Nitin Lama
--- a/src/Element/Interval.php
+++ b/src/Element/Interval.php
   * Process callback.
   */
  public static function process(&$element, FormStateInterface $form_state, &$complete_form) {
-    $value = !empty($element['#default_value']) ? $element['#default_value'] : ['interval' => NULL, 'period' => NULL];
+    $value = !empty($element['#default_value']) ? $element['#default_value'] : [
+      'interval' => NULL,
+      'period' => NULL,
+    ];
--- a/src/Plugin/Field/FieldType/IntervalItem.php
+++ b/src/Plugin/Field/FieldType/IntervalItem.php
  /**
   * {@inheritdoc}
   */
-  public function buildPHPString() {
+  public function buildPhpString() {
--- a/tests/src/Functional/IntervalTest.php
+++ b/tests/src/Functional/IntervalTest.php
 */
 class IntervalTest extends BrowserTestBase {

+  use StringTranslationTrait;
--- a/tests/src/Functional/IntervalTest.php
+++ b/tests/src/Functional/IntervalTest.php
      'field_name' => 'foobar',
      'new_storage_type' => 'interval',
    ];
-    $this->submitForm($edit, t('Save and continue'));
+    $this->submitForm($edit, $this->t('Save and continue'));
--- a/tests/src/Functional/IntervalTest.php
+++ b/tests/src/Functional/IntervalTest.php
      'new_storage_type' => 'interval',
    ];
-    $this->submitForm($edit, t('Save and continue'));
+    $this->submitForm($edit, $this->t('Save and continue'));
    $this->submitForm([
      'cardinality' => FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED,
-    ], t('Save field settings'));
+    ], $this->t('Save field settings'));

-    $this->submitForm([], t('Save settings'));
-    $this->assertSession()->responseContains(t('Saved %name configuration', ['%name' => 'Foobar']));
+    $this->submitForm([], $this->t('Save settings'));
+    $this->assertSession()->responseContains($this->t('Saved %name configuration', ['%name' => 'Foobar']));

    // Setup widget and formatters.
    EntityFormDisplay::load('entity_test.entity_test.default')
--- a/tests/src/Functional/IntervalTest.php
+++ b/tests/src/Functional/IntervalTest.php
      'user_id[0][target_id]' => 'foo (' . $this->adminUser->id() . ')',
    ];

-    $this->submitForm($edit, t('Save'));
+    $this->submitForm($edit, $this->t('Save'));
--- a/tests/src/Functional/IntervalTest.php
+++ b/tests/src/Functional/IntervalTest.php
      // Remove one child.
      'field_foobar[2][interval]' => '',
    ];
-    $this->submitForm($edit, t('Save'));
+    $this->submitForm($edit, $this->t('Save'));
--- a/tests/src/Kernel/IntervalItemTest.php
+++ b/tests/src/Kernel/IntervalItemTest.php
   * A field storage to use in this test class.
   *
   * @var \Drupal\field\Entity\FieldStorageConfig
+   *   The configuration field storage.
--- a/tests/src/Kernel/IntervalItemTest.php
+++ b/tests/src/Kernel/IntervalItemTest.php
   * The field used in this test class.
   *
   * @var \Drupal\field\Entity\FieldConfig
+   *   The FieldConfig.
--- a/tests/src/Kernel/IntervalItemTest.php
+++ b/tests/src/Kernel/IntervalItemTest.php
  protected static $modules = ['interval'];

  /**
-   * @inheritDoc
+   * Sets the default field storage backend for fields created during tests.
+   *
+   * {@inheritdoc}
--- a/tests/src/Kernel/IntervalItemTest.php
+++ b/tests/src/Kernel/IntervalItemTest.php
   */
  public function testValueChange() {

-    // Verify entity creation.
+    // Verify the entity creation.
    $entity = EntityTest::create();
    $value = ['interval' => 30, 'period' => 'minute'];
    $entity->field_interval = $value;
    $entity->name->value = $this->randomMachineName();
    $this->entityValidateAndSave($entity);

-    // Verify initial field value
+    // Verify the initial field value.
    $this->assertEquals($entity->field_interval->interval, $value['interval']);
--- a/interval.module
+++ b/interval.module
 * Defines an interval field.
 * @copyright Copyright(c) 2011 Rowlands Group
 * @license GPL v2+ http://www.fsf.org/licensing/licenses/gpl.html
- * @author Lee Rowlands leerowlands at rowlandsgroup dot com