1 files changed, 31 insertions, 0 deletions
diff --git a/spec/lib/gitlab/background_migration/rebuild_trigram_index_spec.rb b/spec/lib/gitlab/background_migration/rebuild_trigram_index_spec.rb
new file mode 100644
index 00000000000..575b4db6e3a
--- /dev/null
+++ b/spec/lib/gitlab/background_migration/rebuild_trigram_index_spec.rb
@@ -0,0 +1,31 @@
+require 'spec_helper'
+
+describe Gitlab::BackgroundMigration::RebuildTrigramIndex, :migration, schema: 20180608201435, if: Gitlab::Database.postgresql? do
+  subject { migration.perform(table, column) }
+  let(:table) { "issues" }
+  let(:column) { "description" }
+  let(:migration) { described_class.new }
+
+  let(:index_name) { "index_#{table}_on_#{column}_trigram" }
+  let(:index_name_old) { "#{index_name}_old" }
+
+  it 'renames the existing index' do
+    expect(migration).to receive(:rename_index).with(table, index_name, index_name_old).and_call_original
+
+    subject
+  end
+
+  it 'creates a new index' do
+    allow(migration).to receive(:execute)
+
+    expect(migration).to receive(:execute).with("CREATE INDEX CONCURRENTLY #{index_name} ON #{table} USING gin(#{column} gin_trgm_ops);").and_call_original
+
+    subject
+  end
+
+  it 'drops the renamed index' do
+    expect(migration).to receive(:remove_concurrent_index_by_name).with(table, index_name_old).and_call_original
+
+    subject
+  end
+end