我是 Rails 3 和 Rspec 的新手。请原谅我是新手。
我正在尝试使用 Rails 3 实现 RSpec。我在 Ubuntu 10.04 操作系统上使用 Rails 3.0.3 和 Ruby 1.9.2。我正在使用 rspec 2.5 gem 和 rspec-rails 2.5 gem。
我指的是以下教程：-
http://www.railsfire.com/article/rspec-behaviour-driven-development-testing-framework
本教程是在 Rails 2.x 上使用旧版本的 rspec 和 rspec-rails 实现的。
我试图用我的配置实现完全相同的教程，但我遇到了一些问题。我无法弄清楚我一定做错了什么。
我确信我没有使用rails_scaffold本教程中使用的生成器。我没有使用生成器，而是rails_scaffold使用了以下命令rails g scaffold post title:string body:text
，我的生成器列表中似乎没有它（rspec_scaffold），它是 Rails 3 的一部分以及 Rspec 附带的其他生成器。
我得到的错误是： -
mohnish@mohnish-desktop:~/rails_testing/10Mar11/rspec_demo5$ rake spec
(in /home/mohnish/rails_testing/10Mar11/rspec_demo5)
rake aborted!
You have a nil object when you didn't expect it!
You might have expected an instance of ActiveRecord::Base.
The error occurred while evaluating nil.[]
(See full trace by running task with --trace)
mohnish@mohnish-desktop:~/rails_testing/10Mar11/rspec_demo5$ rake spec --trace
(in /home/mohnish/rails_testing/10Mar11/rspec_demo5)
** Invoke spec (first_time)
** Invoke db:test:prepare (first_time)
** Invoke db:abort_if_pending_migrations (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute db:abort_if_pending_migrations
** Execute db:test:prepare
** Invoke db:test:load (first_time)
** Invoke db:test:purge (first_time)
** Invoke environment
** Execute db:test:purge
rake aborted!
You have a nil object when you didn't expect it!
You might have expected an instance of ActiveRecord::Base.
The error occurred while evaluating nil.[]
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/railties/databases.rake:429:in `block (3 levels) in <top (required)>'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:636:in `call'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:636:in `block in execute'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:631:in `each'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:631:in `execute'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:597:in `block in invoke_with_call_chain'
/home/mohnish/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:607:in `block in invoke_prerequisites'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:604:in `each'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:604:in `invoke_prerequisites'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:596:in `block in invoke_with_call_chain'
/home/mohnish/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:583:in `invoke'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/activerecord-3.0.3/lib/active_record/railties/databases.rake:460:in `block (3 levels) in <top (required)>'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:636:in `call'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:636:in `block in execute'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:631:in `each'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:631:in `execute'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:597:in `block in invoke_with_call_chain'
/home/mohnish/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:607:in `block in invoke_prerequisites'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:604:in `each'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:604:in `invoke_prerequisites'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:596:in `block in invoke_with_call_chain'
/home/mohnish/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:583:in `invoke'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:2051:in `invoke_task'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:2029:in `block (2 levels) in top_level'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:2029:in `each'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:2029:in `block in top_level'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:2001:in `block in run'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/lib/rake.rb:1998:in `run'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/gems/rake-0.8.7/bin/rake:31:in `<top (required)>'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/bin/rake:19:in `load'
/home/mohnish/.rvm/gems/ruby-1.9.2-p180/bin/rake:19:in `<main>'
mohnish@mohnish-desktop:~/rails_testing/10Mar11/rspec_demo5$
关于我必须做错什么以及如何解决的任何建议。请帮忙。
非常感谢。