Add RevRec attributes to shipping methods

Tests/Recurly/ShippingMethod_Test.php

@@ -0,0 +1,23 @@
+<?php
+
+class Recurly_ShippingMethodTest extends Recurly_TestCase
+{
+  function defaultResponses() {
+    return array(
+      array('GET', '/shipping_methods/fedex_ground', 'shipping_methods/show-200.xml'),
+    );
+  }
+
+  public function testPerformanceObligation() {
+    $shipping_method = Recurly_ShippingMethod::get('fedex_ground', $this->client);
+
+    $this->assertInstanceOf('Recurly_ShippingMethod', $shipping_method);
+    $this->assertEquals('fedex_ground', $shipping_method->code);
+    $this->assertEquals('FedEx Ground', $shipping_method->name);
+    $this->assertEquals('twywqfr48v9l', $shipping_method->liability_gl_account_id);
+    $this->assertEquals('thproqnpcuwp', $shipping_method->revenue_gl_account_id);
+    $this->assertEquals('4', $shipping_method->performance_obligation_id);
+    $this->assertInstanceOf('DateTime', $shipping_method->created_at);
+    $this->assertInstanceOf('DateTime', $shipping_method->updated_at);
+  }
+}

Tests/fixtures/shipping_methods/show-200.xml

@@ -0,0 +1,15 @@
+HTTP/1.1 200 OK
+Content-Type: application/xml; charset=utf-8
+
+<?xml version="1.0" encoding="UTF-8"?>
+<shipping_method href="https://api.recurly.com/v2/shipping_methods/fedex_ground">
+  <code>fedex_ground</code>
+  <name>FedEx Ground</name>
+  <accounting_code></accounting_code>
+  <liability_gl_account_id>twywqfr48v9l</liability_gl_account_id>
+  <revenue_gl_account_id>thproqnpcuwp</revenue_gl_account_id>
+  <performance_obligation_id>4</performance_obligation_id>
+  <tax_code></tax_code>
+  <created_at type="datetime">2019-05-07T16:36:22Z</created_at>
+  <updated_at type="datetime">2019-05-07T16:36:22Z</updated_at>
+</shipping_method>

lib/recurly/shipping_method.php

@@ -6,6 +6,9 @@
  * @property string $name The name of the shipping method.
  * @property string $accounting_code The accounting code of the shipping method.
  * @property string $tax_code The tax code of the shipping method.
+ * @property string $liability_gl_account_id The ID of the liability general ledger account associated with the plan.
+ * @property string $revenue_gl_account_id The ID of the revenue general ledger account associated with the plan.
+ * @property string $performance_obligation_id The ID of the performance obligation associated with the plan.
  * @property DateTime $created_at The date and time the shipping method was created.
  * @property DateTime $updated_at The date and time the shipping method was last updated.
  */