Ruby on rails Rails密码验证在编写无关测试时错误地失败

我正在做MichaelHartl的Rails教程，我在

基本上，我正在构建一个Twitter克隆，以学习Rails。 在本章中，用户可以相互跟踪

编写第一个测试以检查这些关系后：

用户测试.rb 出现以下错误：

错误 触发错误的model/user.rb中的方法 其他文件

---

可以找到所有其他文件

我完成了相同的教程，并在我的用户模型中验证了密码，如下所示：

  validates :password, presence: true, length: { minimum: 6 }, allow_nil: true

也许加上allow_nil：对

ERROR["test_should_follow_and_unfollow_a_user", UserTest, .192215816000044]
test_should_follow_and_unfollow_a_user#UserTest (6.19s)
ActiveRecord::RecordInvalid:         
ActiveRecord::RecordInvalid: Validation failed: 
  Password can't be blank,        
  Password is too short (minimum is 6 characters)
        app/models/user.rb:102:in `follow'
        test/models/user_test.rb:100:in `block in <class:UserTest>'

class User < ApplicationRecord
has_many :microposts, dependent: :destroy
has_many :active_relationships,  class_name:    "Relationship",
                                 foreign_key:   "follower_id",
                                 dependent:     :destroy
has_many :following,  through:   :active_relationships,
                      source:    :followed

attr_accessor :remember_token, :activation_token, :reset_token
before_save     :downcase_email
before_create :create_activation_digest

VALID_EMAIL_REGEX = /\A[\d\+\.a-z_-]+@[a-z]+\.[a-z.]+\z/i
validates(:name,     presence: true, length: { maximum: 50 } )
validates :email,    presence: true, length: { maximum: 255 }, 
                     format: { with: VALID_EMAIL_REGEX },                
                     uniqueness: { case_sensitive: false }
validates :password, presence: true, length: { minimum: 6 }
has_secure_password

# follows a user
def follow(other_user)
    following << other_user    # LINE OF THE ERROR (rb:102)
end

michael:
  name:             Michael Example
  email:            michael@example.com
  password_digest:  <%= User.digest('password') %>
  admin:            true
  activated:        true
  activated_at:     <%= Time.zone.now %>

archer:
  name:             Sterling Archer
  email:            duchess@example.gov
  password_digest:  <%= User.digest('password') %>
  activated:        true
  activated_at:     <%= Time.zone.now %>

  validates :password, presence: true, length: { minimum: 6 }, allow_nil: true