Expose WCPay refund transaction id for refund endpoint

changelog/add-transaction-id-to-refund-endpoint

@@ -0,0 +1,4 @@
+Significance: minor
+Type: add
+
+Expose WooCommerce transaction id for a refund on refund API endpoint

includes/class-wc-payment-gateway-wcpay.php

@@ -1877,6 +1877,7 @@ static function ( $refund ) use ( $refund_amount ) {
 		$wc_last_refund = WC_Payments_Utils::get_last_refund_from_order_id( $order_id );
 		if ( $wc_last_refund ) {
 			$this->order_service->set_wcpay_refund_id_for_order( $wc_last_refund, $refund['id'] );
+			$this->order_service->set_wcpay_transaction_id_for_order( $wc_last_refund, $refund['balance_transaction'] );
 			$wc_last_refund->save_meta_data();
 		}
 

includes/class-wc-payments-order-service.php

@@ -83,6 +83,13 @@ class WC_Payments_Order_Service {
 	 */
 	const WCPAY_REFUND_ID_META_KEY = '_wcpay_refund_id';
 
+	/**
+	 * Meta key used to store WCPay refund transaction id.
+	 *
+	 * @const string
+	 */
+	const WCPAY_TRANSACTION_ID_META_KEY = '_refund_transaction_id';
+
 	/**
 	 * Meta key used to store WCPay refund status.
 	 *
@@ -651,6 +658,20 @@ public function set_wcpay_refund_id_for_order( $order, $wcpay_refund_id ) {
 		$order->save_meta_data();
 	}
 
+	/**
+	 * Set the payment metadata for refund transaction id.
+	 *
+	 * @param  mixed  $order The order.
+	 * @param  string $wcpay_transaction_id The value to be set.
+	 *
+	 * @throws Order_Not_Found_Exception
+	 */
+	public function set_wcpay_transaction_id_for_order( $order, $wcpay_transaction_id ) {
+		$order = $this->get_order( $order );
+		$order->update_meta_data( self::WCPAY_TRANSACTION_ID_META_KEY, $wcpay_transaction_id );
+		$order->save_meta_data();
+	}
+
 	/**
 	 * Get the payment metadata for refund id.
 	 *

tests/unit/test-class-wc-payments-order-service.php

@@ -1155,6 +1155,12 @@ public function test_set_wcpay_refund_id() {
 		$this->assertEquals( $this->order->get_meta( '_wcpay_refund_id', true ), $wcpay_refund_id );
 	}
 
+	public function set_wcpay_transaction_id_for_order() {
+		$wcpay_refund_transaction_id = 'txn_mock';
+		$this->order_service->set_wcpay_transaction_id_for_order( $this->order, $wcpay_refund_transaction_id );
+		$this->assertSame( $this->order->get_meta( WC_Payments_Order_Service::WCPAY_TRANSACTION_ID_META_KEY, true ), $wcpay_refund_transaction_id );
+	}
+
 	public function test_get_wcpay_refund_id() {
 		$wcpay_refund_id = 'ri_1234';
 		$this->order->update_meta_data( '_wcpay_refund_id', $wcpay_refund_id );