When you really want to test a private method, you can use this simple helper to temporarily expose it for easier access during specs.

expose_method.rb

require "spec_helper"

RSpec.describe MyClass do
  describe "#some_private_method" do
    expose_method MyClass, :some_private_method
    
    it "works" do
      MyClass.new.some_private_method
    end
  end
end

expose_private_methods.rb

# spec/support/expose_private_methods.rb
module ExposePrivateMethods
  # Note: does not work on protected methods
  def expose_method(klass, *methods)
    before { klass.send(:public, *methods) }
    after { klass.send(:private, *methods) }
  end
end

RSpec.configure do |config|
  config.extend ExposePrivateMethods
end