如果运行rspec的时候出现了Could not find table,你需要rake db:test:prepare.
如果你的数据库用的是sqlite3,测试的时候用的数据库并不是development.sqlite3,而是test.sqlite3,看其执行过程:
rake db:test:prepare --trace
** Invoke db:test:prepare (first_time)
** Invoke db:abort_if_pending_migrations (first_time)
** Invoke environment (first_time)
** Execute environment
** Invoke db:load_config (first_time)
** Execute db:load_config
** Execute db:abort_if_pending_migrations
** Execute db:test:prepare
** Invoke db:test:load (first_time)
** Invoke db:test:purge (first_time)
** Invoke environment
** Invoke db:load_config
** Execute db:test:purge
** Execute db:test:load
** Invoke db:test:load_schema (first_time)
** Invoke db:test:purge
** Execute db:test:load_schema
** Invoke db:schema:load (first_time)
** Invoke environment
** Invoke db:load_config
** Execute db:schema:load