diff --git a/.gitignore b/.gitignore
index b9e60d3..50dd546 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,5 @@ composer.lock
 reports
 vendor
 drush
+
+.phpunit.result.cache
diff --git a/tests/Drupal/Tests/Driver/Drupal7FieldHandlerTest.php b/tests/Drupal/Tests/Driver/Drupal7FieldHandlerTest.php
index da91982..7878567 100644
--- a/tests/Drupal/Tests/Driver/Drupal7FieldHandlerTest.php
+++ b/tests/Drupal/Tests/Driver/Drupal7FieldHandlerTest.php
@@ -2,6 +2,8 @@
 
 namespace Drupal\Tests\Driver;
 
+use DMS\PHPUnitExtensions\ArraySubset\Assert;
+
 /**
  * Tests the Drupal 7 field handlers.
  */
@@ -32,7 +34,7 @@ public function testFieldHandlers($class_name, $entity, $entity_type, array $fie
 
     $field_name = $field['field_name'];
     $expanded_values = $handler->expand($this->values($entity->$field_name));
-    $this->assertArraySubset($expected_values, $expanded_values);
+    Assert::assertArraySubset($expected_values, $expanded_values);
   }
 
   /**
diff --git a/tests/Drupal/Tests/Driver/FieldHandlerAbstractTest.php b/tests/Drupal/Tests/Driver/FieldHandlerAbstractTest.php
index 11fd57b..165e6f7 100644
--- a/tests/Drupal/Tests/Driver/FieldHandlerAbstractTest.php
+++ b/tests/Drupal/Tests/Driver/FieldHandlerAbstractTest.php
@@ -12,7 +12,7 @@ abstract class FieldHandlerAbstractTest extends TestCase {
   /**
    * {@inheritdoc}
    */
-  public function tearDown() {
+  public function tearDown(): void {
     \Mockery::close();
   }