Issues implementing Rspec with Rails3 from tutorial

I am a newbie to Rails 3 and Rspec. Kindly excuse my being a novice.

I am trying to implement RSpec with Rails 3. I am using Rails 3.0.3 with Ruby 1.9.2 on Ubuntu 10.04 os. I am using rspec 2.5 gem and rspec-rails 2.5 gem.

I am referring to the following tutorial:-

http://www.railsfire.com/article/rspec-behaviour-driven-development-testing-framework

This tutorial is implemented on Rails 2.x with an older version of rspec and rspec-rails.

I tried to implement exactly the same tutorial with my configuration, but I have run into some issues. I am unable to figure out what I must have done wrong.

I am sure about one thing that I am not using the rails_scaffold generator as used in this tutorial. Instead of using the rails_scaffold generator, I made use of the following command rails g scaffold post title:string body:text I don't seem to have it(rspec_scaffold) in my list of generators which as part of Rails 3 and the additional ones that will come with Rspec.

The error I am getting is :-

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 exp开发者_运维技巧ected 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$ 

Any suggestions on what I must be doing wrong and how to fix the same. Kindly help.

Thank you very much.

I made a fundamental mistake, I realized that I always made use of rake db:create, and rake db:migrate. This would set things for me with Development Environment. For the test enviroment, I had to use rake db:test:prepare or rake db:migrate with appropriate syntax to reflect the migrations in the Test Environment.