Find out data leak from the rspec example

data_leak_detector.rb

RSpec.configure do |config|
  def count_rows_from_all_tables
    Hash[
      ActiveRecord::Base.connection.tables.map do |tbl|
        [tbl, ActiveRecord::Base.connection.execute("select count(*) from #{tbl}").values.last.first.to_i]
      end
    ]
  end

  config.around :example do |example|
    old_counts = count_rows_from_all_tables

    example.run

    new_counts  = count_rows_from_all_tables
    diff_counts = Hash[new_counts.select { |tbl, new_count| new_count > old_counts[tbl] }]

    if diff_counts.present?
      FileUtils.mkdir_p('/tmp/test-results/rspec') unless File.exists?('/tmp/test-results/rspec')

      File.open('/tmp/test-results/rspec/db_changes.json', 'a') do |file|
        file << {
          desc:           example.full_description,
          location:       example.location,
          result:         {
            runtime: example.clock.now.to_f - example.execution_result.started_at.to_f
          },
          changed_tables: diff_counts
        }.to_json
        
        file << "\n"
      end
    end
  end
end