测试时按特定顺序加载Rails夹具 [英] Loading Rails Fixtures in a Specific Order when Testing

问题描述

在运行测试时，是否可以按特定顺序加载Rails灯具?例如，参加以下课程...

Is there a way to load Rails fixtures in a specific order while running tests? For example, take the following classes...

class User < ActiveRecord::Base
  has_many :memberships
  has_many :groups, through: :memberships
end

class Group < ActiveRecord::Base
  has_many :memberships
  has_many :users, through: :memberships
end

class Membership < ActiveRecord::Base
  belongs_to :user
  belongs_to :group
end

Memberships具有 数据库级别 外键约束，要求在创建Users和Groups之前先存在它们.但是，由于Rails按字母顺序加载夹具，因此Memberships在Users之前加载，并且会发生错误，指出该关系不存在(正确地如此).

Memberships have a database level foreign key constraint requiring Users and Groups to be present before they can be created. However, because Rails loads fixture alphabetically, Memberships are loaded before Users, and an error occurs stating the relationships do not exist (rightly so).

ActiveRecord::InvalidForeignKey: PG::ForeignKeyViolation: ERROR:  insert or update on table "memberships" violates foreign key constraint

在运行测试时，是否可以在加载Memberships之前先加载Users和Groups灯具?

Is there a way to load the Users and Groups fixtures before loading Memberships while running tests?

推荐答案

您的问题不是Rails运行测试的顺序.我遇到了与您相同的问题，经过几个小时的调试，我意识到ActiveRecord实际上确实在插入固定记录期间禁用了参照完整性，以防止Postgresql出现此类错误.

Your problem isn't the order that Rails is running your tests. I had the same issue as you, and after debugging for a few hours realized that ActiveRecord actually DOES disable referential integrity during insertion of fixture records to prevent these types of errors for Postgresql.

要注意的是，您的测试数据库用户必须在测试数据库上具有ActiveRecord的超级用户权限，才能成功禁用Fixture所需的参照完整性.

The catch is that your test database user must have superuser privileges on the test db for ActiveRecord to successfully disable referential integrity as needed for fixtures.

这是解决问题的方法:

1. 使用默认的超级用户(我的名字是"postgres")登录Postgresql

2. 执行以下命令:

1. Log into Postgresql with your default superuser (mine is "postgres")

2. Perform the following command:

ALTER ROLE yourtestdbuser WITH SUPERUSER;

享受工作正常的灯具.

Enjoy your properly working fixtures.

当一个人正在使用Postgresql运行一个测试数据库并且一个没有超级用户角色的用户运行时，Rails的下一发行版将发出警告(我认为这是非常需要的).我在 a Rails GitHub问题上提示警告.

The next release of Rails will have a warning (which I think is much needed) when a person is running a test database with Postgresql and a user without a superuser role. I found this on a Rails GitHub issue suggesting the warning.

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