'recreates cache' do
+        expect(service.fetch('main') { true }).to eq(true)
+        expect(service.fetch('not-found') { false }).to eq(false)
+
+        # Uses cached values
+        expect(service.fetch('main') { false }).to eq(true)
+        expect(service.fetch('not-found') { true }).to eq(false)
+
+        # Overflow
+        expect(service.fetch('new-branch') { true }).to eq(true)
+
+        # Refreshes values
+        expect(service.fetch('main') { false }).to eq(false)
+        expect(service.fetch('not-found') { true }).to eq(true)
+      end
+    end
+
+    context 'when dry_run is on' do
+      it 'does not use cached value' do
+        expect(service.fetch('main', dry_run: true) { true }).to eq(true)
+        expect(service.fetch('main', dry_run: true) { false }).to eq(false)
+      end
+
+      context 'when cache mismatch' do
+        it 'logs an error' do
+          expect(service.fetch('main', dry_run: true) { true }).to eq(true)
+
+          expect(Gitlab::AppLogger).to receive(:error).with(
+            'class' => described_class.name,
+            'message' => /Cache mismatch/,
+            'project_id' => project.id,
+            'project_path' => project.full_path
+          )
+
+          expect(service.fetch('main', dry_run: true) { false }).to eq(false)
+        end
+      end
+
+      context 'when cache matches' do
+        it 'does not log an error' do
+          expect(service.fetch('main', dry_run: true) { true }).to eq(true)
+
+          expect(Gitlab::AppLogger).not_to receive(:error)
+
+          expect(service.fetch('main', dry_run: true) { true }).to eq(true)
+        end
+      end
+    end
+  end
+
+  describe '#refresh' do
+    it 'clears cached values' do
+      expect(service.fetch('main') { true }).to eq(true)
+      expect(service.fetch('not-found') { false }).to eq(false)
+
+      service.refresh
+
+      # Recreates cache
+      expect(service.fetch('main') { false }).to eq(false)
+      expect(service.fetch('not-found') { true }).to eq(true)
+    end
+  end
+end
+# rubocop:enable Style/RedundantFetchBlock