Rails 3和update_attribute上的奇怪关系行为 [英] Weird relationship behavior on Rails 3 and update_attribute
问题描述
我很难找出测试失败的原因:
I'm having a hard time trying to find out why a test is failing:
describe User, "Instance Methods" do
describe "leave_group!" do
it "should set group_id to nil" do
@user = Factory(:user)
@group_2 = Factory(:group, :owner => @user)
@user.leave_group!
@user.reload.group_id.should be_nil # THIS LINE IS FAILING!!!
end
it "should assign another owner to group, if owner was user" do
@user = Factory(:user)
@group = Factory(:group, :owner => @user)
1.upto(4) { @group.add_user Factory(:user) }
@user.leave_group!
@group.reload.owner.should_not eql(@user)
end
end
end
这些是我正在使用的模型:
These are the models I'm using:
class User < ActiveRecord::Base
# Associations
has_one :own_group, :class_name => "Group", :foreign_key => "owner_id"
belongs_to :group
def leave_group!
current_group_id, current_group_owner = self.group.id, self.group.owner
self.group_id = nil
save!
Group.find(current_group_id).randomize_owner! if current_group_owner == self
end
end
class Group < ActiveRecord::Base
# Associations
has_many :users
belongs_to :owner, class_name: "User"
def randomize_owner!
current_users = self.users
return false unless current_users.length > 1
begin
new_user = current_users.sort_by { rand }.first
end while self.owner == new_user
self.owner_id = new_user.id
save!
end
end
我在这里做错什么了吗?我可以改善吗?更重要的是，为什么单个测试失败?
Am I doing something wrong here? Could I improve it? And more importantly, why is that single test failing?
这是运行单个测试的日志输出:
Here's the log output for runing that single test:
SQL (0.2ms) SELECT name
FROM sqlite_master
WHERE type = 'table' AND NOT name = 'sqlite_sequence'
AREL (0.3ms) INSERT INTO "users" ("name", "uid", "provider", "email", "image_url", "group_id", "created_at", "updated_at", "timezone", "public_readings", "is_visible_on_leaderboards", "phone_number") VALUES ('John Doe', '314159265', 'facebook', 'john@does.com', NULL, NULL, '2011-07-18 02:02:08.455229', '2011-07-18 02:02:08.455229', NULL, 't', 't', NULL)
Group Load (0.1ms) SELECT "groups".* FROM "groups" WHERE "groups"."key" = 'SNYEMJ' LIMIT 1
AREL (0.1ms) INSERT INTO "groups" ("name", "key", "score", "owner_id", "created_at", "updated_at") VALUES ('John''s Group', 'SNYEMJ', 0, 1, '2011-07-18 02:02:08.522442', '2011-07-18 02:02:08.522442')
AREL (0.0ms) UPDATE "users" SET "group_id" = 1, "updated_at" = '2011-07-18 02:02:08.524342' WHERE "users"."id" = 1
Group Load (0.1ms) SELECT "groups".* FROM "groups" WHERE "groups"."id" = 1 LIMIT 1
User Load (0.2ms) SELECT "users".* FROM "users" WHERE ("users".group_id = 1)
User Load (0.2ms) SELECT "users".* FROM "users" WHERE "users"."id" = 1 LIMIT 1
最后3行全都是选择，注意rails甚至没有尝试从用户中删除group_id. (有2个插入，其中1个用于测试用户，1个用于测试组，以及1个将group_id分配给测试用户的更新.)
The last 3 lines are all selects, notice rails doesn't even try to remove the group_id from the user. (There are 2 inserts, 1 for the test user and 1 for the test group and 1 update which assigns group_id to the test user).
推荐答案
尝试在测试中的@user.leave_group之前添加@user.reload调用.
Try adding a @user.reload call before @user.leave_group in the test.
即使从工厂创建@group_2时，用户记录在数据库中已更新为数据库中的组，但我怀疑@user对象不是.然后用@user和group ID为nil调用leave_group!，因此保存不会执行任何操作，因为对象未更改.然后，在测试的下一行中，重新加载@user，现在已从先前分配的数据库中添加了group_id.
Even though the user record is updated with it's group in the DB when you create @group_2 from the factory, I suspect the @user object is not. Then you call leave_group! with a @user with a group ID of nil, so the save won't do anything because the object is unchanged. Then in the next line of your test you reload the @user, which now has the group_id from the DB assigned earlier.
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