Update tests to reflect sub-batched query

lib/gitlab/background_migration/backfill_user_namespace.rb

@@ -7,23 +7,15 @@ module Gitlab
     class BackfillUserNamespace
       include Gitlab::Database::DynamicModelHelpers
 
-      def perform(start_id, end_id, batch_table, batch_column, sub_batch_size)
+      def perform(start_id, end_id, batch_table, batch_column, sub_batch_size, pause_ms)
         parent_batch_relation = relation_scoped_to_range(batch_table, batch_column, start_id, end_id)
-
-        parent_batch_relation.each_batch(column: batch_column, of: sub_batch_size) do |sub_batch|
+        parent_batch_relation.each_batch(column: batch_column, of: sub_batch_size, order_hint: :type) do |sub_batch|
           batch_metrics.time_operation(:update_all) do
             sub_batch.update_all(type: 'User')
           end
-
           pause_ms = 0 if pause_ms < 0
           sleep(pause_ms * 0.001)
         end
-
-        # ActiveRecord::Base.connection.execute(<<~SQL)
-        #   UPDATE namespaces SET type = 'User'
-        #   WHERE id BETWEEN #{start_id} AND #{end_id}
-        #     AND type IS NULL
-        # SQL
       end
 
       def batch_metrics

spec/lib/gitlab/background_migration/backfill_user_namespace_spec.rb

@@ -2,24 +2,38 @@
 
 require 'spec_helper'
 
-RSpec.describe Gitlab::BackgroundMigration::BackfillUserNamespace do
+RSpec.describe Gitlab::BackgroundMigration::BackfillUserNamespace, :migration, schema: 20210930211936 do
   let(:migration) { described_class.new }
-  let(:namespaces) { table(:namespaces) }
+  let(:namespaces_table) { table(:namespaces) }
+
+  let(:table_name) { 'namespaces' }
+  let(:batch_column) { :id }
+  let(:sub_batch_size) { 100 }
+  let(:pause_ms) { 0 }
+
+  subject(:perform_migration) { migration.perform(1, 10, table_name, batch_column, sub_batch_size, pause_ms) }
 
   before do
-    namespaces.create!(id: 1, name: 'test1', path: 'test1', type: nil)
-    namespaces.create!(id: 2, name: 'test2', path: 'test2', type: 'User')
-    namespaces.create!(id: 3, name: 'test3', path: 'test3', type: 'Group')
-    namespaces.create!(id: 4, name: 'test4', path: 'test4', type: nil)
-    namespaces.create!(id: 11, name: 'test11', path: 'test11', type: nil)
+    namespaces_table.create!(id: 1, name: 'test1', path: 'test1', type: nil)
+    namespaces_table.create!(id: 2, name: 'test2', path: 'test2', type: 'User')
+    namespaces_table.create!(id: 3, name: 'test3', path: 'test3', type: 'Group')
+    namespaces_table.create!(id: 4, name: 'test4', path: 'test4', type: nil)
+    namespaces_table.create!(id: 11, name: 'test11', path: 'test11', type: nil)
   end
 
-  it 'backfills `type` for the selected records' do
+  it 'backfills `type` for the selected records', :aggregate_failures do
     queries = ActiveRecord::QueryRecorder.new do
-      migration.perform(1, 10)
+      perform_migration
     end
 
-    expect(queries.count).to be(1)
-    expect(Namespace.where(type: 'User').count).to eq 3
+    expect(queries.count).to eq(3)
+    expect(namespaces_table.where(type: 'User').count).to eq 3
+    expect(namespaces_table.where(type: 'User').pluck(:id)).to match_array([1, 2, 4])
+  end
+
+  it 'tracks timings of queries' do
+    expect(migration.batch_metrics.timings).to be_empty
+
+    expect { perform_migration }.to change { migration.batch_metrics.timings }
   end
 end