How to run rspec from the emacs shell?

Question

I'm following an entry-level tutorial on rspec here, and I've created a very simple test at spec\lib\zombie_spec.rb:

require "spec_helper"
describe "A Zombie" do
  #Your 'examples' (tests) go here.
  it "is named Ash"
end

If I run this test from the gnome-terminal, everything works as expected:

Pending: (Failures listed here are expected and do not affect your suite's status)

  1) A Zombie is named Ash
     # Not yet implemented
     # ./spec/lib/zombie_spec.rb:4


Finished in 0.00049 seconds (files took 0.09118 seconds to load)
1 example, 0 failures, 1 pending

However, if I try to run the same code from emacs' shell or ansi-term, I get this:

The program 'rspec' is currently not installed. You can install it by typing:
sudo apt install ruby-rspec-core

After installing ruby-rspec-core and trying to run the test again, I get this:

/home/adc/odin-project/web-development-101/20-code-school-rspec/zombie/spec/spec_helper.rb:48:in `block in <top (required)>': undefined method `shared_context_metadata_behavior=' for #<RSpec::Core::Configuration:0x00000000eed1d0> (NoMethodError)
    from /usr/lib/ruby/vendor_ruby/rspec/core.rb:97:in `configure'
    from /home/adc/odin-project/web-development-101/20-code-school-rspec/zombie/spec/spec_helper.rb:19:in `<top (required)>'
    from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /usr/lib/ruby/vendor_ruby/rspec/core/configuration.rb:1295:in `block in requires='
    from /usr/lib/ruby/vendor_ruby/rspec/core/configuration.rb:1295:in `each'
    from /usr/lib/ruby/vendor_ruby/rspec/core/configuration.rb:1295:in `requires='
    from /usr/lib/ruby/vendor_ruby/rspec/core/configuration_options.rb:109:in `block in process_options_into'
    from /usr/lib/ruby/vendor_ruby/rspec/core/configuration_options.rb:108:in `each'
    from /usr/lib/ruby/vendor_ruby/rspec/core/configuration_options.rb:108:in `process_options_into'
    from /usr/lib/ruby/vendor_ruby/rspec/core/configuration_options.rb:21:in `configure'
    from /usr/lib/ruby/vendor_ruby/rspec/core/runner.rb:105:in `setup'
    from /usr/lib/ruby/vendor_ruby/rspec/core/runner.rb:92:in `run'
    from /usr/lib/ruby/vendor_ruby/rspec/core/runner.rb:78:in `run'
    from /usr/lib/ruby/vendor_ruby/rspec/core/runner.rb:45:in `invoke'
    from /usr/bin/rspec:4:in `<main>'

How can I fix this so that rspec runs successfully from within the emacs shell?

Answer 1

It turns out this was a problem with ruby gems as a whole, not just rspec. And there's an emacs package that fixes the problem: rvm, as outlined here.

So, a step by step solution:

M-x package-install
rvm
M-x rvm-use-default

You can also add (rvm-use-default) to your init file to enable the package from startup.