1 files changed, 73 insertions, 0 deletions
diff --git a/spec/workers/redis_migration_worker_spec.rb b/spec/workers/redis_migration_worker_spec.rb
new file mode 100644
index 00000000000..ad0186e929d
--- /dev/null
+++ b/spec/workers/redis_migration_worker_spec.rb
@@ -0,0 +1,73 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe RedisMigrationWorker, :clean_gitlab_redis_shared_state, feature_category: :redis do
+  describe '.fetch_migrator!' do
+    it 'raise error if class does not exist' do
+      expect { described_class.fetch_migrator!('UnknownClass') }.to raise_error(NotImplementedError)
+    end
+
+    context 'when class exists' do
+      it 'returns an instance' do
+        expect(
+          described_class.fetch_migrator!('BackfillProjectPipelineStatusTtl')
+        ).to be_a Gitlab::BackgroundMigration::Redis::BackfillProjectPipelineStatusTtl
+      end
+    end
+  end
+
+  describe '#perform' do
+    let(:job_class_name) { 'SampleJob' }
+    let(:migrator_class) do
+      Class.new do
+        def perform(keys)
+          keys.each { |key| redis.set(key, "adjusted", ex: 10) }
+        end
+
+        def scan_match_pattern
+          'sample:*:pattern'
+        end
+
+        def redis
+          ::Redis.new(::Gitlab::Redis::Cache.params)
+        end
+      end
+    end
+
+    let(:migrator) { migrator_class.new }
+
+    before do
+      allow(described_class).to receive(:fetch_migrator!).with(job_class_name).and_return(migrator)
+
+      100.times do |i|
+        migrator.redis.set("sample:#{i}:pattern", i)
+      end
+    end
+
+    it 'runs migration logic on scanned keys' do
+      expect(migrator).to receive(:perform)
+
+      subject.perform(job_class_name, '0')
+    end
+
+    context 'when job exceeds deadline' do
+      before do
+        # stub Time.now to force the 3rd invocation to timeout
+        now = Time.now # rubocop:disable Rails/TimeZone
+        allow(Time).to receive(:now).and_return(now, now, now + 5.minutes)
+      end
+
+      it 'enqueues another job and returns' do
+        expect(described_class).to receive(:perform_async)
+
+        # use smaller scan_size to ensure multiple scans are required
+        subject.perform(job_class_name, '0', { scan_size: 10 })
+      end
+    end
+
+    it_behaves_like 'an idempotent worker' do
+      let(:job_args) { [job_class_name, '0'] }
+    end
+  end
+end