Don't use mock_model in model test

We can just use the FactoryBot factories instead.

Co-Authored-By: Benjamin <benjamin@super.gd>
Co-Authored-By: Alistair <alistair@super.gd>

Author: 3 people

TODO.md

@@ -29,7 +29,7 @@ In-Memory Order Updater TODO
   - "This is really something which theoretically should be covered in tests"
 
 ## Mar 28, 2025
-- [ ] Verify if it is a breaking change to call
+- [x] Verify if it is a breaking change to call
   `LineItem#set_required_attributes` in `after_initialize` instead of
   `before_validation`. We think this may be a breaking change that requires
-  further investigation.
+  further investigation. (We investigated and don't believe it is a breaking change.)

promotions/spec/models/solidus_promotions/conditions/line_item_product_spec.rb

@@ -15,12 +15,11 @@
   describe "#eligible?(line_item)" do
     subject { condition.eligible?(line_item, {}) }
 
-    let(:condition_line_item) { Spree::LineItem.new(product: condition_product) }
-    let(:other_line_item) { Spree::LineItem.new(product: other_product) }
+    let(:condition_line_item) { build(:line_item, product: condition_product) }
+    let(:other_line_item) { build(:line_item) }
 
     let(:condition_options) { super().merge(products: [condition_product]) }
-    let(:condition_product) { mock_model(Spree::Product, tax_category: nil) }
-    let(:other_product) { mock_model(Spree::Product, tax_category: nil) }
+    let(:condition_product) { build(:product) }
 
     it "is eligible if there are no products" do
       expect(condition).to be_eligible(condition_line_item)

promotions/spec/models/solidus_promotions/conditions/product_spec.rb

@@ -188,12 +188,11 @@
   describe "#eligible?(line_item)" do
     subject { condition.eligible?(line_item) }
 
-    let(:condition_line_item) { Spree::LineItem.new(product: condition_product) }
-    let(:other_line_item) { Spree::LineItem.new(product: other_product) }
+    let(:condition_line_item) { build(:line_item, product: condition_product) }
+    let(:other_line_item) { build(:line_item) }
 
     let(:condition_options) { super().merge(products: [condition_product]) }
-    let(:condition_product) { mock_model(Spree::Product, tax_category: nil) }
-    let(:other_product) { mock_model(Spree::Product, tax_category: nil) }
+    let(:condition_product) { build(:product) }
 
     it "is eligible if there are no products" do
       expect(condition).to be_eligible(condition_line_item)