4 files changed, 17 insertions, 10 deletions
diff --git a/lib/super_good/solidus_taxjar.rb b/lib/super_good/solidus_taxjar.rb
index ef9497d..818947d 100644
--- a/lib/super_good/solidus_taxjar.rb
+++ b/lib/super_good/solidus_taxjar.rb
@@ -26,6 +26,6 @@ module SuperGood
     }
     self.taxable_address_check = ->(address) { true }
     self.shipping_tax_label_maker = ->(shipment, shipping_tax) { "Sales Tax" }
-    self.line_item_tax_label_maker = ->(taxjar_line_item) { "Sales Tax" }
+    self.line_item_tax_label_maker = ->(taxjar_line_item, spree_line_item) { "Sales Tax" }
   end
 end
diff --git a/lib/super_good/solidus_taxjar/tax_calculator.rb b/lib/super_good/solidus_taxjar/tax_calculator.rb
index 91ff6c0..5052814 100644
--- a/lib/super_good/solidus_taxjar/tax_calculator.rb
+++ b/lib/super_good/solidus_taxjar/tax_calculator.rb
@@ -35,12 +35,18 @@ module SuperGood
 
       def line_item_taxes
         @line_item_taxes ||=
-          taxjar_breakdown.line_items.map do |line_item|
+          taxjar_breakdown.line_items.map do |taxjar_line_item|
+            spree_line_item_id = taxjar_line_item.id.to_i
+
+            # Searching in memory because this association is loaded and most
+            # orders aren't going to have a huge number of line items.
+            spree_line_item = order.line_items.find { |li| li.id == spree_line_item_id }
+
             Spree::Tax::ItemTax.new(
-              item_id: line_item.id.to_i,
-              label: line_item_tax_label(line_item),
+              item_id: spree_line_item_id,
+              label: line_item_tax_label(taxjar_line_item, spree_line_item),
               tax_rate: tax_rate,
-              amount: line_item.tax_collectable,
+              amount: taxjar_line_item.tax_collectable,
               included_in_price: false
             )
           end
@@ -141,8 +147,8 @@ module SuperGood
         )
       end
 
-      def line_item_tax_label(taxjar_line_item)
-        SuperGood::SolidusTaxJar.line_item_tax_label_maker.(taxjar_line_item)
+      def line_item_tax_label(taxjar_line_item, spree_line_item)
+        SuperGood::SolidusTaxJar.line_item_tax_label_maker.(taxjar_line_item, spree_line_item)
       end
     end
   end
diff --git a/spec/super_good/solidus_taxjar/tax_calculator_spec.rb b/spec/super_good/solidus_taxjar/tax_calculator_spec.rb
index 1899443..a13f564 100644
--- a/spec/super_good/solidus_taxjar/tax_calculator_spec.rb
+++ b/spec/super_good/solidus_taxjar/tax_calculator_spec.rb
@@ -24,7 +24,7 @@ RSpec.describe ::SuperGood::SolidusTaxJar::TaxCalculator do
       )
     end
 
-    let(:line_items) { [::Spree::LineItem.new] }
+    let(:line_items) { [::Spree::LineItem.new(id: 33)] }
 
     let(:boring_shipment) do
       ::Spree::Shipment.new(id: 1, cost: 7)
@@ -178,7 +178,7 @@ RSpec.describe ::SuperGood::SolidusTaxJar::TaxCalculator do
           before do
             allow(SuperGood::SolidusTaxJar.line_item_tax_label_maker)
               .to receive(:call)
-              .with(taxjar_line_item)
+              .with(taxjar_line_item, line_items.first)
               .and_return("Space Tax")
           end
 
diff --git a/spec/super_good/solidus_taxjar_spec.rb b/spec/super_good/solidus_taxjar_spec.rb
index 957e2e3..dafc4fb 100644
--- a/spec/super_good/solidus_taxjar_spec.rb
+++ b/spec/super_good/solidus_taxjar_spec.rb
@@ -45,8 +45,9 @@ RSpec.describe SuperGood::SolidusTaxJar do
     end
 
     describe ".line_item_tax_label_maker" do
-      subject { described_class.line_item_tax_label_maker.(taxjar_line_item) }
+      subject { described_class.line_item_tax_label_maker.(taxjar_line_item, spree_line_item) }
       let(:taxjar_line_item) { instance_double Taxjar::BreakdownLineItem }
+      let(:spree_line_item) { Spree::LineItem.new }
       it { is_expected.to eq "Sales Tax" }
     end
   end