delicious_part.rb

# The problem:
# I wanted to test check_gem, which needs to be called
# in the initializer (well, *I* need it to be called in
# the initializer)
#
class Delicious < Base
  
  def initialize username, password
    check_gem
    # ...
  end
  def check_gem
    require 'www/delicious'
  rescue LoadError
    puts "..." # Gem missing message omitted.
    exit 1
  end

# ...

# I could of course initialize an instance, stub
# require and call check_gem again. But this is
# not the way to go. 

delicious_spec_part.rb

class DeliciousMock < Delicious
  def received_calls
    @received_calls ||= []
  end

  def require(name)
    raise LoadError
  end

  def puts(*args)
    received_calls << [:puts, args]
  end

  def exit(code)
    received_calls << [:exit, code]
  end
end

describe "check_gem" do
  before(:each) do
    @source = DeliciousMock.new
  end

  context "doesn't find www/delicious" do
    it "puts and exits with error" do
      @source.received_calls.should include([:puts, "..."])
      @source.received_calls.should include([:exit, 1])
    end
    # ... more specs