For when you want to stub class methods on a class that may or may not be loaded

gistfile1.rb

class SuperStubbedClass; end

class ClassStubber
  def self.stub!(class_string)
    classes = class_string.split('::')
    parent_klass = Object
    classes.each do |class_name|
      define_if_not_already(class_name, parent_klass)
      parent_klass = parent_klass.const_get(class_name)
    end
  end
  
  def self.unstub!(class_string)
    classes = class_string.split('::')
    parent_klass = Object
    classes.each do |class_name|
      if we_defined_class(class_name, parent_klass)
        parent_klass.send(:remove_const, class_name)
        return  #Only need to remove the highest class that we created (not its children)
      end
      parent_klass = parent_klass.const_get(class_name)
    end
  end
  
  def self.define_if_not_already(class_name, parent_klass)
    unless parent_klass.const_defined?(class_name)
      parent_klass.const_set(class_name, Class.new(SuperStubbedClass))
    end
  end
  
  def self.we_defined_class(class_name, parent_klass)
    constant = parent_klass.const_get(class_name)
    return false unless constant.is_a? Class  #It could be a module
    constant.superclass == SuperStubbedClass
  end
end

#########
# Usage #
#########

describe "Example" do

  stub_class_if_missing("User")  

  it "compiles" do
    user = stub
    User.stub(:find).with(1).and_return(user)
    User.find(1).should == user
  end

end