Add the ability to perform background migrations

Background migrations can be used to perform long running data
migrations without these blocking a deployment procedure.

See MR https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/11854 for
more information.

1 files changed, 13 insertions, 0 deletions

diff --git a/spec/workers/background_migration_worker_spec.rb b/spec/workers/background_migration_worker_spec.rb
new file mode 100644
index 00000000000..0d742ae9dc7
--- /dev/null
+++ b/spec/workers/background_migration_worker_spec.rb
@@ -0,0 +1,13 @@
+require 'spec_helper'
+
+describe BackgroundMigrationWorker do
+  describe '.perform' do
+    it 'performs a background migration' do
+      expect(Gitlab::BackgroundMigration).
+        to receive(:perform).
+        with('Foo', [10, 20])
+
+      described_class.new.perform('Foo', [10, 20])
+    end
+  end
+end