find broken factory_bot factories that don't work or create excessive records

factory_bot_spec.rb

FactoryBot.factories.each do |factory|
  name = factory.names.count == 1 ? factory.names.first : fail
  klass = factory.build_class
  next unless ActiveRecord::Base.in?(klass.ancestors)

  RSpec.describe "factory :#{name}" do
    it "creates a single #{klass} and no insane number of other records" do
      record_counts = -> do
        ActiveRecord::Base.descendants.to_h { |c| [c.name.to_sym, (c.count rescue 0)] }
      end
      old_counts = record_counts.call
      expect { create(name) }.to change { klass.count }.by(1)
      new_counts = record_counts.call
      added = new_counts.values.sum(0) - old_counts.values.sum(0)
      expect(added).to be < 10,
        "expected less than 10 added records, got #{added}: "\
        "#{new_counts.to_h { |k, v| [k, v - (old_counts[k] || 0)] }.reject { |k, v| v == 0 }}"
    end
  end
end