1 files changed, 32 insertions, 0 deletions
diff --git a/spec/migrations/assure_commits_count_for_merge_request_diff_spec.rb b/spec/migrations/assure_commits_count_for_merge_request_diff_spec.rb
new file mode 100644
index 00000000000..b8c3a3eda4e
--- /dev/null
+++ b/spec/migrations/assure_commits_count_for_merge_request_diff_spec.rb
@@ -0,0 +1,32 @@
+require 'spec_helper'
+require Rails.root.join('db', 'migrate', '20180425131009_assure_commits_count_for_merge_request_diff.rb')
+
+describe AssureCommitsCountForMergeRequestDiff, :migration, :sidekiq, :redis do
+  let(:migration) { spy('migration') }
+
+  before do
+    allow(Gitlab::BackgroundMigration::AddMergeRequestDiffCommitsCount)
+      .to receive(:new).and_return(migration)
+  end
+
+  context 'when there are still unmigrated commit_counts afterwards' do
+    let(:namespaces) { table('namespaces') }
+    let(:projects) { table('projects') }
+    let(:merge_requests) { table('merge_requests') }
+    let(:diffs) { table('merge_request_diffs') }
+
+    before do
+      namespace = namespaces.create(name: 'foo', path: 'foo')
+      project = projects.create!(namespace_id: namespace.id)
+      merge_request = merge_requests.create!(source_branch: 'x', target_branch: 'y', target_project_id: project.id)
+      diffs.create!(commits_count: nil, merge_request_id: merge_request.id)
+      diffs.create!(commits_count: nil, merge_request_id: merge_request.id)
+    end
+
+    it 'migrates commit_counts sequentially in batches' do
+      migrate!
+
+      expect(migration).to have_received(:perform).once
+    end
+  end
+end