.../Tests/CustomBlockCacheTagsTest.php             |    4 ++--
 .../Drupal/comment/Tests/CommentCacheTagsTest.php  |    4 ++--
 .../lib/Drupal/node/Tests/NodeCacheTagsTest.php    |    6 ++---
 .../Tests/Entity/EntityCacheTagsTestBase.php       |   23 ++++----------------
 .../Entity/EntityWithUriCacheTagsTestBase.php      |    4 ++--
 .../Drupal/taxonomy/Tests/TermCacheTagsTest.php    |    4 ++--
 .../lib/Drupal/user/Tests/UserCacheTagsTest.php    |    4 ++--
 7 files changed, 17 insertions(+), 32 deletions(-)

diff --git a/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockCacheTagsTest.php b/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockCacheTagsTest.php
index 6270631..ccd51dd 100644
--- a/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockCacheTagsTest.php
+++ b/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockCacheTagsTest.php
@@ -23,13 +23,13 @@ class CustomBlockCacheTagsTest extends EntityCacheTagsTestBase {
    * {@inheritdoc}
    */
   public static function getInfo() {
-    return static::generateStandardizedInfo('Custom Block', 'Custom Block');
+    return parent::generateStandardizedInfo('Custom Block', 'Custom Block');
   }
 
   /**
    * {@inheritdoc}
    */
-  protected static function createEntity() {
+  protected function createEntity() {
     // Create a "Llama" custom block.
     $custom_block = entity_create('custom_block', array(
       'info' => 'Llama',
diff --git a/core/modules/comment/lib/Drupal/comment/Tests/CommentCacheTagsTest.php b/core/modules/comment/lib/Drupal/comment/Tests/CommentCacheTagsTest.php
index d42ec20..07cac6e 100644
--- a/core/modules/comment/lib/Drupal/comment/Tests/CommentCacheTagsTest.php
+++ b/core/modules/comment/lib/Drupal/comment/Tests/CommentCacheTagsTest.php
@@ -23,7 +23,7 @@ class CommentCacheTagsTest extends EntityWithUriCacheTagsTestBase {
    * {@inheritdoc}
    */
   public static function getInfo() {
-    return static::generateStandardizedInfo('Comment', 'Comment');
+    return parent::generateStandardizedInfo('Comment', 'Comment');
   }
 
   /**
@@ -42,7 +42,7 @@ public function setUp() {
   /**
    * {@inheritdoc}
    */
-  protected static function createEntity() {
+  protected function createEntity() {
     // Create a "bar" bundle for the "entity_test" entity type and create.
     $bundle = 'bar';
     entity_test_create_bundle($bundle, NULL, 'entity_test');
diff --git a/core/modules/node/lib/Drupal/node/Tests/NodeCacheTagsTest.php b/core/modules/node/lib/Drupal/node/Tests/NodeCacheTagsTest.php
index 514c2d9..0d3dc2a 100644
--- a/core/modules/node/lib/Drupal/node/Tests/NodeCacheTagsTest.php
+++ b/core/modules/node/lib/Drupal/node/Tests/NodeCacheTagsTest.php
@@ -24,7 +24,7 @@ class NodeCacheTagsTest extends EntityWithUriCacheTagsTestBase {
    * {@inheritdoc}
    */
   public static function getInfo() {
-    return static::generateStandardizedInfo('Node', 'Node');
+    return parent::generateStandardizedInfo('Node', 'Node');
   }
 
   /**
@@ -43,7 +43,7 @@ public function setUp() {
   /**
    * {@inheritdoc}
    */
-  protected static function createEntity() {
+  protected function createEntity() {
     // Create a "Camelids" node type.
     entity_create('node_type', array(
       'name' => 'Camelids',
@@ -62,7 +62,7 @@ protected static function createEntity() {
   /**
    * {@inheritdoc}
    */
-  protected static function getAdditionalCacheTagsForEntity(EntityInterface $node) {
+  protected function getAdditionalCacheTagsForEntity(EntityInterface $node) {
     return array('user:' . $node->getOwnerId());
   }
 
diff --git a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityCacheTagsTestBase.php b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityCacheTagsTestBase.php
index d426390..f1a0c84 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityCacheTagsTestBase.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityCacheTagsTestBase.php
@@ -58,7 +58,7 @@ public function setUp() {
     $user_role->save();
 
     // Create an entity.
-    $this->entity = static::createEntity();
+    $this->entity = $this->createEntity();
 
     // If this is a fieldable entity, then add a configurable field. We will use
     // this configurable field in later tests to ensure that modifications to
@@ -93,7 +93,7 @@ public function setUp() {
     list(
       $this->referencing_entity,
       $this->non_referencing_entity,
-    ) = static::createReferenceTestEntities($this->entity);
+    ) = $this->createReferenceTestEntities($this->entity);
   }
 
   /**
@@ -119,36 +119,21 @@ protected static function generateStandardizedInfo($entity_type_label, $group) {
   /**
    * Creates the entity to be tested.
    *
-   * This is a static method to guarantee that subclasses that implement it
-   * don't set additional properties on the object: it ensures a clear, strict
-   * contract.
-   *
    * @return \Drupal\Core\Entity\EntityInterface
    *   The entity to be tested.
    */
-  protected static function createEntity() {
-    // PHP doesn't allow us to declare this method as abstract protected static,
-    // so we simply throw an exception here if this has not been implemented by
-    // a child class.
-    throw new \RuntimeException(String::format('@class must implement \Drupal\system\Tests\Entity\EntityCacheTagsTestBase::createEntity().', array(
-      '@class' => get_called_class(),
-    )));
-  }
+  abstract protected function createEntity();
 
   /**
    * Creates a referencing and a non-referencing entity for testing purposes.
    *
-   * This is a static method to guarantee that subclasses that override it
-   * don't set additional properties on the object: it ensures a clear, strict
-   * contract.
-   *
    * @param \Drupal\Core\Entity\EntityInterface $referenced_entity
    *  The entity that the referencing entity should reference.
    *
    * @return \Drupal\Core\Entity\EntityInterface[]
    *  An array containing a referencing entity and a non-referencing entity.
    */
-  protected static function createReferenceTestEntities($referenced_entity) {
+  protected function createReferenceTestEntities($referenced_entity) {
     // All referencing entities should be of the type 'entity_test'.
     $entity_type = 'entity_test';
 
diff --git a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityWithUriCacheTagsTestBase.php b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityWithUriCacheTagsTestBase.php
index a979174..de46515 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityWithUriCacheTagsTestBase.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityWithUriCacheTagsTestBase.php
@@ -26,7 +26,7 @@
    *
    * @see \Drupal\system\Tests\Entity\EntityCacheTagsTestBase::createEntity()
    */
-  protected static function getAdditionalCacheTagsForEntity(EntityInterface $entity) {
+  protected function getAdditionalCacheTagsForEntity(EntityInterface $entity) {
     return array();
   }
 
@@ -58,7 +58,7 @@ public function testEntityUri() {
     if (\Drupal::entityManager()->getDefinition($entity_type)->isRenderCacheable()) {
       $cid = 'entity_view:' . $entity_type . ':' . $this->entity->id() . ':full:stark:r.anonymous';
       $cache_entry = \Drupal::cache()->get($cid);
-      $expected_cache_tags = array_merge(array($view_cache_tag, $cache_tag), static::getAdditionalCacheTagsForEntity($this->entity));
+      $expected_cache_tags = array_merge(array($view_cache_tag, $cache_tag), $this->getAdditionalCacheTagsForEntity($this->entity));
       $this->assertIdentical($cache_entry->tags, $expected_cache_tags);
     }
 
diff --git a/core/modules/taxonomy/lib/Drupal/taxonomy/Tests/TermCacheTagsTest.php b/core/modules/taxonomy/lib/Drupal/taxonomy/Tests/TermCacheTagsTest.php
index 6d7b649..6cd6457 100644
--- a/core/modules/taxonomy/lib/Drupal/taxonomy/Tests/TermCacheTagsTest.php
+++ b/core/modules/taxonomy/lib/Drupal/taxonomy/Tests/TermCacheTagsTest.php
@@ -23,13 +23,13 @@ class TermCacheTagsTest extends EntityWithUriCacheTagsTestBase {
    * {@inheritdoc}
    */
   public static function getInfo() {
-    return static::generateStandardizedInfo('Taxonomy term', 'Taxonomy');
+    return parent::generateStandardizedInfo('Taxonomy term', 'Taxonomy');
   }
 
   /**
    * {@inheritdoc}
    */
-  protected static function createEntity() {
+  protected function createEntity() {
     // Create a "Camelids" vocabulary.
     $vocabulary = entity_create('taxonomy_vocabulary',  array(
       'name' => 'Camelids',
diff --git a/core/modules/user/lib/Drupal/user/Tests/UserCacheTagsTest.php b/core/modules/user/lib/Drupal/user/Tests/UserCacheTagsTest.php
index 8db5b7b..a80be50 100644
--- a/core/modules/user/lib/Drupal/user/Tests/UserCacheTagsTest.php
+++ b/core/modules/user/lib/Drupal/user/Tests/UserCacheTagsTest.php
@@ -23,7 +23,7 @@ class UserCacheTagsTest extends EntityWithUriCacheTagsTestBase {
    * {@inheritdoc}
    */
   public static function getInfo() {
-    return static::generateStandardizedInfo('User', 'User');
+    return parent::generateStandardizedInfo('User', 'User');
   }
 
   /**
@@ -42,7 +42,7 @@ public function setUp() {
   /**
    * {@inheritdoc}
    */
-  protected static function createEntity() {
+  protected function createEntity() {
     // Create a "Llama" user.
     $user = entity_create('user', array(
       'name' => 'Llama',