Include API version in request headers

TaxJar requires certified extensions to include an API version in the
header of each request. This extensions wraps the official TaxJar Ruby
Gem with another API client, so we make sure the version gets set in
when our wrapper class is constructed.

Co-authored-by: Noah Silvera <noah@super.gd>

3 files changed, 21 insertions, 1 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index be3cc4d..75cdefb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 - [#21](https://github.com/SuperGoodSoft/solidus_taxjar/pull/21) Migrated project to `solidus_dev_support`
 - [#22](https://github.com/SuperGoodSoft/solidus_taxjar/pull/22) Added support for TaxJar address validation API through `SuperGood::SolidusTaxJar::Addresses` class
+- [#34](https://github.com/SuperGoodSoft/solidus_taxjar/pull/34) Include API version in request headers
 
 ## v0.17.1
 
diff --git a/lib/super_good/solidus_taxjar/api.rb b/lib/super_good/solidus_taxjar/api.rb
index 9a8ba90..a1d1af5 100644
--- a/lib/super_good/solidus_taxjar/api.rb
+++ b/lib/super_good/solidus_taxjar/api.rb
@@ -5,7 +5,9 @@ module SuperGood
         ::Taxjar::Client.new(
           api_key: ENV.fetch("TAXJAR_API_KEY"),
           api_url: ENV.fetch("TAXJAR_API_URL") { "https://api.taxjar.com" } # Sandbox URL: https://api.sandbox.taxjar.com
-        )
+        ).set_api_config('headers', {
+          'x-api-version' => '2020-08-07'
+        })
       end
 
       def initialize(taxjar_client: self.class.default_taxjar_client)
diff --git a/spec/super_good/solidus_taxjar/api_spec.rb b/spec/super_good/solidus_taxjar/api_spec.rb
index 7fab505..0244536 100644
--- a/spec/super_good/solidus_taxjar/api_spec.rb
+++ b/spec/super_good/solidus_taxjar/api_spec.rb
@@ -1,6 +1,23 @@
 require "spec_helper"
 
 RSpec.describe SuperGood::SolidusTaxJar::API do
+  describe ".new" do
+    subject { described_class.new }
+
+    let(:dummy_client) { instance_double ::Taxjar::Client }
+
+    before do
+      ENV["TAXJAR_API_KEY"] = 'taxjar_api_token'
+    end
+
+    it "puts the API version in the header" do
+      expect_any_instance_of(::Taxjar::Client).to receive(:set_api_config).with('headers', {
+        'x-api-version' => '2020-08-07'
+      })
+      subject
+    end
+  end
+
   describe "#tax_for" do
     subject { api.tax_for order }