More hacks to handle zero dollar orders

I have a plan for how to handle these better in v1.0 though!

3 files changed, 20 insertions, 2 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b83f7af..5a6699c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,7 +2,7 @@
 
 ## master
 
-- Report no tax collected on order when order total zeroed out.
+- Report no tax collected on order and line items when order total zeroed out.
 
 ## v0.11.1
 
diff --git a/lib/super_good/solidus_taxjar/api_params.rb b/lib/super_good/solidus_taxjar/api_params.rb
index ca346ff..53b2c81 100644
--- a/lib/super_good/solidus_taxjar/api_params.rb
+++ b/lib/super_good/solidus_taxjar/api_params.rb
@@ -85,7 +85,7 @@ module SuperGood
                 product_tax_code: line_item.tax_category&.tax_code,
                 unit_price: line_item.price,
                 discount: discount(line_item),
-                sales_tax: line_item.additional_tax_total
+                sales_tax: line_item_sales_tax(line_item)
               }
             end
           }
@@ -112,6 +112,12 @@ module SuperGood
 
           order.additional_tax_total
         end
+
+        def line_item_sales_tax(line_item)
+          return 0 if line_item.order.total.zero?
+
+          line_item.additional_tax_total
+        end
       end
     end
   end
diff --git a/spec/super_good/solidus_taxjar/api_params_spec.rb b/spec/super_good/solidus_taxjar/api_params_spec.rb
index e16edb9..daa5b63 100644
--- a/spec/super_good/solidus_taxjar/api_params_spec.rb
+++ b/spec/super_good/solidus_taxjar/api_params_spec.rb
@@ -222,6 +222,18 @@ RSpec.describe SuperGood::SolidusTaxJar::APIParams do
       it "sends the sales tax total as zero" do
         expect(subject[:sales_tax]).to be_zero
       end
+
+      it "sends the sales tax on the line items as zero" do
+        expect(subject[:line_items]).to contain_exactly({
+          discount: 2,
+          id: line_item.id,
+          product_identifier: "G00D-PR0DUCT",
+          product_tax_code: "A_GEN_TAX",
+          quantity: 3,
+          sales_tax: 0,
+          unit_price: 10
+        })
+      end
     end
 
     context "when the line item has 0 quantity" do