reverted:
--- b/tests/src/Unit/OrderItemTrackingTest.php
+++ a/tests/src/Unit/OrderItemTrackingTest.php
@@ -76,7 +76,7 @@
   /**
    * Data provider for ::testStorage.
    */
+  public function dataStorage() {
-  public static function dataStorage() {
     yield 'set-and-get' => [
       'set_order_id' => 10,
       'set_route_name' => 'commerce_checkout',
@@ -183,7 +183,7 @@
   /**
    * Data provider for ::testCalculate.
    */
+  public function dataCalculate() {
-  public static function dataCalculate() {
     yield 'no-existing' => [
       'total_price' => ['70.00', 'GBP'],
       'items' => [
@@ -404,7 +404,7 @@
   /**
    * Data provider for ::testValidate.
    */
+  public function dataValidate() {
-  public static function dataValidate() {
     yield 'no-tracking' => [
       'amount' => '10',
       'tracking' => NULL,