我正在尝试使用Rails 7来创建测试数据库：

bin/rails db:test:prepare RAILS_ENV=test

我已经非常清楚地在database.yml中设置了测试环境：

default: &default
  adapter: postgresql
  encoding: utf8
  port:     5432
  pool:     5
  host:     localhost
  database: my_db_dev
  username: user
  password: pwd

development:
  <<: *default

test:
  <<: *default
  database: my_db_test

production:
  <<: *default

但命令试图删除我的开发数据库：

base) ➜  git:(main) ✗ bin/rails db:test:prepare RAILS_ENV=test
rails aborted!
ActiveRecord::StatementInvalid: PG::ObjectInUse: ERROR:  database "my_db_dev" is being accessed by other users
DETAIL:  There are 3 other sessions using the database.

Caused by:
PG::ObjectInUse: ERROR:  database "my_db_dev" is being accessed by other users
DETAIL:  There are 3 other sessions using the database.

Tasks: TOP => db:test:load => db:test:purge
(See full trace by running task with --trace)

关于环境设置，我遗漏了什么？我甚至运行了：

bin/rails db:environment:set RAILS_ENV=test

但似乎没什么效果。