在Pundit策略上运行Rspec测试，不会在每次测试后清理数据

Question

Rails 5.2 Rspec 3.7 Pundit 1.10

以下针对我的政策的Rspec测试失败并显示错误：

spec / policies / proofreader / dashboard

describe Proofreader::DashboardPolicy do
  subject { described_class }

  context 'accessing the proofreader dashboard' do

    permissions :index? do

      it "denies access to admins" do
        expect(subject).not_to permit(FactoryBot.create(:admin))
      end

    end
  end
end




Error:      ActiveRecord::RecordInvalid:
       Validation failed: Email has already been taken

此测试在数据库清理时第一次通过，但随后失败。

我的用户工厂使用序列，因此电子邮件不同：

FactoryBot.define do
  factory :user, aliases: [:client] do
    sequence(:email) { |n| "tester#{n}@example.com" }
    password 123456
    password_confirmation 123456

    factory :admin do
      after(:build) {|user| user.admin = true }
    end

    factory :proofreader do
      after(:build) {|user| user.proofreader = true }
    end

    factory :admin_proofreader do
      after(:build) {|user| user.admin = true && user.proofreader = true}
    end

  end
end

为什么我会收到此错误以及如何解决？