diff --git a/tests/src/Functional/MetaEntityCacheTagsTest.php b/tests/src/Functional/MetaEntityCacheTagsTest.php
index 8d879fd..7fe91c4 100644
--- a/tests/src/Functional/MetaEntityCacheTagsTest.php
+++ b/tests/src/Functional/MetaEntityCacheTagsTest.php
@@ -48,7 +48,7 @@ class MetaEntityCacheTagsTest extends EntityWithUriCacheTagsTestBase {
    */
   public function createEntity() {
     MetaEntityType::load('visit_count')->set('mapping', [
-      'entity_test' => ['entity_test' => NULL],
+      'entity_test' => ['entity_test' => []],
     ])->save();
 
     $target_entity = EntityTest::create([
diff --git a/tests/src/Kernel/AutoCreationTest.php b/tests/src/Kernel/AutoCreationTest.php
index a70d62a..7a5fe91 100644
--- a/tests/src/Kernel/AutoCreationTest.php
+++ b/tests/src/Kernel/AutoCreationTest.php
@@ -13,7 +13,7 @@ use Drupal\meta_entity\Entity\MetaEntityType;
  *
  * @group meta_entity
  */
-class AutoCreationDelectionTest extends KernelTestBase {
+class AutoCreationTest extends KernelTestBase {
 
   /**
    * {@inheritdoc}
@@ -41,7 +41,7 @@ class AutoCreationDelectionTest extends KernelTestBase {
     // Set the mapping for but don't set any 'auto-*' flag.
     $meta_entity_type->set('mapping', [
       'entity_test' => [
-        'entity_test' => NULL,
+        'entity_test' => [],
       ],
     ])->save();
 
diff --git a/tests/src/Kernel/MappedTargetEntityConstraintTest.php b/tests/src/Kernel/MappedTargetEntityConstraintTest.php
index 5e55abc..f90dd4f 100644
--- a/tests/src/Kernel/MappedTargetEntityConstraintTest.php
+++ b/tests/src/Kernel/MappedTargetEntityConstraintTest.php
@@ -80,7 +80,7 @@ class MappedTargetEntityConstraintTest extends KernelTestBase {
     // the different bundle "visit_count". It should still throw a validation
     // error.
     MetaEntityType::load('download_count')->set('mapping', [
-      'entity_test' => ['entity_test' => NULL],
+      'entity_test' => ['entity_test' => []],
     ])->save();
 
     $violations = $meta_entity->validate();
@@ -91,7 +91,7 @@ class MappedTargetEntityConstraintTest extends KernelTestBase {
     // meta entity type. This provides the correct mapping, and the constraint
     // violation should be gone.
     MetaEntityType::load('visit_count')->set('mapping', [
-      'entity_test' => ['entity_test' => NULL],
+      'entity_test' => ['entity_test' => []],
     ])->save();
 
     $violations = $meta_entity->validate();
diff --git a/tests/src/Kernel/MetaEntityRepositoryTest.php b/tests/src/Kernel/MetaEntityRepositoryTest.php
index 383cb1e..3b115d3 100644
--- a/tests/src/Kernel/MetaEntityRepositoryTest.php
+++ b/tests/src/Kernel/MetaEntityRepositoryTest.php
@@ -43,13 +43,13 @@ class MetaEntityRepositoryTest extends KernelTestBase {
     $this->container->get('entity_type.bundle.info')->clearCachedBundles();
 
     MetaEntityType::load('visit_count')->set('mapping', [
-      'entity_test' => ['foo' => NULL],
-      'node' => ['page' => NULL],
-      'user' => ['user' => NULL],
+      'entity_test' => ['foo' => []],
+      'node' => ['page' => []],
+      'user' => ['user' => []],
     ])->save();
     MetaEntityType::load('download_count')->set('mapping', [
-      'entity_test' => ['bar' => NULL],
-      'node' => ['article' => NULL],
+      'entity_test' => ['bar' => []],
+      'node' => ['article' => []],
     ])->save();
     $service = $this->container->get('meta_entity.repository');
 
diff --git a/tests/src/Kernel/UniquePerMetaTypeAndTargetConstraintTest.php b/tests/src/Kernel/UniquePerMetaTypeAndTargetConstraintTest.php
index 9bf877d..35ac9d9 100644
--- a/tests/src/Kernel/UniquePerMetaTypeAndTargetConstraintTest.php
+++ b/tests/src/Kernel/UniquePerMetaTypeAndTargetConstraintTest.php
@@ -39,10 +39,10 @@ class UniquePerMetaTypeAndTargetConstraintTest extends KernelTestBase {
     $this->installEntitySchema('meta_entity');
     $this->installConfig(['meta_entity_test']);
     MetaEntityType::load('visit_count')->set('mapping', [
-      'entity_test' => ['entity_test' => NULL],
+      'entity_test' => ['entity_test' => []],
     ])->save();
     MetaEntityType::load('download_count')->set('mapping', [
-      'entity_test' => ['entity_test' => NULL],
+      'entity_test' => ['entity_test' => []],
     ])->save();
   }