Communicate with TaxJar API

This allows us to calculate the tax for a Solidus order using the TaxJar
API. It's currently hardcoded to use the sandbox, and provides no
caching.

3 files changed, 168 insertions, 0 deletions

diff --git a/lib/super_good/solidus_taxjar.rb b/lib/super_good/solidus_taxjar.rb
index 6553213..40df3ec 100644
--- a/lib/super_good/solidus_taxjar.rb
+++ b/lib/super_good/solidus_taxjar.rb
@@ -8,4 +8,5 @@ module SuperGood
 end
 
 require "super_good/solidus_taxjar/version"
+require "super_good/solidus_taxjar/api"
 require "super_good/solidus_taxjar/tax_calculator"
diff --git a/lib/super_good/solidus_taxjar/api.rb b/lib/super_good/solidus_taxjar/api.rb
new file mode 100644
index 0000000..5434aab
--- /dev/null
+++ b/lib/super_good/solidus_taxjar/api.rb
@@ -0,0 +1,49 @@
+module SuperGood
+  module SolidusTaxJar
+    class API
+      def self.default_taxjar_client
+        ::Taxjar::Client.new(
+          api_key: ENV.fetch("TAXJAR_API_KEY"),
+          api_url: 'https://api.sandbox.taxjar.com'
+        )
+      end
+
+      def initialize(taxjar_client: Client.default_taxjar_client)
+        @taxjar_client = taxjar_client
+      end
+
+      def order_tax_for(order)
+        taxjar_client.tax_for_order order_params(order)
+      end
+
+      private
+
+      attr_reader :taxjar_client
+
+      def order_params(order)
+        ship_address = order.ship_address
+
+        {
+          to_country: ship_address.country.iso,
+          to_zip: ship_address.zipcode,
+          to_city: ship_address.city,
+          to_state: ship_address&.state&.abbr || ship_address.state_name,
+          to_street: ship_address.address1,
+
+          amount: order.item_total,
+          shipping: order.shipment_total,
+
+          line_items: order.line_items.map do |line_item|
+            {
+              id: line_item.id,
+              quantity: line_item.quantity,
+              unit_price: line_item.price,
+              discount: -line_item.adjustment_total,
+              product_tax_code: line_item.tax_category&.tax_code
+            }
+          end
+        }
+      end
+    end
+  end
+end
diff --git a/spec/super_good/solidus_taxjar/api_spec.rb b/spec/super_good/solidus_taxjar/api_spec.rb
new file mode 100644
index 0000000..ce49dd3
--- /dev/null
+++ b/spec/super_good/solidus_taxjar/api_spec.rb
@@ -0,0 +1,118 @@
+require 'spec_helper'
+
+RSpec.describe SuperGood::SolidusTaxJar::API do
+  describe "#order_tax_for" do
+    subject { api.order_tax_for order }
+
+    let(:api) do
+      described_class.new(taxjar_client: dummy_client)
+    end
+
+    let(:dummy_client) do
+      instance_double ::Taxjar::Client
+    end
+
+    let(:order) do
+      Spree::Order.create!(
+        item_total: 28.00,
+        shipment_total: 3.01,
+        ship_address: ship_address,
+        line_items: [line_item]
+      )
+    end
+
+    let(:ship_address) do
+      Spree::Address.create!(
+        country: country_us,
+        state: state_california,
+        zipcode: "90210",
+        city: "Los Angeles",
+        address1: "475 N Beverly Dr",
+
+        first_name: "Chuck",
+        last_name: "Schuldiner",
+        phone: "1-250-555-4444"
+      )
+    end
+
+    let(:country_us) do
+      Spree::Country.create!(
+        iso_name: "UNITED STATES",
+        iso: "US",
+        iso3: "USA",
+        name: "United States",
+        numcode: 840,
+        states_required: true
+      )
+    end
+
+    let(:state_california) do
+      Spree::State.create!(
+        country: country_us,
+        name: "California",
+        abbr: "CA"
+      )
+    end
+
+    let(:line_item) do
+      Spree::LineItem.new(
+        variant: variant,
+        price: 10,
+        quantity: 3,
+        adjustment_total: -2
+      )
+    end
+
+    let(:variant) do
+      Spree::Variant.create!(
+        product: product,
+        price: 10
+      )
+    end
+
+    let(:product) do
+      Spree::Product.create!(
+        name: "Product Name",
+        shipping_category: shipping_category,
+        tax_category: Spree::TaxCategory.first,
+        master: master_variant,
+        variants: [master_variant]
+      )
+    end
+
+    let(:shipping_category) do
+      Spree::ShippingCategory.create!(name: "Default Category")
+    end
+
+    let(:master_variant) do
+      Spree::Variant.new(
+        is_master: true,
+        price: 10
+      )
+    end
+
+    before do
+
+      allow(dummy_client).to receive(:tax_for_order).with(
+        to_country: "US",
+        to_zip: "90210",
+        to_city: "Los Angeles",
+        to_state: "CA",
+        to_street: "475 N Beverly Dr",
+
+        amount: 28.00,
+        shipping: 3.01,
+
+        line_items: [{
+          id: order.line_items.first.id,
+          quantity: 3,
+          unit_price: 10.00,
+          discount: 2.00,
+          product_tax_code: "A_GEN_TAX"
+        }]
+      ).and_return({ some_kind_of: "response" })
+    end
+
+    it { is_expected.to eq({ some_kind_of: "response" }) }
+  end
+end