Add unit test for 'wc_get_price_excluding_tax'.

The test verifies that when an order is passed as an argument,
the order customer is passed to 'WC_Tax::get_rates'.

includes/wc-product-functions.php

@@ -9,6 +9,7 @@
  */
 
 use Automattic\Jetpack\Constants;
+use Automattic\WooCommerce\Proxies\LegacyProxy;
 use Automattic\WooCommerce\Utilities\ArrayUtil;
 use Automattic\WooCommerce\Utilities\NumberUtil;
 
@@ -1083,7 +1084,7 @@ function wc_get_price_excluding_tax( $product, $args = array() ) {
 
 	if ( $product->is_taxable() && wc_prices_include_tax() ) {
 		$order          = ArrayUtil::get_value_or_default( $args, 'order' );
-		$customer       = $order ? new WC_Customer( $order->get_customer_id() ) : null;
+		$customer       = $order ? wc_get_container()->get( LegacyProxy::class )->get_instance_of( WC_Customer::class, $order->get_customer_id() ) : null;
 		$tax_rates      = WC_Tax::get_rates( $product->get_tax_class(), $customer );
 		$base_tax_rates = WC_Tax::get_base_tax_rates( $product->get_tax_class( 'unfiltered' ) );
 		$remove_taxes   = apply_filters( 'woocommerce_adjust_non_base_location_prices', true ) ? WC_Tax::calc_tax( $line_price, $base_tax_rates, true ) : WC_Tax::calc_tax( $line_price, $tax_rates, true );

tests/legacy/mockable-functions.php

@@ -13,5 +13,6 @@ return array(
 	'get_woocommerce_currencies',
 	'get_woocommerce_currency_symbol',
 	'wc_get_shipping_method_count',
+	'wc_prices_include_tax',
 	'wc_site_is_https',
 );

tests/php/includes/wc-product-functions-test.php

@@ -0,0 +1,97 @@
+<?php
+/**
+ * Unit tests for wc-product-functions.php.
+ *
+ * @package WooCommerce\Tests\Functions\Stock
+ */
+
+use Automattic\WooCommerce\Testing\Tools\CodeHacking\Hacks\FunctionsMockerHack;
+use Automattic\WooCommerce\Testing\Tools\CodeHacking\Hacks\StaticMockerHack;
+
+/**
+ * Class WC_Stock_Functions_Tests.
+ */
+class WC_Product_Functions_Tests extends \WC_Unit_Test_Case {
+
+	/**
+	 * @testdox If 'wc_get_price_excluding_tax' gets an order as argument, it passes the order customer to 'WC_Tax::get_rates'.
+	 *
+	 * @testWith [true]
+	 *           [false]
+	 *
+	 * @param bool $pass_order Whether an order is passed to 'wc_get_price_excluding_tax' or not.
+	 */
+	public function test_wc_get_price_excluding_tax_passes_order_customer_to_get_rates_if_order_is_available( $pass_order ) {
+		$customer_passed_to_get_rates                  = false;
+		$customer_id_passed_to_wc_customer_constructor = false;
+
+		FunctionsMockerHack::add_function_mocks(
+			array(
+				'wc_prices_include_tax' => '__return_true',
+			)
+		);
+
+		StaticMockerHack::add_method_mocks(
+			array(
+				'WC_Tax' =>
+				array(
+					'get_rates'          => function( $tax_class, $customer ) use ( &$customer_passed_to_get_rates ) {
+						$customer_passed_to_get_rates = $customer;
+					},
+					'get_base_tax_rates' => function( $tax_class ) {
+						return 0;
+					},
+					'calc_tax'           => function( $price, $rates, $price_includes_tax = false, $deprecated = false ) {
+						return array( 0 );
+					},
+				),
+			)
+		);
+
+		// phpcs:disable Squiz.Commenting.FunctionComment.Missing
+
+		$product = new class() extends WC_Product {
+			public function get_price( $context = 'view' ) {
+				return 0;
+			}
+
+			public function is_taxable() {
+				return true;
+			}
+
+			public function get_tax_class( $context = 'view' ) {
+				return '';
+			}
+		};
+
+		$customer = new stdClass();
+		$this->register_legacy_proxy_class_mocks(
+			array(
+				'WC_Customer' => function( $customer_id ) use ( &$customer_id_passed_to_wc_customer_constructor, $customer ) {
+					$customer_id_passed_to_wc_customer_constructor = $customer_id;
+					return $customer;
+				},
+			)
+		);
+
+		if ( $pass_order ) {
+			$order = new class() {
+				public function get_customer_id() {
+					return 1;
+				}
+			};
+
+			wc_get_price_excluding_tax( $product, array( 'order' => $order ) );
+
+			$this->assertEquals( $order->get_customer_id(), $customer_id_passed_to_wc_customer_constructor );
+			$this->assertSame( $customer, $customer_passed_to_get_rates );
+		} else {
+			wc_get_price_excluding_tax( $product );
+
+			$this->assertFalse( $customer_id_passed_to_wc_customer_constructor );
+			$this->assertNull( $customer_passed_to_get_rates );
+		}
+
+		// phpcs:enable Squiz.Commenting.FunctionComment.Missing
+	}
+}