1 files changed, 176 insertions, 0 deletions
diff --git a/spec/lib/gitlab/database/async_indexes/migration_helpers_spec.rb b/spec/lib/gitlab/database/async_indexes/migration_helpers_spec.rb
new file mode 100644
index 00000000000..ed15951dfb0
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+++ b/spec/lib/gitlab/database/async_indexes/migration_helpers_spec.rb
@@ -0,0 +1,176 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Database::AsyncIndexes::MigrationHelpers do
+  let(:migration) { ActiveRecord::Migration.new.extend(described_class) }
+  let(:index_model) { Gitlab::Database::AsyncIndexes::PostgresAsyncIndex }
+  let(:connection) { ApplicationRecord.connection }
+  let(:table_name) { '_test_async_indexes' }
+  let(:index_name) { "index_#{table_name}_on_id" }
+
+  before do
+    allow(migration).to receive(:puts)
+  end
+
+  describe '#unprepare_async_index' do
+    let!(:async_index) { create(:postgres_async_index, name: index_name) }
+
+    context 'when the flag is enabled' do
+      before do
+        stub_feature_flags(database_async_index_creation: true)
+      end
+
+      it 'destroys the record' do
+        expect do
+          migration.unprepare_async_index(table_name, 'id')
+        end.to change { index_model.where(name: index_name).count }.by(-1)
+      end
+
+      context 'when an explicit name is given' do
+        let(:index_name) { 'my_test_async_index' }
+
+        it 'destroys the record' do
+          expect do
+            migration.unprepare_async_index(table_name, 'id', name: index_name)
+          end.to change { index_model.where(name: index_name).count }.by(-1)
+        end
+      end
+
+      context 'when the async index table does not exist' do
+        it 'does not raise an error' do
+          connection.drop_table(:postgres_async_indexes)
+
+          expect(index_model).not_to receive(:find_by)
+
+          expect { migration.unprepare_async_index(table_name, 'id') }.not_to raise_error
+        end
+      end
+    end
+
+    context 'when the feature flag is disabled' do
+      it 'does not destroy the record' do
+        stub_feature_flags(database_async_index_creation: false)
+
+        expect do
+          migration.unprepare_async_index(table_name, 'id')
+        end.not_to change { index_model.where(name: index_name).count }
+      end
+    end
+  end
+
+  describe '#unprepare_async_index_by_name' do
+    let(:index_name) { "index_#{table_name}_on_id" }
+    let!(:async_index) { create(:postgres_async_index, name: index_name) }
+
+    context 'when the flag is enabled' do
+      before do
+        stub_feature_flags(database_async_index_creation: true)
+      end
+
+      it 'destroys the record' do
+        expect do
+          migration.unprepare_async_index_by_name(table_name, index_name)
+        end.to change { index_model.where(name: index_name).count }.by(-1)
+      end
+
+      context 'when the async index table does not exist' do
+        it 'does not raise an error' do
+          connection.drop_table(:postgres_async_indexes)
+
+          expect(index_model).not_to receive(:find_by)
+
+          expect { migration.unprepare_async_index_by_name(table_name, index_name) }.not_to raise_error
+        end
+      end
+    end
+
+    context 'when the feature flag is disabled' do
+      it 'does not destroy the record' do
+        stub_feature_flags(database_async_index_creation: false)
+
+        expect do
+          migration.unprepare_async_index_by_name(table_name, index_name)
+        end.not_to change { index_model.where(name: index_name).count }
+      end
+    end
+  end
+
+  describe '#prepare_async_index' do
+    before do
+      connection.create_table(table_name)
+    end
+
+    context 'when the feature flag is enabled' do
+      before do
+        stub_feature_flags(database_async_index_creation: true)
+      end
+
+      it 'creates the record for the async index' do
+        expect do
+          migration.prepare_async_index(table_name, 'id')
+        end.to change { index_model.where(name: index_name).count }.by(1)
+
+        record = index_model.find_by(name: index_name)
+
+        expect(record.table_name).to eq(table_name)
+        expect(record.definition).to match(/CREATE INDEX CONCURRENTLY "#{index_name}"/)
+      end
+
+      context 'when an explicit name is given' do
+        let(:index_name) { 'my_async_index_name' }
+
+        it 'creates the record with the given name' do
+          expect do
+            migration.prepare_async_index(table_name, 'id', name: index_name)
+          end.to change { index_model.where(name: index_name).count }.by(1)
+
+          record = index_model.find_by(name: index_name)
+
+          expect(record.table_name).to eq(table_name)
+          expect(record.definition).to match(/CREATE INDEX CONCURRENTLY "#{index_name}"/)
+        end
+      end
+
+      context 'when the index already exists' do
+        it 'does not create the record' do
+          connection.add_index(table_name, 'id', name: index_name)
+
+          expect do
+            migration.prepare_async_index(table_name, 'id')
+          end.not_to change { index_model.where(name: index_name).count }
+        end
+      end
+
+      context 'when the record already exists' do
+        it 'does attempt to create the record' do
+          create(:postgres_async_index, table_name: table_name, name: index_name)
+
+          expect do
+            migration.prepare_async_index(table_name, 'id')
+          end.not_to change { index_model.where(name: index_name).count }
+        end
+      end
+
+      context 'when the async index table does not exist' do
+        it 'does not raise an error' do
+          connection.drop_table(:postgres_async_indexes)
+
+          expect(index_model).not_to receive(:safe_find_or_create_by!)
+
+          expect { migration.prepare_async_index(table_name, 'id') }.not_to raise_error
+        end
+      end
+    end
+
+    context 'when the feature flag is disabled' do
+      it 'does not create the record' do
+        stub_feature_flags(database_async_index_creation: false)
+
+        expect do
+          migration.prepare_async_index(table_name, 'id')
+        end.not_to change { index_model.where(name: index_name).count }
+      end
+    end
+  end
+end