stuck in rvm hell trying to get a simple rspec running

Question

Ruby Settings From terminal

 % ruby -v
ruby 1.9.2p180 (2011-02-18 revision 30909) [i686-linux]
=> ~/ruby/grounded/test
 % where ruby
/home/mike/.rvm/rubies/ruby-1.9.2-p180/bin/ruby
/home/mike/.rvm/bin/ruby
/usr/local/bin/ruby
/usr/bin/ruby
=> ~/ruby/grounded/Person/test
 % which ruby
/home/mike/.rvm/rubies/ruby-1.9.2-p180/bin/ruby
% rvm current
ruby-1.9.2-p180

Directory Structure

 % tree
.
├── bowling.rb
└── bowling_spec.rb

File Contents

bowling.rb

class Bowling

end

bowling_spec.rb

require 'rubygems'
require 'rspec'
require 'bowling'
describe Bowling, "#score" do
  it "returns 0 for all gutter game" do
    bowling = Bowling.new
    20.times { bowling.hit(0) }
    bowling.score.should eq(0)
  end
end

% ruby bowling_spec.rb

/home/mike/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require': no such file to load -- bowling (LoadError)
    from /home/mike/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
    from bowling_spec.rb:3:in `<main>'

Questions

• Why am I getting a LoadError when bowling.rb and bowling_spec.rb are in the same folder?
• In the error what the heck is .../site_ruby/1.9.1/... when I am running ruby 1.9.2 then why would 1.9.1 even show up?
• how do I get over this hump and start having fun with ruby.

Answer 1

When you require a file and don't specify an absolutely path to the file, Ruby looks on its load path (accessed within ruby as $LOAD_PATH or $:) and checks each directory there for the file you want. You cannot load bowling.rb because it's not in a directory on your load path.

The solution is one of two things:

1. Put the current directory on the load path:

   $:.unshift File.expand_path('.')
   

   This puts the full path to the current working directory on the load path.

2. Use require with the absolute path to the file:

   require File.expand_path('../bowling', __FILE__)
   

A little additional info: File.expand_path returns the absolute path to the first parameter from the current working directory, unless a second parameter is given; then it uses that as the starting point. So the whole line could be read:

require /home/mike/src/something/bowling_spec.rb/../bowling

Answer 2

When requiring files, the file must be in a list of directories called the $LOAD_PATH. The current directory used to be in this list, but as of 1.9.2, it has been removed for security reasons.

You have four options (listed in order of how good I think they are)

1 Change your directory structure to look like this

.
|-- lib
|   `-- bowling.rb
`-- spec
    `-- bowling_spec.rb

And then run as rspec spec instead of ruby bowling_spec.rb This works because RSpec will see that lib is in your current directory, and then add it to the $LOAD_PATH for you.

If you do this, you also don't have to require 'rspec'.

2 Run with ruby -I . bowling_spec.rb

which will add the current directory to the $LOAD_PATH

3 Use require_relative 'bowling' instead of require 'bowling'.

This will look for the bowling.rb file relative to the current file being run (bowling_spec.rb)

4 Use require('../bowling', __FILE__) instead of require 'bowling'

This is basically the same as the above.

Other questions:

Q: Why am I getting a LoadError when bowling.rb and bowling_spec.rb are in the same folder?

A: Because the current directory (the directory you are running the script from, not the directory the files are located in) is not in the $LOAD_PATH.

Q: In the error what the heck is .../site_ruby/1.9.1/... when I am running ruby 1.9.2 then why would 1.9.1 even show up?

A: Hmm. Not sure I remember exactly, but IIRC, it was something like they're so similar that the interface hadn't changed, so they could be compatible with 1.9.1 from a system perspective.

Q: how do I get over this hump and start having fun with ruby.

A: I suppose that depends. If the issue is that you want to be able to run files that are in your CWD, then you can add the environment variable RUBYLIB to . to your .bash_profile (or whatever the equivalent is on your system) which will tell Ruby to look in the current directory for files. This is prone to bugs, though (and it could lead to unintentional execution of Ruby files, which is a security risk). If you just mean "how do I start learning" or whats a fun project? Then check out one of my projects, Ruby Kickstart which, in six sessions, will take you through a pretty big portion of Ruby, and have you write and deploy a simple web app by the end of it.