--- /dev/null
+<?php
+
+namespace Drupal\KernelTests\Core\Render\Element;
+
+use Drupal\Core\Form\FormState;
+use Drupal\Core\Render\Element\Weight;
+use Drupal\KernelTests\KernelTestBase;
+
+/**
+ * @coversDefaultClass \Drupal\Core\Render\Element\Weight
+ * @group Render
+ */
+class WeightTest extends KernelTestBase {
+
+ /**
+ * {@inheritdoc}
+ */
+ protected static $modules = ['system'];
+
+ /**
+ * {@inheritdoc}
+ */
+ protected function setUp() {
+ parent::setUp();
+ $this->installConfig(['system']);
+ }
+
+ /**
+ * Test existing #default_value value in #options list.
+ *
+ * @covers ::processWeight
+ */
+ public function testProcessWeight() {
+ $element = [];
+ $form_state = new FormState();
+ $complete_form = [];
+
+ $element_object = new Weight([], 'weight', []);
+ $info = $element_object->getInfo();
+ $element += $info;
+
+ $element['#default_value'] = $element['#delta'] + 5;
+
+ Weight::processWeight($element, $form_state, $complete_form);
+
+ $this->assertTrue(
+ isset($element['#options'][$element['#default_value']]),
+ 'Default value exists in the #options list'
+ );
+ }
+
+}