Remove `dummy_order` and `dummy_line_item` helpers

These helpers are dangerous: they provide a false sense of assurance
by making you think that the order and the line item they return can
be used to infer the correct total value of future subscription orders.

In reality, order calculation in Solidus is an extremely complex process
that may take a ton of different parameters into account, and each store
is better off calculating the subscription total with their custom logic
rather than this extension trying to provide a solution that works for
everyone.

In the future, we may provide a way to compute a subscription's total,
but for the time being it's better to remove the helpers altogether.

10 files changed, 1 insertions, 222 deletions

diff --git a/README.md b/README.md
index 2705c2d..6c3ed60 100644
--- a/README.md
+++ b/README.md
@@ -62,8 +62,7 @@ This will associate a `SolidusSubscriptions::LineItem` to the line item being ad
 
 The customer will not be charged for the subscription until it is processed. The subscription line
 items should be shown to the user on the cart page by looping over
-`Spree::Order#subscription_line_items`. `SolidusSubscriptions::LineItem#dummy_line_item` may be
-useful to help you display the subscription line item with your existing cart infrastructure.
+`Spree::Order#subscription_line_items`.
 
 When the order is finalized, a `SolidusSubscriptions::Subscription` will be created for each group
 of subscription line items which can be fulfilled by a single subscription.
diff --git a/app/models/solidus_subscriptions/installment.rb b/app/models/solidus_subscriptions/installment.rb
index 0b5f627..aed1f62 100644
--- a/app/models/solidus_subscriptions/installment.rb
+++ b/app/models/solidus_subscriptions/installment.rb
@@ -31,13 +31,6 @@ module SolidusSubscriptions
       unfulfilled.where("#{table_name}.actionable_date <= ?", Time.zone.today)
     end)
 
-    # Get the builder for the subscription_line_item. This will be an
-    # object that can generate the appropriate line item for the subscribable
-    # object
-    #
-    # @return [SolidusSubscriptions::LineItemBuilder]
-    delegate :line_item_builder, to: :subscription
-
     # Mark this installment as out of stock.
     #
     # @return [SolidusSubscriptions::InstallmentDetail] The record of the failed
diff --git a/app/models/solidus_subscriptions/line_item.rb b/app/models/solidus_subscriptions/line_item.rb
index 64e6fb0..2583ecc 100644
--- a/app/models/solidus_subscriptions/line_item.rb
+++ b/app/models/solidus_subscriptions/line_item.rb
@@ -38,34 +38,5 @@ module SolidusSubscriptions
     validates :subscribable_id, presence: true
     validates :quantity, numericality: { greater_than: 0 }
     validates :interval_length, numericality: { greater_than: 0 }, unless: -> { subscription }
-
-    def as_json(**options)
-      options[:methods] ||= [:dummy_line_item]
-      super(options)
-    end
-
-    # Get a placeholder line item for calculating the values of future
-    # subscription orders. It is frozen and cannot be saved
-    def dummy_line_item
-      li = LineItemBuilder.new([self]).spree_line_items.first
-      return unless li
-
-      li.order = dummy_order
-      li.validate
-      li.freeze
-    end
-
-    private
-
-    # Get a placeholder order for calculating the values of future
-    # subscription orders. It is a frozen duplicate of the current order and
-    # cannot be saved
-    def dummy_order
-      order = spree_line_item ? spree_line_item.order.dup : ::Spree::Order.create
-      order.ship_address = subscription.shipping_address || subscription.user.ship_address if subscription
-      order.bill_address = subscription.billing_address || subscription.user.bill_address if subscription
-
-      order.freeze
-    end
   end
 end
diff --git a/app/models/solidus_subscriptions/subscription.rb b/app/models/solidus_subscriptions/subscription.rb
index 4168973..15424d8 100644
--- a/app/models/solidus_subscriptions/subscription.rb
+++ b/app/models/solidus_subscriptions/subscription.rb
@@ -203,15 +203,6 @@ module SolidusSubscriptions
       actionable_date
     end
 
-    # Get the builder for the subscription_line_item. This will be an
-    # object that can generate the appropriate line item for the subscribable
-    # object
-    #
-    # @return [SolidusSubscriptions::LineItemBuilder]
-    def line_item_builder
-      LineItemBuilder.new(line_items)
-    end
-
     # The state of the last attempt to process an installment associated to
     # this subscription
     #
diff --git a/lib/solidus_subscriptions.rb b/lib/solidus_subscriptions.rb
index a052504..d5e3d73 100644
--- a/lib/solidus_subscriptions.rb
+++ b/lib/solidus_subscriptions.rb
@@ -19,7 +19,6 @@ require 'solidus_subscriptions/churn_buster/subscription_payment_method_serializ
 require 'solidus_subscriptions/churn_buster/subscription_serializer'
 require 'solidus_subscriptions/churn_buster/order_serializer'
 require 'solidus_subscriptions/checkout'
-require 'solidus_subscriptions/line_item_builder'
 require 'solidus_subscriptions/subscription_generator'
 require 'solidus_subscriptions/subscription_line_item_builder'
 require 'solidus_subscriptions/dispatcher/base'
diff --git a/lib/solidus_subscriptions/line_item_builder.rb b/lib/solidus_subscriptions/line_item_builder.rb
deleted file mode 100644
index c9aedb9..0000000
--- a/lib/solidus_subscriptions/line_item_builder.rb
+++ /dev/null
@@ -1,36 +0,0 @@
-# frozen_string_literal: true
-
-# This class is responsible for taking SubscriptionLineItems and building
-# them into Spree::LineItems which can be added to an order
-module SolidusSubscriptions
-  class LineItemBuilder
-    attr_reader :subscription_line_items
-
-    # Get a new instance of a LineItemBuilder
-    #
-    # @param subscription_line_items[Array<SolidusSubscriptions::LineItem>] The
-    #   subscription line item to be converted into a Spree::LineItem
-    #
-    # @return [SolidusSubscriptions::LineItemBuilder]
-    def initialize(subscription_line_items)
-      @subscription_line_items = subscription_line_items
-    end
-
-    # Get a new (unpersisted) Spree::LineItem which matches the details of
-    # :subscription_line_item
-    #
-    # @return [Array<Spree::LineItem>]
-    def spree_line_items
-      line_items = subscription_line_items.map do |subscription_line_item|
-        variant = subscription_line_item.subscribable
-
-        next unless variant.can_supply?(subscription_line_item.quantity)
-
-        ::Spree::LineItem.new(variant: variant, quantity: subscription_line_item.quantity)
-      end
-
-      # Either all line items for an installment are fulfilled or none are
-      line_items.all? ? line_items : []
-    end
-  end
-end
diff --git a/spec/lib/solidus_subscriptions/line_item_builder_spec.rb b/spec/lib/solidus_subscriptions/line_item_builder_spec.rb
deleted file mode 100644
index d1e041c..0000000
--- a/spec/lib/solidus_subscriptions/line_item_builder_spec.rb
+++ /dev/null
@@ -1,33 +0,0 @@
-require 'spec_helper'
-
-RSpec.describe SolidusSubscriptions::LineItemBuilder do
-  let(:builder) { described_class.new subscription_line_items }
-  let(:variant) { create(:variant, subscribable: true) }
-  let(:subscription_line_item) { subscription_line_items.first }
-  let(:subscription_line_items) do
-    build_stubbed_list(:subscription_line_item, 1, subscribable_id: variant.id)
-  end
-
-  describe '#spree_line_items' do
-    subject { builder.spree_line_items }
-
-    let(:expected_attributes) do
-      {
-        variant_id: subscription_line_item.subscribable_id,
-        quantity: subscription_line_item.quantity
-      }
-    end
-
-    it { is_expected.to be_a Array }
-
-    it 'contains a line item with the correct attributes' do
-      expect(subject.first).to have_attributes expected_attributes
-    end
-
-    context 'the variant is out of stock' do
-      before { create :stock_location, backorderable_default: false }
-
-      it { is_expected.to be_empty }
-    end
-  end
-end
diff --git a/spec/models/solidus_subscriptions/installment_spec.rb b/spec/models/solidus_subscriptions/installment_spec.rb
index 4e4831e..399a7e6 100644
--- a/spec/models/solidus_subscriptions/installment_spec.rb
+++ b/spec/models/solidus_subscriptions/installment_spec.rb
@@ -5,15 +5,6 @@ RSpec.describe SolidusSubscriptions::Installment, type: :model do
 
   it { is_expected.to validate_presence_of :subscription }
 
-  describe '#line_item_builder' do
-    subject { installment.line_item_builder }
-
-    let(:line_items) { installment.subscription.line_items }
-
-    it { is_expected.to be_a SolidusSubscriptions::LineItemBuilder }
-    it { is_expected.to have_attributes(subscription_line_items: line_items) }
-  end
-
   describe '#out_of_stock' do
     subject { installment.out_of_stock }
 
diff --git a/spec/models/solidus_subscriptions/line_item_spec.rb b/spec/models/solidus_subscriptions/line_item_spec.rb
index ad80384..aaa24a5 100644
--- a/spec/models/solidus_subscriptions/line_item_spec.rb
+++ b/spec/models/solidus_subscriptions/line_item_spec.rb
@@ -24,90 +24,4 @@ RSpec.describe SolidusSubscriptions::LineItem, type: :model do
       expect(subject.from_now).to eq Date.parse("2016-10-22")
     end
   end
-
-  describe '#as_json' do
-    subject { line_item.as_json }
-
-    around { |e| Timecop.freeze { e.run } }
-
-    let(:line_item) { create(:subscription_line_item, :with_subscription) }
-
-    let(:expected_hash) do
-      hash = {
-        "id" => line_item.id,
-        "spree_line_item_id" => line_item.spree_line_item.id,
-        "subscription_id" => line_item.subscription_id,
-        "quantity" => line_item.quantity,
-        "end_date" => line_item.end_date,
-        "subscribable_id" => line_item.subscribable_id,
-        "created_at" => line_item.created_at,
-        "updated_at" => line_item.updated_at,
-        "interval_units" => line_item.interval_units,
-        "interval_length" => line_item.interval_length
-      }
-      Rails.gem_version >= Gem::Version.new('6.0.0') ? hash.as_json : hash
-    end
-
-    it 'includes the attribute values' do
-      expect(subject).to match a_hash_including(expected_hash)
-    end
-
-    it 'includes the dummy lineitem' do
-      expect(subject).to have_key('dummy_line_item')
-    end
-  end
-
-  describe '#dummy_line_item' do
-    subject { line_item.dummy_line_item }
-
-    let(:line_item) { create(:subscription_line_item, :with_subscription) }
-
-    it { is_expected.to be_a Spree::LineItem }
-    it { is_expected.to be_frozen }
-
-    it 'has the correct variant' do
-      expect(subject.variant_id).to eq line_item.subscribable_id
-    end
-
-    context 'with no spree line item' do
-      let(:line_item) { create(:subscription_line_item, :with_subscription, spree_line_item: nil) }
-
-      it { is_expected.to be_a Spree::LineItem }
-      it { is_expected.to be_frozen }
-
-      it 'has the correct variant' do
-        expect(subject.variant_id).to eq line_item.subscribable_id
-      end
-    end
-
-    context 'with an associated subscription' do
-      context 'the associated subscription has a shipping address' do
-        let(:line_item) do
-          create(:subscription_line_item, :with_subscription, subscription_traits: [:with_shipping_address])
-        end
-
-        it 'uses the subscription shipping address' do
-          expect(subject.order.ship_address).to eq line_item.subscription.shipping_address
-        end
-
-        it 'uses the subscription users billing address' do
-          expect(subject.order.bill_address).to eq line_item.subscription.user.bill_address
-        end
-      end
-
-      context 'the associated subscription has a billing address' do
-        let(:line_item) do
-          create(:subscription_line_item, :with_subscription, subscription_traits: [:with_billing_address])
-        end
-
-        it 'uses the subscription users shipping address' do
-          expect(subject.order.ship_address).to eq line_item.subscription.user.ship_address
-        end
-
-        it 'uses the subscription billing address' do
-          expect(subject.order.bill_address).to eq line_item.subscription.billing_address
-        end
-      end
-    end
-  end
 end
diff --git a/spec/models/solidus_subscriptions/subscription_spec.rb b/spec/models/solidus_subscriptions/subscription_spec.rb
index 5d855db..f305580 100644
--- a/spec/models/solidus_subscriptions/subscription_spec.rb
+++ b/spec/models/solidus_subscriptions/subscription_spec.rb
@@ -348,16 +348,6 @@ RSpec.describe SolidusSubscriptions::Subscription, type: :model do
     end
   end
 
-  describe '#line_item_builder' do
-    subject { subscription.line_item_builder }
-
-    let(:subscription) { create :subscription, :with_line_item }
-    let(:line_items) { subscription.line_items }
-
-    it { is_expected.to be_a SolidusSubscriptions::LineItemBuilder }
-    it { is_expected.to have_attributes(subscription_line_items: line_items) }
-  end
-
   describe '#processing_state' do
     subject { subscription.processing_state }