undefined method `validate_presence_of'
https://github.com/thoughtbot/shoulda-matchers
加了gem 'shoulda-matchers', '~> 3.0',
报错是因为没有配置spec/rails_helper.rb,详细内容在上面连接里的configuration里
Shoulda::Matchers.configure do |config| config.integrate do |with| # Choose a test framework: with.test_framework :rspec with.library :rails end end