is_it_inheritance.rb

class Payload
  def general_payload
    payload = Hash.new
    payload['PayloadVersion'] = 1
    payload['PayloadUUID'] = rand(10)
    payload['PayloadOrganization'] = organization
    payload
  end
end

class WebclipPayload < Payload
  attr_accessor :url, :identifier, :display_name, :description, :icon, :label, :organization
 
  def initialize(profile)
    @profile = profile
  end
  
  def payload
    content_payload = general_payload
    content_payload['PayloadIdentifier'] = @profile.identifier + ".webclip.intranet"
    content_payload['PayloadType'] = "com.apple.webClip.managed"
    content_payload
  end
end

class Profile < Payload
  attr_accessor :identifier, :display_name, :description, :organization
  
  def initialize(args = nil)
    @organization = "ProMDM"
    @identifier = "net.promdm"
    @payloads = []
  end
 
  def add_webclip
    webclip = WebclipPayload.new(self)
    webclip.identifier = identifier
    webclip.organization = organization
    webclip.display_name = "iOS Enrolled Webclip"
    @payloads << webclip
    return self
  end
  
  def add_other_payload
    # add some other payload
    # ...
  end
  
  def content
    payload = general_payload
    payload['PayloadType'] = "Configuration" # do not modify
    payload['PayloadIdentifier'] = identifier + ".encrypted-profile-service"
    payload['PayloadContent'] = @payloads.map(&:payload)
    payload
  end
end


# dump:
p Profile.new.add_webclip.content

or_mixin.rb

module GeneralPayloadHelper

  def general_payload
    payload = Hash.new
    payload['PayloadVersion'] = 1
    payload['PayloadUUID'] = rand(100
    payload['PayloadOrganization'] = organization
    payload['PayloadDisplayName'] = display_name
    payload['PayloadDescription'] = description
    payload
  end
end

class WebclipPayload
  attr_accessor :url, :identifier, :display_name, :description, :icon, :label, :organization
  
  include GeneralPayloadHelper
 
  def initialize(profile)
    @profile = profile
  end
  
  def payload
    content_payload = general_payload
    content_payload['PayloadIdentifier'] = @profile.identifier + ".webclip.intranet"
    content_payload['PayloadType'] = "com.apple.webClip.managed"
    content_payload
  end
end

class Profile
  attr_accessor :identifier, :display_name, :description, :organization
  
  include GeneralPayloadHelper
  
  def initialize(args = nil)
    @organization = "ProMDM"
    @identifier = "net.promdm"
    @payloads = []
  end
 
  def add_webclip
    webclip = WebclipPayload.new(self)
    webclip.identifier = identifier
    webclip.organization = organization
    webclip.display_name = "iOS Enrolled Webclip"
    @payloads << webclip
    return self
  end
  
  def add_other_payload
    # add some other payload
    # ...
  end
  
  def content
    payload = general_payload
    payload['PayloadType'] = "Configuration" # do not modify
    payload['PayloadIdentifier'] = identifier + ".encrypted-profile-service"
    payload['PayloadContent'] = @payloads.map(&:payload)
    payload
  end
end

p Profile.new.add_webclip.content

test_spec.rb

require 'rails_helper'

RSpec.describe GeneralPayloadHelper do
  
  before(:each) do
    @dummy_class = Struct.new(:organization, :display_name, :description).include(GeneralPayloadHelper).new
    @dummy_class.organization = "dummy"
  end

  it "returns general payload hash" do
    gp = @dummy_class.general_payload
    expect(gp).to be_kind_of(Hash)
    expect(gp["PayloadVersion"]).to eq(1)
    expect(gp["PayloadOrganization"]).to eq("dummy")
    # etc ...
  end

end