1 files changed, 198 insertions, 0 deletions
diff --git a/spec/support/shared_examples/workers/batched_background_migration_worker_shared_examples.rb b/spec/support/shared_examples/workers/batched_background_migration_worker_shared_examples.rb
new file mode 100644
index 00000000000..d202c4e00f0
--- /dev/null
+++ b/spec/support/shared_examples/workers/batched_background_migration_worker_shared_examples.rb
@@ -0,0 +1,198 @@
+# frozen_string_literal: true
+
+RSpec.shared_examples 'it runs batched background migration jobs' do |tracking_database|
+  include ExclusiveLeaseHelpers
+
+  describe 'defining the job attributes' do
+    it 'defines the data_consistency as always' do
+      expect(described_class.get_data_consistency).to eq(:always)
+    end
+
+    it 'defines the feature_category as database' do
+      expect(described_class.get_feature_category).to eq(:database)
+    end
+
+    it 'defines the idempotency as true' do
+      expect(described_class.idempotent?).to be_truthy
+    end
+  end
+
+  describe '.tracking_database' do
+    it 'does not raise an error' do
+      expect { described_class.tracking_database }.not_to raise_error
+    end
+
+    it 'overrides the method to return the tracking database' do
+      expect(described_class.tracking_database).to eq(tracking_database)
+    end
+  end
+
+  describe '.lease_key' do
+    let(:lease_key) { described_class.name.demodulize.underscore }
+
+    it 'does not raise an error' do
+      expect { described_class.lease_key }.not_to raise_error
+    end
+
+    it 'returns the lease key' do
+      expect(described_class.lease_key).to eq(lease_key)
+    end
+  end
+
+  describe '#perform' do
+    subject(:worker) { described_class.new }
+
+    context 'when the base model does not exist' do
+      before do
+        if Gitlab::Database.has_config?(tracking_database)
+          skip "because the base model for #{tracking_database} exists"
+        end
+      end
+
+      it 'does nothing' do
+        expect(worker).not_to receive(:active_migration)
+        expect(worker).not_to receive(:run_active_migration)
+
+        expect { worker.perform }.not_to raise_error
+      end
+
+      it 'logs a message indicating execution is skipped' do
+        expect(Sidekiq.logger).to receive(:info) do |payload|
+          expect(payload[:class]).to eq(described_class.name)
+          expect(payload[:database]).to eq(tracking_database)
+          expect(payload[:message]).to match(/skipping migration execution/)
+        end
+
+        expect { worker.perform }.not_to raise_error
+      end
+    end
+
+    context 'when the base model does exist' do
+      before do
+        unless Gitlab::Database.has_config?(tracking_database)
+          skip "because the base model for #{tracking_database} does not exist"
+        end
+      end
+
+      context 'when the feature flag is disabled' do
+        before do
+          stub_feature_flags(execute_batched_migrations_on_schedule: false)
+        end
+
+        it 'does nothing' do
+          expect(worker).not_to receive(:active_migration)
+          expect(worker).not_to receive(:run_active_migration)
+
+          worker.perform
+        end
+      end
+
+      context 'when the feature flag is enabled' do
+        before do
+          stub_feature_flags(execute_batched_migrations_on_schedule: true)
+
+          allow(Gitlab::Database::BackgroundMigration::BatchedMigration).to receive(:active_migration).and_return(nil)
+        end
+
+        context 'when no active migrations exist' do
+          it 'does nothing' do
+            expect(worker).not_to receive(:run_active_migration)
+
+            worker.perform
+          end
+        end
+
+        context 'when active migrations exist' do
+          let(:job_interval) { 5.minutes }
+          let(:lease_timeout) { 15.minutes }
+          let(:lease_key) { described_class.name.demodulize.underscore }
+          let(:migration) { build(:batched_background_migration, :active, interval: job_interval) }
+          let(:interval_variance) { described_class::INTERVAL_VARIANCE }
+
+          before do
+            allow(Gitlab::Database::BackgroundMigration::BatchedMigration).to receive(:active_migration)
+              .and_return(migration)
+
+            allow(migration).to receive(:interval_elapsed?).with(variance: interval_variance).and_return(true)
+            allow(migration).to receive(:reload)
+          end
+
+          context 'when the reloaded migration is no longer active' do
+            it 'does not run the migration' do
+              expect_to_obtain_exclusive_lease(lease_key, timeout: lease_timeout)
+
+              expect(migration).to receive(:reload)
+              expect(migration).to receive(:active?).and_return(false)
+
+              expect(worker).not_to receive(:run_active_migration)
+
+              worker.perform
+            end
+          end
+
+          context 'when the interval has not elapsed' do
+            it 'does not run the migration' do
+              expect_to_obtain_exclusive_lease(lease_key, timeout: lease_timeout)
+
+              expect(migration).to receive(:interval_elapsed?).with(variance: interval_variance).and_return(false)
+
+              expect(worker).not_to receive(:run_active_migration)
+
+              worker.perform
+            end
+          end
+
+          context 'when the reloaded migration is still active and the interval has elapsed' do
+            it 'runs the migration' do
+              expect_to_obtain_exclusive_lease(lease_key, timeout: lease_timeout)
+
+              expect_next_instance_of(Gitlab::Database::BackgroundMigration::BatchedMigrationRunner) do |instance|
+                expect(instance).to receive(:run_migration_job).with(migration)
+              end
+
+              expect(worker).to receive(:run_active_migration).and_call_original
+
+              worker.perform
+            end
+          end
+
+          context 'when the calculated timeout is less than the minimum allowed' do
+            let(:minimum_timeout) { described_class::MINIMUM_LEASE_TIMEOUT }
+            let(:job_interval) { 2.minutes }
+
+            it 'sets the lease timeout to the minimum value' do
+              expect_to_obtain_exclusive_lease(lease_key, timeout: minimum_timeout)
+
+              expect_next_instance_of(Gitlab::Database::BackgroundMigration::BatchedMigrationRunner) do |instance|
+                expect(instance).to receive(:run_migration_job).with(migration)
+              end
+
+              expect(worker).to receive(:run_active_migration).and_call_original
+
+              worker.perform
+            end
+          end
+
+          it 'always cleans up the exclusive lease' do
+            lease = stub_exclusive_lease_taken(lease_key, timeout: lease_timeout)
+
+            expect(lease).to receive(:try_obtain).and_return(true)
+
+            expect(worker).to receive(:run_active_migration).and_raise(RuntimeError, 'I broke')
+            expect(lease).to receive(:cancel)
+
+            expect { worker.perform }.to raise_error(RuntimeError, 'I broke')
+          end
+
+          it 'receives the correct connection' do
+            base_model = Gitlab::Database.database_base_models[tracking_database]
+
+            expect(Gitlab::Database::SharedModel).to receive(:using_connection).with(base_model.connection).and_yield
+
+            worker.perform
+          end
+        end
+      end
+    end
+  end
+end