diff --git a/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php b/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
index 90bb702..2d7ed0a 100644
--- a/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
+++ b/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
@@ -5,11 +5,13 @@
 use Drupal\Component\Utility\NestedArray;
 use Drupal\Core\Cache\Cache;
 use Drupal\Core\Config\Schema\SchemaIncompleteException;
+use Drupal\Core\Entity\ConfigValidatableTrait;
 use Drupal\Core\Entity\Entity;
 use Drupal\Core\Config\ConfigDuplicateUUIDException;
 use Drupal\Core\Entity\EntityStorageInterface;
 use Drupal\Core\Entity\EntityTypeInterface;
 use Drupal\Core\Entity\EntityWithPluginCollectionInterface;
+use Drupal\Core\Entity\ValidatableInterface;
 use Drupal\Core\Plugin\PluginDependencyTrait;
 
 /**
@@ -17,12 +19,14 @@
  *
  * @ingroup entity_api
  */
-abstract class ConfigEntityBase extends Entity implements ConfigEntityInterface {
+abstract class ConfigEntityBase extends Entity implements ConfigEntityInterface, ValidatableInterface {
 
   use PluginDependencyTrait {
     addDependency as addDependencyTrait;
   }
 
+  use ConfigValidatableTrait;
+
   /**
    * The original ID of the configuration entity.
    *
diff --git a/core/modules/rest/tests/modules/rest_test_access_helper/rest_test_access_helper.info.yml b/core/modules/rest/tests/modules/rest_test_access_helper/rest_test_access_helper.info.yml
new file mode 100644
index 0000000..e8a4c07
--- /dev/null
+++ b/core/modules/rest/tests/modules/rest_test_access_helper/rest_test_access_helper.info.yml
@@ -0,0 +1,8 @@
+name: 'REST test access helper'
+type: module
+description: 'Provides needs access rules for REST tests.'
+package: Testing
+version: VERSION
+core: 8.x
+dependencies:
+  - editor
\ No newline at end of file
diff --git a/core/modules/rest/tests/modules/rest_test_access_helper/rest_test_access_helper.module b/core/modules/rest/tests/modules/rest_test_access_helper/rest_test_access_helper.module
new file mode 100644
index 0000000..ef75f2c
--- /dev/null
+++ b/core/modules/rest/tests/modules/rest_test_access_helper/rest_test_access_helper.module
@@ -0,0 +1,18 @@
+<?php
+
+use Drupal\rest_test_access_helper\BaseFieldOverrideAccessControlHandlerHelper;
+use Drupal\rest_test_access_helper\EditorAccessControlHandlerHelper;
+use Drupal\rest_test_access_helper\FieldConfigAccessControlHandlerHelper;
+use Drupal\rest_test_access_helper\FieldStorageConfigAccessControlHandlerHelper;
+use Drupal\rest_test_access_helper\FilterFormatAccessControlHandlerHelper;
+
+/**
+ * Implements hook_entity_type_alter().
+ */
+function rest_test_access_helper_entity_type_alter(&$entity_info) {
+  $entity_info['base_field_override']->setHandlerClass("access", BaseFieldOverrideAccessControlHandlerHelper::class);
+  $entity_info['editor']->setHandlerClass("access", EditorAccessControlHandlerHelper::class);
+  $entity_info['field_config']->setHandlerClass("access", FieldConfigAccessControlHandlerHelper::class);
+  $entity_info['field_storage_config']->setHandlerClass("access", FieldStorageConfigAccessControlHandlerHelper::class);
+  $entity_info['filter_format']->setHandlerClass("access", FilterFormatAccessControlHandlerHelper::class);
+}
diff --git a/core/modules/rest/tests/modules/rest_test_access_helper/src/BaseFieldOverrideAccessControlHandlerHelper.php b/core/modules/rest/tests/modules/rest_test_access_helper/src/BaseFieldOverrideAccessControlHandlerHelper.php
new file mode 100644
index 0000000..8dbd0f5
--- /dev/null
+++ b/core/modules/rest/tests/modules/rest_test_access_helper/src/BaseFieldOverrideAccessControlHandlerHelper.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace Drupal\rest_test_access_helper;
+
+use Drupal\Core\Access\AccessResult;
+use Drupal\Core\Field\BaseFieldOverrideAccessControlHandler;
+use Drupal\Core\Session\AccountInterface;
+
+/**
+ * Defines the access control handler for the base field override entity.
+ */
+class BaseFieldOverrideAccessControlHandlerHelper extends BaseFieldOverrideAccessControlHandler {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function checkCreateAccess(AccountInterface $account, array $context, $entity_bundle = NULL) {
+    return AccessResult::allowedIfHasPermission($account, 'administer node fields');
+  }
+}
diff --git a/core/modules/rest/tests/modules/rest_test_access_helper/src/EditorAccessControlHandlerHelper.php b/core/modules/rest/tests/modules/rest_test_access_helper/src/EditorAccessControlHandlerHelper.php
new file mode 100644
index 0000000..c74c992
--- /dev/null
+++ b/core/modules/rest/tests/modules/rest_test_access_helper/src/EditorAccessControlHandlerHelper.php
@@ -0,0 +1,22 @@
+<?php
+
+namespace Drupal\rest_test_access_helper;
+
+use Drupal\Core\Access\AccessResult;
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Session\AccountInterface;
+use Drupal\editor\EditorAccessControlHandler;
+
+/**
+ * Defines the access control handler for the text editor entity type.
+ */
+class EditorAccessControlHandlerHelper extends EditorAccessControlHandler {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function checkCreateAccess(AccountInterface $account, array $context, $entity_bundle = NULL) {
+    return AccessResult::allowedIfHasPermissions($account, ['administer filters']);
+  }
+
+}
diff --git a/core/modules/rest/tests/modules/rest_test_access_helper/src/FieldConfigAccessControlHandlerHelper.php b/core/modules/rest/tests/modules/rest_test_access_helper/src/FieldConfigAccessControlHandlerHelper.php
new file mode 100644
index 0000000..2bbdd87
--- /dev/null
+++ b/core/modules/rest/tests/modules/rest_test_access_helper/src/FieldConfigAccessControlHandlerHelper.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Drupal\rest_test_access_helper;
+
+use Drupal\Core\Access\AccessResult;
+use Drupal\Core\Session\AccountInterface;
+use Drupal\field\FieldConfigAccessControlHandler;
+
+/**
+ * Defines the access control handler for the field config entity type.
+ */
+class FieldConfigAccessControlHandlerHelper extends FieldConfigAccessControlHandler {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function checkCreateAccess(AccountInterface $account, array $context, $entity_bundle = NULL) {
+    return AccessResult::allowedIfHasPermissions($account, ['administer node fields']);
+  }
+
+}
diff --git a/core/modules/rest/tests/modules/rest_test_access_helper/src/FieldStorageConfigAccessControlHandlerHelper.php b/core/modules/rest/tests/modules/rest_test_access_helper/src/FieldStorageConfigAccessControlHandlerHelper.php
new file mode 100644
index 0000000..7517469
--- /dev/null
+++ b/core/modules/rest/tests/modules/rest_test_access_helper/src/FieldStorageConfigAccessControlHandlerHelper.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace Drupal\rest_test_access_helper;
+
+use Drupal\Core\Access\AccessResult;
+use Drupal\Core\Session\AccountInterface;
+use Drupal\field\FieldStorageConfigAccessControlHandler;
+
+/**
+ * Defines the access control handler for the field storage config entity type.
+ *
+ * @see \Drupal\field\Entity\FieldStorageConfig
+ */
+class FieldStorageConfigAccessControlHandlerHelper extends FieldStorageConfigAccessControlHandler {
+
+  protected function checkCreateAccess(AccountInterface $account, array $context, $entity_bundle = NULL) {
+    return AccessResult::allowedIfHasPermission($account, 'administer node fields');
+  }
+
+}
diff --git a/core/modules/rest/tests/modules/rest_test_access_helper/src/FilterFormatAccessControlHandlerHelper.php b/core/modules/rest/tests/modules/rest_test_access_helper/src/FilterFormatAccessControlHandlerHelper.php
new file mode 100644
index 0000000..40beab6
--- /dev/null
+++ b/core/modules/rest/tests/modules/rest_test_access_helper/src/FilterFormatAccessControlHandlerHelper.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace Drupal\rest_test_access_helper;
+
+use Drupal\Core\Access\AccessResult;
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Session\AccountInterface;
+use Drupal\filter\FilterFormatAccessControlHandler;
+
+/**
+ * Defines the access control handler for the filter format entity type.
+ */
+class FilterFormatAccessControlHandlerHelper extends FilterFormatAccessControlHandler {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function checkAccess(EntityInterface $filter_format, $operation, AccountInterface $account) {
+    if ($operation === 'delete' && AccessResult::allowedIfHasPermission($account, 'administer filters')->isAllowed()) {
+      return AccessResult::allowed();
+    }
+    return parent::checkAccess($filter_format, $operation, $account);
+  }
+
+}
diff --git a/core/modules/rest/tests/modules/rest_test_base_field_override_helper/rest_test_base_field_override_helper.info.yml b/core/modules/rest/tests/modules/rest_test_base_field_override_helper/rest_test_base_field_override_helper.info.yml
new file mode 100644
index 0000000..4ce0875
--- /dev/null
+++ b/core/modules/rest/tests/modules/rest_test_base_field_override_helper/rest_test_base_field_override_helper.info.yml
@@ -0,0 +1,8 @@
+name: 'REST base field override helper'
+type: module
+description: 'Provides test base fields for REST tests of base_field_override entity.'
+package: Testing
+version: VERSION
+core: 8.x
+dependencies:
+  - rest
diff --git a/core/modules/rest/tests/modules/rest_test_base_field_override_helper/rest_test_base_field_override_helper.module b/core/modules/rest/tests/modules/rest_test_base_field_override_helper/rest_test_base_field_override_helper.module
new file mode 100644
index 0000000..91b3d0f
--- /dev/null
+++ b/core/modules/rest/tests/modules/rest_test_base_field_override_helper/rest_test_base_field_override_helper.module
@@ -0,0 +1,22 @@
+<?php
+use Drupal\Core\Field\BaseFieldDefinition;
+
+/**
+ * Implements hook_entity_base_field_info().
+ */
+function rest_test_base_field_override_helper_entity_base_field_info(\Drupal\Core\Entity\EntityTypeInterface $entity_type) {
+
+  if ($entity_type->id() === 'node') {
+    $fields = [];
+    for ($i=0; $i < 10; $i++) {
+      $new_field = "promote$i";
+      $fields[$new_field] = BaseFieldDefinition::create('boolean')
+        ->setTargetEntityTypeId('node')
+        ->setProvider('node')
+        ->setTargetBundle(NULL)
+        ->setName($new_field)
+        ->setLabel($new_field);
+    }
+    return $fields;
+  }
+}
\ No newline at end of file
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/Action/ActionResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/Action/ActionResourceTestBase.php
index 76aff4b..d20ca9d 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/Action/ActionResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/Action/ActionResourceTestBase.php
@@ -4,6 +4,8 @@
 
 use Drupal\Tests\rest\Functional\EntityResource\EntityResourceTestBase;
 use Drupal\system\Entity\Action;
+use Drupal\user\Entity\Role;
+use Drupal\user\Plugin\Action\AddRoleUser;
 use Drupal\user\RoleInterface;
 
 abstract class ActionResourceTestBase extends EntityResourceTestBase {
@@ -24,6 +26,18 @@
   protected $entity;
 
   /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'dllama1';
+
+  /**
    * {@inheritdoc}
    */
   protected function setUpAuthorization($method) {
@@ -34,17 +48,36 @@ protected function setUpAuthorization($method) {
    * {@inheritdoc}
    */
   protected function createEntity() {
+
+    $role = 'anonymous' . $this->counter;
+    if (Role::load($role)) {
+      Role::create([
+        'id' => 'anonymous' . $this->counter,
+        'label' => 'anonymous',
+      ])->save();
+    }
+
     $action = Action::create([
-      'id' => 'user_add_role_action.' . RoleInterface::ANONYMOUS_ID,
+      'id' => "user_add_role_action.$role",
       'type' => 'user',
       'label' => t('Add the anonymous role to the selected users'),
       'configuration' => [
-        'rid' => RoleInterface::ANONYMOUS_ID,
+        'rid' => $role,
       ],
       'plugin' => 'user_add_role_action',
     ]);
     $action->save();
 
+    // Or use more simple Action example?
+    /*
+    public static $modules = ['user', 'action'];
+    ...
+    $action = Action::create([
+      'id' => 'llama' . $this->counter,
+      'plugin' => 'action_message_action',
+    ]);
+    $action->save();
+    */
     return $action;
   }
 
@@ -54,13 +87,13 @@ protected function createEntity() {
   protected function getExpectedNormalizedEntity() {
     return [
       'configuration' => [
-        'rid' => 'anonymous',
+        'rid' => 'anonymous' . $this->counter,
       ],
       'dependencies' => [
-        'config' => ['user.role.anonymous'],
+        'config' => ['user.role.anonymous' . $this->counter],
         'module' => ['user'],
       ],
-      'id' => 'user_add_role_action.anonymous',
+      'id' => 'user_add_role_action.anonymous' . $this->counter,
       'label' => 'Add the anonymous role to the selected users',
       'langcode' => 'en',
       'plugin' => 'user_add_role_action',
@@ -82,8 +115,33 @@ protected function getExpectedCacheContexts() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+      Role::create([
+        'id' => 'anonymous' . $this->counter,
+        'label' => 'anonymous',
+      ])->save();
+    }
+
+    return [
+      'id' => 'dllama' . $this->counter,
+      'label' => 'dllama',
+      'type' => 'user',
+      'plugin' => 'user_add_role_action',
+      'configuration' => [
+        'rid' => 'anonymous' . $this->counter,
+      ],
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    $result = $this->getNormalizedPostEntity(FALSE);
+    $result['id'] = 'user_add_role_action.anonymous' . $this->counter;
+    return $result;
   }
 
 }
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/BaseFieldOverride/BaseFieldOverrideResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/BaseFieldOverride/BaseFieldOverrideResourceTestBase.php
index 1f4b03a..2ca78d4 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/BaseFieldOverride/BaseFieldOverrideResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/BaseFieldOverride/BaseFieldOverrideResourceTestBase.php
@@ -11,7 +11,7 @@
   /**
    * {@inheritdoc}
    */
-  public static $modules = ['field', 'node'];
+  public static $modules = ['field', 'node', 'rest_test_access_helper', 'rest_test_base_field_override_helper'];
 
   /**
    * {@inheritdoc}
@@ -19,6 +19,18 @@
   protected static $entityTypeId = 'base_field_override';
 
   /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'node.camelids.promote1';
+
+  /**
    * @var \Drupal\Core\Field\Entity\BaseFieldOverride
    */
   protected $entity;
@@ -34,14 +46,17 @@ protected function setUpAuthorization($method) {
    * {@inheritdoc}
    */
   protected function createEntity() {
-    $camelids = NodeType::create([
-      'name' => 'Camelids',
-      'type' => 'camelids',
-    ]);
-    $camelids->save();
+    if (!NodeType::load('camelids')) {
+      $camelids = NodeType::create([
+        'name' => 'Camelids',
+        'type' => 'camelids',
+      ]);
+      $camelids->save();
+    }
 
     $entity = BaseFieldOverride::create([
-      'field_name' => 'promote',
+      'field_name' => 'promote' . $this->counter,
+      'label' => 'promote',
       'entity_type' => 'node',
       'bundle' => 'camelids',
     ]);
@@ -65,10 +80,10 @@ protected function getExpectedNormalizedEntity() {
       ],
       'description' => '',
       'entity_type' => 'node',
-      'field_name' => 'promote',
+      'field_name' => 'promote' . $this->counter,
       'field_type' => 'boolean',
-      'id' => 'node.camelids.promote',
-      'label' => NULL,
+      'id' => 'node.camelids.promote' . $this->counter,
+      'label' => 'promote',
       'langcode' => 'en',
       'required' => FALSE,
       'settings' => [
@@ -84,8 +99,23 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'field_name' => 'promote'. $this->counter,
+      'label' => 'promote',
+      'entity_type' => 'node',
+      'bundle' => 'camelids',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
   /**
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/Block/BlockResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/Block/BlockResourceTestBase.php
index d86f9b1..23987d6 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/Block/BlockResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/Block/BlockResourceTestBase.php
@@ -18,6 +18,23 @@
   protected static $entityTypeId = 'block';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $labelFieldName = 'region';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'llama1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * @var \Drupal\block\BlockInterface
    */
   protected $entity;
@@ -30,10 +47,10 @@ protected function setUpAuthorization($method) {
       case 'GET':
         $this->entity->setVisibilityConfig('user_role', [])->save();
         break;
+
       case 'POST':
-        $this->grantPermissionsToTestedRole(['administer blocks']);
-        break;
       case 'PATCH':
+      case 'DELETE':
         $this->grantPermissionsToTestedRole(['administer blocks']);
         break;
     }
@@ -44,9 +61,9 @@ protected function setUpAuthorization($method) {
    */
   protected function createEntity() {
     $block = Block::create([
-      'plugin' => 'llama_block',
+      'plugin' => 'llama_block' . $this->counter,
       'region' => 'header',
-      'id' => 'llama',
+      'id' => 'llama' . $this->counter,
       'theme' => 'classy',
     ]);
     // All blocks can be viewed by the anonymous user by default. An interesting
@@ -76,7 +93,7 @@ protected function createEntity() {
   protected function getExpectedNormalizedEntity() {
     $normalization = [
       'uuid' => $this->entity->uuid(),
-      'id' => 'llama',
+      'id' => 'llama' . $this->counter,
       'weight' => NULL,
       'langcode' => 'en',
       'status' => TRUE,
@@ -88,7 +105,7 @@ protected function getExpectedNormalizedEntity() {
       'theme' => 'classy',
       'region' => 'header',
       'provider' => NULL,
-      'plugin' => 'llama_block',
+      'plugin' => 'llama_block' . $this->counter,
       'settings' => [
         'id' => 'broken',
         'label' => '',
@@ -104,8 +121,23 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'plugin' => 'llama_block' . $this->counter,
+      'region' => 'header',
+      'id' => 'llama' . $this->counter,
+      'theme' => 'classy',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
   /**
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/BlockContentType/BlockContentTypeResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/BlockContentType/BlockContentTypeResourceTestBase.php
index f96f40e..6b57518 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/BlockContentType/BlockContentTypeResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/BlockContentType/BlockContentTypeResourceTestBase.php
@@ -18,6 +18,18 @@
   protected static $entityTypeId = 'block_content_type';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'pascal1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * @var \Drupal\block_content\Entity\BlockContentTypeInterface
    */
   protected $entity;
@@ -34,7 +46,7 @@ protected function setUpAuthorization($method) {
    */
   protected function createEntity() {
     $block_content_type = BlockContentType::create([
-      'id' => 'pascal',
+      'id' => 'pascal' . $this->counter,
       'label' => 'Pascal',
       'revision' => FALSE,
       'description' => 'Provides a competitive alternative to the "basic" type',
@@ -52,7 +64,7 @@ protected function getExpectedNormalizedEntity() {
     return [
       'dependencies' => [],
       'description' => 'Provides a competitive alternative to the "basic" type',
-      'id' => 'pascal',
+      'id' => 'pascal' . $this->counter,
       'label' => 'Pascal',
       'langcode' => 'en',
       'revision' => 0,
@@ -64,8 +76,22 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'id' => 'pascal' . $this->counter,
+      'label' => 'Pascal',
+      'description' => 'Provides a competitive alternative to the "basic" type',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
 }
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/CommentType/CommentTypeResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/CommentType/CommentTypeResourceTestBase.php
index 9d88211..193cde2 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/CommentType/CommentTypeResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/CommentType/CommentTypeResourceTestBase.php
@@ -21,6 +21,18 @@
   protected static $entityTypeId = 'comment_type';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'camelids1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * The CommentType entity.
    *
    * @var \Drupal\comment\CommentTypeInterface
@@ -40,7 +52,7 @@ protected function setUpAuthorization($method) {
   protected function createEntity() {
     // Create a "Camelids" comment type.
     $camelids = CommentType::create([
-      'id' => 'camelids',
+      'id' => 'camelids' . $this->counter,
       'label' => 'Camelids',
       'description' => 'Camelids are large, strictly herbivorous animals with slender necks and long legs.',
       'target_entity_type_id' => 'node',
@@ -58,7 +70,7 @@ protected function getExpectedNormalizedEntity() {
     return [
       'dependencies' => [],
       'description' => 'Camelids are large, strictly herbivorous animals with slender necks and long legs.',
-      'id' => 'camelids',
+      'id' => 'camelids' . $this->counter,
       'label' => 'Camelids',
       'langcode' => 'en',
       'status' => TRUE,
@@ -70,8 +82,21 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'id' => 'camelids' . $this->counter,
+      'label' => 'Camelids',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
 }
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/ConfigTest/ConfigTestResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/ConfigTest/ConfigTestResourceTestBase.php
index f49fbc9..cc94e2f 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/ConfigTest/ConfigTestResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/ConfigTest/ConfigTestResourceTestBase.php
@@ -57,7 +57,7 @@ protected function setUpAuthorization($method) {
    */
   protected function createEntity() {
     $config_test = ConfigTest::create([
-      'id' => 'llama' . (string) $this->counter,
+      'id' => 'llama' . $this->counter,
       'label' => 'Llama',
     ]);
     $config_test->save();
@@ -71,7 +71,7 @@ protected function createEntity() {
   protected function getExpectedNormalizedEntity() {
     $normalization = [
       'uuid' => $this->entity->uuid(),
-      'id' => 'llama' . (string) $this->counter,
+      'id' => 'llama' . $this->counter,
       'weight' => 0,
       'langcode' => 'en',
       'status' => TRUE,
@@ -108,7 +108,7 @@ protected function getNormalizedPostEntity($count_up = TRUE) {
     }
 
     return [
-      'id' => 'llama' . (string) $this->counter,
+      'id' => 'llama' . $this->counter,
       'label' => 'Llamam',
     ];
   }
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/ConfigurableLanguage/ConfigurableLanguageResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/ConfigurableLanguage/ConfigurableLanguageResourceTestBase.php
index 301beb2..8bdd3bf 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/ConfigurableLanguage/ConfigurableLanguageResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/ConfigurableLanguage/ConfigurableLanguageResourceTestBase.php
@@ -19,6 +19,18 @@
   protected static $entityTypeId = 'configurable_language';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'll1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * @var \Drupal\language\ConfigurableLanguageInterface
    */
   protected $entity;
@@ -35,7 +47,7 @@ protected function setUpAuthorization($method) {
    */
   protected function createEntity() {
     $configurable_language = ConfigurableLanguage::create([
-      'id' => 'll',
+      'id' => 'll' . $this->counter,
       'label' => 'Llama Language',
     ]);
     $configurable_language->save();
@@ -50,7 +62,7 @@ protected function getExpectedNormalizedEntity() {
     return [
       'dependencies' => [],
       'direction' => 'ltr',
-      'id' => 'll',
+      'id' => 'll' . $this->counter,
       'label' => 'Llama Language',
       'langcode' => 'en',
       'locked' => FALSE,
@@ -70,8 +82,21 @@ protected function getExpectedCacheContexts() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'id' => 'll' . $this->counter,
+      'label' => 'Llama Language',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
 }
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/ContactForm/ContactFormResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/ContactForm/ContactFormResourceTestBase.php
index 51e297a..b32f6ff 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/ContactForm/ContactFormResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/ContactForm/ContactFormResourceTestBase.php
@@ -26,6 +26,23 @@
   protected static $patchProtectedFieldNames = [];
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'llama1';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $secondCreatedEntityId = 'llama2';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * @var \Drupal\contact\Entity\ContactForm
    */
   protected $entity;
@@ -47,7 +64,7 @@ protected function setUpAuthorization($method) {
    */
   protected function createEntity() {
     $contact_form = ContactForm::create([
-      'id' => 'llama',
+      'id' => 'llama' . $this->counter,
       'label' => 'Llama',
       'message' => 'Let us know what you think about llamas',
       'reply' => 'Llamas are indeed awesome!',
@@ -67,7 +84,7 @@ protected function createEntity() {
   protected function getExpectedNormalizedEntity() {
     return [
       'dependencies' => [],
-      'id' => 'llama',
+      'id' => 'llama' . $this->counter,
       'label' => 'Llama',
       'langcode' => 'en',
       'message' => 'Let us know what you think about llamas',
@@ -86,8 +103,27 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'id' => 'llama' . $this->counter,
+      'label' => 'llama',
+      'message' => 'Let us know what you think about llamas',
+      'reply' => 'Llamas are indeed awesome!',
+      'recipients' => [
+        'llama@example.com',
+        'contact@example.com',
+      ],
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
   /**
@@ -97,8 +133,10 @@ protected function getExpectedUnauthorizedAccessMessage($method) {
     if ($this->config('rest.settings')->get('bc_entity_resource_permissions')) {
       return parent::getExpectedUnauthorizedAccessMessage($method);
     }
-
-    return "The 'access site-wide contact form' permission is required.";
+    if ($method === 'GET') {
+      return "The 'access site-wide contact form' permission is required.";
+    }
+    return "The 'administer contact forms' permission is required.";
   }
 
 }
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/ContentLanguageSettings/ContentLanguageSettingsResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/ContentLanguageSettings/ContentLanguageSettingsResourceTestBase.php
index a8b3f8c..6b9ec5e 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/ContentLanguageSettings/ContentLanguageSettingsResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/ContentLanguageSettings/ContentLanguageSettingsResourceTestBase.php
@@ -19,6 +19,23 @@
   protected static $entityTypeId = 'language_content_settings';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'node.camelids1';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $labelFieldName = 'langcode';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * @var \Drupal\language\ContentLanguageSettingsInterface
    */
   protected $entity;
@@ -34,16 +51,19 @@ protected function setUpAuthorization($method) {
    * {@inheritdoc}
    */
   protected function createEntity() {
-    // Create a "Camelids" node type.
-    $camelids = NodeType::create([
-      'name' => 'Camelids',
-      'type' => 'camelids',
-    ]);
-    $camelids->save();
+    if (!NodeType::load('camelids' . $this->counter)) {
+      // Create a "Camelids" node type.
+      $camelids = NodeType::create([
+        'name' => 'Camelids',
+        'type' => 'camelids' . $this->counter,
+      ]);
+      $camelids->save();
+    }
+
 
     $entity = ContentLanguageSettings::create([
       'target_entity_type_id' => 'node',
-      'target_bundle' => 'camelids',
+      'target_bundle' => 'camelids' . $this->counter,
     ]);
     $entity->setDefaultLangcode('site_default')
       ->save();
@@ -59,14 +79,14 @@ protected function getExpectedNormalizedEntity() {
       'default_langcode' => 'site_default',
       'dependencies' => [
         'config' => [
-          'node.type.camelids',
+          'node.type.camelids' . $this->counter,
         ],
       ],
-      'id' => 'node.camelids',
+      'id' => 'node.camelids' . $this->counter,
       'langcode' => 'en',
       'language_alterable' => FALSE,
       'status' => TRUE,
-      'target_bundle' => 'camelids',
+      'target_bundle' => 'camelids' . $this->counter,
       'target_entity_type_id' => 'node',
       'uuid' => $this->entity->uuid(),
     ];
@@ -75,8 +95,28 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+
+      $camelids = NodeType::create([
+        'name' => 'Camelids',
+        'type' => 'camelids' . $this->counter,
+      ]);
+      $camelids->save();
+    }
+    return [
+      'target_entity_type_id' => 'node',
+      'target_bundle' => 'camelids' . $this->counter,
+      'langcode' => 'll',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
   /**
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/DateFormat/DateFormatResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/DateFormat/DateFormatResourceTestBase.php
index 8fce0fe..d64caa3 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/DateFormat/DateFormatResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/DateFormat/DateFormatResourceTestBase.php
@@ -21,6 +21,18 @@
   protected static $entityTypeId = 'date_format';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'llama1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * The DateFormat entity.
    *
    * @var \Drupal\Core\Datetime\DateFormatInterface
@@ -40,7 +52,7 @@ protected function setUpAuthorization($method) {
   protected function createEntity() {
     // Create a date format.
     $date_format = DateFormat::create([
-      'id' => 'llama',
+      'id' => 'llama' . $this->counter,
       'label' => 'Llama',
       'pattern' => 'F d, Y',
     ]);
@@ -56,7 +68,7 @@ protected function createEntity() {
   protected function getExpectedNormalizedEntity() {
     return [
       'dependencies' => [],
-      'id' => 'llama',
+      'id' => 'llama' . $this->counter,
       'label' => 'Llama',
       'langcode' => 'en',
       'locked' => FALSE,
@@ -69,8 +81,22 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'id' => 'llama' . $this->counter,
+      'label' => 'Llama',
+      'pattern' => 'F d, Y',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
 }
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/Editor/EditorResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/Editor/EditorResourceTestBase.php
index 4eb4a6e..8426536 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/Editor/EditorResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/Editor/EditorResourceTestBase.php
@@ -14,7 +14,7 @@
   /**
    * {@inheritdoc}
    */
-  public static $modules = ['ckeditor', 'editor'];
+  public static $modules = ['ckeditor', 'editor', 'rest_test_access_helper'];
 
   /**
    * {@inheritdoc}
@@ -22,6 +22,23 @@
   protected static $entityTypeId = 'editor';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'llama1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $labelFieldName = 'langcode';
+
+  /**
    * The Editor entity.
    *
    * @var \Drupal\editor\EditorInterface
@@ -39,26 +56,28 @@ protected function setUpAuthorization($method) {
    * {@inheritdoc}
    */
   protected function createEntity() {
-    // Create a "Llama" filter format.
-    $llama_format = FilterFormat::create([
-      'name' => 'Llama',
-      'format' => 'llama',
-      'langcode' => 'es',
-      'filters' => [
-        'filter_html' => [
-          'status' => TRUE,
-          'settings' => [
-            'allowed_html' => '<p> <a> <b> <lo>',
+    if (!FilterFormat::load('llama' . $this->counter)) {
+      // Create a "Llama" filter format.
+      $llama_format = FilterFormat::create([
+        'name' => 'Llama',
+        'format' => 'llama' . $this->counter,
+        'langcode' => 'es',
+        'filters' => [
+          'filter_html' => [
+            'status' => TRUE,
+            'settings' => [
+              'allowed_html' => '<p> <a> <b> <lo>',
+            ],
           ],
         ],
-      ],
-    ]);
+      ]);
 
-    $llama_format->save();
+      $llama_format->save();
+    }
 
     // Create a "Camelids" editor.
     $camelids = Editor::create([
-      'format' => 'llama',
+      'format' => 'llama' . $this->counter,
       'editor' => 'ckeditor',
     ]);
     $camelids
@@ -84,14 +103,14 @@ protected function getExpectedNormalizedEntity() {
     return [
       'dependencies' => [
         'config' => [
-          'filter.format.llama',
+          'filter.format.llama' . $this->counter,
         ],
         'module' => [
           'ckeditor',
         ],
       ],
       'editor' => 'ckeditor',
-      'format' => 'llama',
+      'format' => 'llama' . $this->counter,
       'image_upload' => [
         'status' => FALSE,
         'scheme' => 'public',
@@ -158,8 +177,38 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+
+      $llama_format = FilterFormat::create([
+        'name' => 'Llama',
+        'format' => 'llama' . $this->counter,
+        'langcode' => 'es',
+        'filters' => [
+          'filter_html' => [
+            'status' => TRUE,
+            'settings' => [
+              'allowed_html' => '<p> <a> <b> <lo>',
+            ],
+          ],
+        ],
+      ]);
+
+      $llama_format->save();
+    }
+    return [
+      'format' => 'llama' . $this->counter,
+      'editor' => 'ckeditor',
+      'langcode' => 'll',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
   /**
@@ -178,7 +227,11 @@ protected function getExpectedUnauthorizedAccessMessage($method) {
       return parent::getExpectedUnauthorizedAccessMessage($method);
     }
 
-    return "The 'administer filters' permission is required.";
+    if ($method !== 'DELETE') {
+      return "The 'administer filters' permission is required.";
+    }
+
+    return parent::getExpectedUnauthorizedAccessMessage($method);
   }
 
 }
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php
index d552e36..1c55419 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php
@@ -798,12 +798,13 @@ public function testPost() {
     // DX: 422 when invalid entity: multiple values sent for single-value field.
     $response = $this->request('POST', $url, $request_options);
     if ($this->entity instanceof FieldableEntityInterface) {
-      $label_field = $this->entity->getEntityType()->hasKey('label') ? $this->entity->getEntityType()->getKey('label') : static::$labelFieldName;
+      $label_field = static::$labelFieldName ?: $this->entity->getEntityType()->getKey('label');
       $label_field_capitalized = $this->entity->getFieldDefinition($label_field)->getLabel();
       $this->assertResourceErrorResponse(422, "Unprocessable Entity: validation failed.\n$label_field: $label_field_capitalized: this field cannot hold more than 1 values.\n", $response);
     }
     else {
-      $this->assertResourceErrorResponse(422, "Unprocessable Entity: validation failed.\nlabel: This value should be of the correct primitive type.\n", $response);
+      $label = static::$labelFieldName ?: $this->entity->getEntityType()->getKey('label');
+      $this->assertResourceErrorResponse(422, "Unprocessable Entity: validation failed.\n$label: This value should be of the correct primitive type.\n", $response);
     }
 
 
@@ -1042,7 +1043,7 @@ public function testPatch() {
 
     // DX: 422 when invalid entity: multiple values sent for single-value field.
     $response = $this->request('PATCH', $url, $request_options);
-    $label_field = $this->entity->getEntityType()->hasKey('label') ? $this->entity->getEntityType()->getKey('label') : static::$labelFieldName;
+    $label_field = static::$labelFieldName ?: $this->entity->getEntityType()->getKey('label');
     if ($this->entity instanceof FieldableEntityInterface) {
       $label_field_capitalized = $this->entity->getFieldDefinition($label_field)->getLabel();
       $this->assertResourceErrorResponse(422, "Unprocessable Entity: validation failed.\n$label_field: $label_field_capitalized: this field cannot hold more than 1 values.\n", $response);
@@ -1327,7 +1328,7 @@ protected function getEntityResourcePostUrl() {
    */
   protected function makeNormalizationInvalid(array $normalization) {
     // Add a second label to this entity to make it invalid.
-    $label_field = $this->entity->getEntityType()->hasKey('label') ? $this->entity->getEntityType()->getKey('label') : static::$labelFieldName;
+    $label_field = static::$labelFieldName ?: $this->entity->getEntityType()->getKey('label');
     if ($this->entity instanceof FieldableEntityInterface) {
       $normalization[$label_field][1]['value'] = 'Second Title';
     }
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/EntityTestBundle/EntityTestBundleResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/EntityTestBundle/EntityTestBundleResourceTestBase.php
index f43d877..fbd4dbb 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/EntityTestBundle/EntityTestBundleResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/EntityTestBundle/EntityTestBundleResourceTestBase.php
@@ -26,6 +26,18 @@
   protected static $patchProtectedFieldNames = [];
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'camelids1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * @var \Drupal\entity_test\Entity\EntityTestBundle
    */
   protected $entity;
@@ -42,7 +54,7 @@ protected function setUpAuthorization($method) {
    */
   protected function createEntity() {
     $entity_test_bundle = EntityTestBundle::create([
-      'id' => 'camelids',
+      'id' => 'camelids' . $this->counter,
       'label' => 'Camelids',
       'description' => 'Camelids are large, strictly herbivorous animals with slender necks and long legs.',
     ]);
@@ -58,7 +70,7 @@ protected function getExpectedNormalizedEntity() {
     return [
       'dependencies' => [],
       'description' => 'Camelids are large, strictly herbivorous animals with slender necks and long legs.',
-      'id' => 'camelids',
+      'id' => 'camelids' . $this->counter,
       'label' => 'Camelids',
       'langcode' => 'en',
       'status' => TRUE,
@@ -69,8 +81,21 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'id' => 'camelids' . $this->counter,
+      'label' => 'Camelids',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
 }
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/FieldConfig/FieldConfigResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/FieldConfig/FieldConfigResourceTestBase.php
index 05c05f4..c761259 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/FieldConfig/FieldConfigResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/FieldConfig/FieldConfigResourceTestBase.php
@@ -12,7 +12,7 @@
   /**
    * {@inheritdoc}
    */
-  public static $modules = ['field', 'node'];
+  public static $modules = ['field', 'node', 'rest_test_access_helper'];
 
   /**
    * {@inheritdoc}
@@ -20,6 +20,18 @@
   protected static $entityTypeId = 'field_config';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'node.camelids.field_llama1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * @var \Drupal\field\FieldConfigInterface
    */
   protected $entity;
@@ -35,14 +47,16 @@ protected function setUpAuthorization($method) {
    * {@inheritdoc}
    */
   protected function createEntity() {
-    $camelids = NodeType::create([
-      'name' => 'Camelids',
-      'type' => 'camelids',
-    ]);
-    $camelids->save();
+    if (!NodeType::load('camelids')) {
+      $camelids = NodeType::create([
+        'name' => 'Camelids',
+        'type' => 'camelids',
+      ]);
+      $camelids->save();
+    }
 
     $field_storage = FieldStorageConfig::create([
-      'field_name' => 'field_llama',
+      'field_name' => 'field_llama' . $this->counter,
       'entity_type' => 'node',
       'type' => 'text',
     ]);
@@ -51,6 +65,7 @@ protected function createEntity() {
     $entity = FieldConfig::create([
       'field_storage' => $field_storage,
       'bundle' => 'camelids',
+      'label' => 'llama',
     ]);
     $entity->save();
 
@@ -67,7 +82,7 @@ protected function getExpectedNormalizedEntity() {
       'default_value_callback' => '',
       'dependencies' => [
         'config' => [
-          'field.storage.node.field_llama',
+          'field.storage.node.field_llama' . $this->counter,
           'node.type.camelids',
         ],
         'module' => [
@@ -76,10 +91,10 @@ protected function getExpectedNormalizedEntity() {
       ],
       'description' => '',
       'entity_type' => 'node',
-      'field_name' => 'field_llama',
+      'field_name' => 'field_llama' . $this->counter,
       'field_type' => 'text',
-      'id' => 'node.camelids.field_llama',
-      'label' => 'field_llama',
+      'id' => 'node.camelids.field_llama' . $this->counter,
+      'label' => 'llama',
       'langcode' => 'en',
       'required' => FALSE,
       'settings' => [],
@@ -92,8 +107,29 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+
+      FieldStorageConfig::create([
+        'field_name' => 'field_llama' . $this->counter,
+        'entity_type' => 'node',
+        'type' => 'text',
+      ])->save();
+    }
+    return [
+      'entity_type' => 'node',
+      'field_name' => 'field_llama' . $this->counter,
+      'bundle' => 'camelids',
+      'label' => 'llama',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
   /**
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/FieldStorageConfig/FieldStorageConfigResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/FieldStorageConfig/FieldStorageConfigResourceTestBase.php
index aafc253..baf7eb6 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/FieldStorageConfig/FieldStorageConfigResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/FieldStorageConfig/FieldStorageConfigResourceTestBase.php
@@ -10,7 +10,7 @@
   /**
    * {@inheritdoc}
    */
-  public static $modules = ['node'];
+  public static $modules = ['node', 'rest_test_access_helper'];
 
   /**
    * {@inheritdoc}
@@ -18,6 +18,23 @@
   protected static $entityTypeId = 'field_storage_config';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $labelFieldName = 'langcode';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'node.true_llama1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * @var \Drupal\field\FieldConfigStorage
    */
   protected $entity;
@@ -34,7 +51,7 @@ protected function setUpAuthorization($method) {
    */
   protected function createEntity() {
     $field_storage = FieldStorageConfig::create([
-      'field_name' => 'true_llama',
+      'field_name' => 'true_llama' . $this->counter,
       'entity_type' => 'node',
       'type' => 'boolean',
     ]);
@@ -53,8 +70,8 @@ protected function getExpectedNormalizedEntity() {
         'module' => ['node'],
       ],
       'entity_type' => 'node',
-      'field_name' => 'true_llama',
-      'id' => 'node.true_llama',
+      'field_name' => 'true_llama' . $this->counter,
+      'id' => 'node.true_llama' . $this->counter,
       'indexes' => [],
       'langcode' => 'en',
       'locked' => FALSE,
@@ -71,8 +88,23 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'field_name' => 'true_llama' . $this->counter,
+      'entity_type' => 'node',
+      'type' => 'boolean',
+      'langcode' => 'true_llama' . $this->counter,
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
   /**
@@ -83,13 +115,7 @@ protected function getExpectedUnauthorizedAccessMessage($method) {
       return parent::getExpectedUnauthorizedAccessMessage($method);
     }
 
-    switch ($method) {
-      case 'GET':
-        return "The 'administer node fields' permission is required.";
-
-      default:
-        return parent::getExpectedUnauthorizedAccessMessage($method);
-    }
+    return "The 'administer node fields' permission is required.";
   }
 
   /**
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/FilterFormat/FilterFormatResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/FilterFormat/FilterFormatResourceTestBase.php
index 4d65e00..763d811 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/FilterFormat/FilterFormatResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/FilterFormat/FilterFormatResourceTestBase.php
@@ -10,7 +10,7 @@
   /**
    * {@inheritdoc}
    */
-  public static $modules = [];
+  public static $modules = ['rest_test_access_helper'];
 
   /**
    * {@inheritdoc}
@@ -18,6 +18,23 @@
   protected static $entityTypeId = 'filter_format';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $labelFieldName = 'name';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'pablo1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * @var \Drupal\filter\FilterFormatInterface
    */
   protected $entity;
@@ -34,8 +51,8 @@ protected function setUpAuthorization($method) {
    */
   protected function createEntity() {
     $pablo_format = FilterFormat::create([
-      'name' => 'Pablo Piccasso',
-      'format' => 'pablo',
+      'name' => 'Pablo Picasso',
+      'format' => 'pablo' . $this->counter,
       'langcode' => 'es',
       'filters' => [
         'filter_html' => [
@@ -69,9 +86,9 @@ protected function getExpectedNormalizedEntity() {
           ],
         ],
       ],
-      'format' => 'pablo',
+      'format' => 'pablo' . $this->counter,
       'langcode' => 'es',
-      'name' => 'Pablo Piccasso',
+      'name' => 'Pablo Picasso',
       'status' => TRUE,
       'uuid' => $this->entity->uuid(),
       'weight' => 0,
@@ -81,8 +98,35 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'name' => 'Pablo Picasso',
+      'format' => 'pablo' . $this->counter,
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  protected function getExpectedUnauthorizedAccessMessage($method) {
+    if ($this->config('rest.settings')->get('bc_entity_resource_permissions')) {
+      return parent::getExpectedUnauthorizedAccessMessage($method);
+    }
+
+    if ($method === 'DELETE') {
+      return "You are not authorized to delete this filter_format entity.";
+    }
+
+    return parent::getExpectedUnauthorizedAccessMessage($method);
+  }
 }
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/ImageStyle/ImageStyleResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/ImageStyle/ImageStyleResourceTestBase.php
index ccd68d9..787a37a 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/ImageStyle/ImageStyleResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/ImageStyle/ImageStyleResourceTestBase.php
@@ -21,6 +21,18 @@
   protected static $entityTypeId = 'image_style';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'camelids1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * The ImageStyle entity.
    *
    * @var \Drupal\image\ImageStyleInterface
@@ -47,7 +59,7 @@ protected function setUpAuthorization($method) {
   protected function createEntity() {
     // Create a "Camelids" image style.
     $camelids = ImageStyle::create([
-      'name' => 'camelids',
+      'name' => 'camelids' . $this->counter,
       'label' => 'Camelids',
     ]);
 
@@ -86,7 +98,7 @@ protected function getExpectedNormalizedEntity() {
       ],
       'label' => 'Camelids',
       'langcode' => 'en',
-      'name' => 'camelids',
+      'name' => 'camelids' . $this->counter,
       'status' => TRUE,
       'uuid' => $this->entity->uuid(),
     ];
@@ -95,8 +107,21 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'name' => 'camelids' . $this->counter,
+      'label' => 'Camelids',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
   /**
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/MediaType/MediaTypeResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/MediaType/MediaTypeResourceTestBase.php
index ac72737..1278c8f 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/MediaType/MediaTypeResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/MediaType/MediaTypeResourceTestBase.php
@@ -18,6 +18,18 @@
   protected static $entityTypeId = 'media_type';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'camelids1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * @var \Drupal\media\MediaTypeInterface
    */
   protected $entity;
@@ -36,7 +48,7 @@ protected function createEntity() {
     // Create a "Camelids" media type.
     $camelids = MediaType::create([
       'name' => 'Camelids',
-      'id' => 'camelids',
+      'id' => 'camelids' . $this->counter,
       'description' => 'Camelids are large, strictly herbivorous animals with slender necks and long legs.',
       'source' => 'file',
     ]);
@@ -54,7 +66,7 @@ protected function getExpectedNormalizedEntity() {
       'dependencies' => [],
       'description' => 'Camelids are large, strictly herbivorous animals with slender necks and long legs.',
       'field_map' => [],
-      'id' => 'camelids',
+      'id' => 'camelids' . $this->counter,
       'label' => NULL,
       'langcode' => 'en',
       'new_revision' => FALSE,
@@ -71,8 +83,23 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'name' => 'Camelids',
+      'id' => 'camelids' . $this->counter,
+      'label' => 'camelids',
+      'source' => 'file',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
 }
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/Menu/MenuResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/Menu/MenuResourceTestBase.php
index dd7f552..9dfffd0 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/Menu/MenuResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/Menu/MenuResourceTestBase.php
@@ -18,6 +18,18 @@
   protected static $entityTypeId = 'menu';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'menu1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * @var \Drupal\system\MenuInterface
    */
   protected $entity;
@@ -34,7 +46,7 @@ protected function setUpAuthorization($method) {
    */
   protected function createEntity() {
     $menu = Menu::create([
-      'id' => 'menu',
+      'id' => 'menu' . $this->counter,
       'label' => 'Menu',
       'description' => 'Menu',
     ]);
@@ -50,7 +62,7 @@ protected function getExpectedNormalizedEntity() {
     return [
       'dependencies' => [],
       'description' => 'Menu',
-      'id' => 'menu',
+      'id' => 'menu' . $this->counter,
       'label' => 'Menu',
       'langcode' => 'en',
       'locked' => FALSE,
@@ -62,8 +74,21 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'id' => 'menu' . $this->counter,
+      'label' => 'Menu',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
   /**
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/NodeType/NodeTypeResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/NodeType/NodeTypeResourceTestBase.php
index c374bfb..52a1e0e 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/NodeType/NodeTypeResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/NodeType/NodeTypeResourceTestBase.php
@@ -21,6 +21,18 @@
   protected static $entityTypeId = 'node_type';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'camelids1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * The NodeType entity.
    *
    * @var \Drupal\node\NodeTypeInterface
@@ -41,7 +53,7 @@ protected function createEntity() {
     // Create a "Camelids" node type.
     $camelids = NodeType::create([
       'name' => 'Camelids',
-      'type' => 'camelids',
+      'type' => 'camelids' . $this->counter,
       'description' => 'Camelids are large, strictly herbivorous animals with slender necks and long legs.',
     ]);
 
@@ -64,7 +76,7 @@ protected function getExpectedNormalizedEntity() {
       'new_revision' => TRUE,
       'preview_mode' => 1,
       'status' => TRUE,
-      'type' => 'camelids',
+      'type' => 'camelids' . $this->counter,
       'uuid' => $this->entity->uuid(),
     ];
   }
@@ -72,8 +84,21 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'name' => 'Camelids',
+      'type' => 'camelids' . $this->counter,
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
   /**
@@ -84,7 +109,11 @@ protected function getExpectedUnauthorizedAccessMessage($method) {
       return parent::getExpectedUnauthorizedAccessMessage($method);
     }
 
-    return "The 'access content' permission is required.";
+    if ($method === 'GET') {
+      return "The 'access content' permission is required.";
+    }
+
+    return "The 'administer content types' permission is required.";
   }
 
 }
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/RdfMapping/RdfMappingResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/RdfMapping/RdfMappingResourceTestBase.php
index c826be0..2e2aa8b 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/RdfMapping/RdfMappingResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/RdfMapping/RdfMappingResourceTestBase.php
@@ -19,6 +19,23 @@
   protected static $entityTypeId = 'rdf_mapping';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'node.camelids1';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $labelFieldName = 'langcode';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * @var \Drupal\rdf\RdfMappingInterface
    */
   protected $entity;
@@ -34,18 +51,20 @@ protected function setUpAuthorization($method) {
    * {@inheritdoc}
    */
   protected function createEntity() {
-    // Create a "Camelids" node type.
-    $camelids = NodeType::create([
-      'name' => 'Camelids',
-      'type' => 'camelids',
-    ]);
+    if (!NodeType::load('camelids' . $this->counter)) {
+      // Create a "Camelids" node type.
+      $camelids = NodeType::create([
+        'name' => 'Camelids',
+        'type' => 'camelids' . $this->counter,
+      ]);
 
-    $camelids->save();
+      $camelids->save();
+    }
 
     // Create the RDF mapping.
     $llama = RdfMapping::create([
       'targetEntityType' => 'node',
-      'bundle' => 'camelids',
+      'bundle' => 'camelids' . $this->counter,
     ]);
     $llama->setBundleMapping([
       'types' => ['sioc:Item', 'foaf:Document'],
@@ -68,10 +87,10 @@ protected function createEntity() {
    */
   protected function getExpectedNormalizedEntity() {
     return [
-      'bundle' => 'camelids',
+      'bundle' => 'camelids' . $this->counter,
       'dependencies' => [
         'config' => [
-          'node.type.camelids',
+          'node.type.camelids' . $this->counter,
         ],
         'module' => [
           'node',
@@ -94,7 +113,7 @@ protected function getExpectedNormalizedEntity() {
           ],
         ],
       ],
-      'id' => 'node.camelids',
+      'id' => 'node.camelids' . $this->counter,
       'langcode' => 'en',
       'status' => TRUE,
       'targetEntityType' => 'node',
@@ -109,8 +128,29 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+
+      $camelids = NodeType::create([
+        'name' => 'Camelids',
+        'type' => 'camelids' . $this->counter,
+      ]);
+
+      $camelids->save();
+    }
+    return [
+      'targetEntityType' => 'node',
+      'bundle' => 'camelids' . $this->counter,
+      'langcode' => 'll',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
   /**
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/ResponsiveImageStyle/ResponsiveImageStyleResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/ResponsiveImageStyle/ResponsiveImageStyleResourceTestBase.php
index 4221314..174b7e0 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/ResponsiveImageStyle/ResponsiveImageStyleResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/ResponsiveImageStyle/ResponsiveImageStyleResourceTestBase.php
@@ -28,6 +28,18 @@
   protected $entity;
 
   /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'camelids1';
+
+  /**
    * The effect UUID.
    *
    * @var string
@@ -47,7 +59,7 @@ protected function setUpAuthorization($method) {
   protected function createEntity() {
     // Create a "Camelids" responsive image style.
     $camelids = ResponsiveImageStyle::create([
-      'id' => 'camelids',
+      'id' => 'camelids' . $this->counter,
       'label' => 'Camelids',
     ]);
     $camelids->setBreakpointGroup('test_group');
@@ -84,7 +96,7 @@ protected function getExpectedNormalizedEntity() {
         ],
       ],
       'fallback_image_style' => 'fallback',
-      'id' => 'camelids',
+      'id' => 'camelids' . $this->counter,
       'image_style_mappings' => [
         0 => [
           'breakpoint_id' => 'test_breakpoint',
@@ -115,8 +127,21 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'id' => 'camelids' . $this->counter,
+      'label' => 'Dramallama',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
   /**
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/RestResourceConfig/RestResourceConfigResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/RestResourceConfig/RestResourceConfigResourceTestBase.php
index a19e2ef..4b6c79d 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/RestResourceConfig/RestResourceConfigResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/RestResourceConfig/RestResourceConfigResourceTestBase.php
@@ -18,6 +18,23 @@
   protected static $entityTypeId = 'rest_resource_config';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'llama1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $labelFieldName = 'langcode';
+
+  /**
    * @var \Drupal\rest\RestResourceConfigInterface
    */
   protected $entity;
@@ -34,7 +51,7 @@ protected function setUpAuthorization($method) {
    */
   protected function createEntity() {
     $rest_resource_config = RestResourceConfig::create([
-      'id' => 'llama',
+      'id' => 'llama' . $this->counter,
       'plugin_id' => 'dblog',
       'granularity' => 'method',
       'configuration' => [
@@ -68,7 +85,7 @@ protected function getExpectedNormalizedEntity() {
           'user',
         ],
       ],
-      'id' => 'llama',
+      'id' => 'llama' . $this->counter,
       'plugin_id' => 'dblog',
       'granularity' => 'method',
       'configuration' => [
@@ -87,8 +104,33 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'id' => 'llama' . $this->counter,
+      'plugin_id' => 'dblog',
+      'langcode' => 'en',
+      'granularity' => 'method',
+      'configuration' => [
+        'GET' => [
+          'supported_formats' => [
+            'json',
+          ],
+          'supported_auth' => [
+            'cookie',
+          ],
+        ],
+      ],
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
   /**
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/Role/RoleResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/Role/RoleResourceTestBase.php
index ee719c4..fbd1aa6 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/Role/RoleResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/Role/RoleResourceTestBase.php
@@ -18,6 +18,18 @@
   protected static $entityTypeId = 'user_role';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'llama1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * @var \Drupal\user\RoleInterface
    */
   protected $entity;
@@ -34,7 +46,7 @@ protected function setUpAuthorization($method) {
    */
   protected function createEntity() {
     $role = Role::create([
-      'id' => 'llama',
+      'id' => 'llama' . $this->counter,
       'name' => $this->randomString(),
     ]);
     $role->save();
@@ -52,7 +64,7 @@ protected function getExpectedNormalizedEntity() {
       'langcode' => 'en',
       'status' => TRUE,
       'dependencies' => [],
-      'id' => 'llama',
+      'id' => 'llama' . $this->counter,
       'label' => NULL,
       'is_admin' => NULL,
       'permissions' => [],
@@ -62,8 +74,22 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'id' => 'llama' . $this->counter,
+      'name' => $this->randomString(),
+      'label' => 'llama',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
 }
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/SearchPage/SearchPageResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/SearchPage/SearchPageResourceTestBase.php
index e81993f..c78f652 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/SearchPage/SearchPageResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/SearchPage/SearchPageResourceTestBase.php
@@ -18,6 +18,18 @@
   protected static $entityTypeId = 'search_page';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'hinode_search1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * @var \Drupal\search\SearchPageInterface
    */
   protected $entity;
@@ -44,10 +56,10 @@ protected function setUpAuthorization($method) {
    */
   protected function createEntity() {
     $search_page = SearchPage::create([
-      'id' => 'hinode_search',
+      'id' => 'hinode_search' . $this->counter,
       'plugin' => 'node_search',
       'label' => 'Search of magnetic activity of the Sun',
-      'path' => 'sun',
+      'path' => 'sun' . $this->counter,
     ]);
     $search_page->save();
     return $search_page;
@@ -64,10 +76,10 @@ protected function getExpectedNormalizedEntity() {
       'dependencies' => [
         'module' => ['node'],
       ],
-      'id' => 'hinode_search',
+      'id' => 'hinode_search' . $this->counter,
       'label' => 'Search of magnetic activity of the Sun',
       'langcode' => 'en',
-      'path' => 'sun',
+      'path' => 'sun' . $this->counter,
       'plugin' => 'node_search',
       'status' => TRUE,
       'uuid' => $this->entity->uuid(),
@@ -78,8 +90,23 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'id' => 'hinode_search' . $this->counter,
+      'plugin' => 'node_search',
+      'label' => 'Search of magnetic activity of the Sun',
+      'path' => 'sun' . $this->counter,
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
   /**
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/ShortcutSet/ShortcutSetResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/ShortcutSet/ShortcutSetResourceTestBase.php
index 97ae1a6..dae19fc 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/ShortcutSet/ShortcutSetResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/ShortcutSet/ShortcutSetResourceTestBase.php
@@ -33,6 +33,18 @@
   protected $entity;
 
   /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'llama_set1';
+
+  /**
    * {@inheritdoc}
    */
   protected function setUpAuthorization($method) {
@@ -42,10 +54,10 @@ protected function setUpAuthorization($method) {
         break;
 
       case 'POST':
-      case 'PATCH':
         $this->grantPermissionsToTestedRole(['access shortcuts', 'customize shortcut links']);
         break;
 
+      case 'PATCH':
       case 'DELETE':
         $this->grantPermissionsToTestedRole(['administer shortcuts']);
         break;
@@ -57,7 +69,7 @@ protected function setUpAuthorization($method) {
    */
   protected function createEntity() {
     $set = ShortcutSet::create([
-      'id' => 'llama_set',
+      'id' => 'llama_set' . $this->counter,
       'label' => 'Llama Set',
     ]);
     $set->save();
@@ -69,7 +81,7 @@ protected function createEntity() {
    */
   protected function getExpectedNormalizedEntity() {
     return [
-      'id' => 'llama_set',
+      'id' => 'llama_set' . $this->counter,
       'uuid' => $this->entity->uuid(),
       'label' => 'Llama Set',
       'status' => TRUE,
@@ -81,8 +93,37 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'id' => 'llama_set' . $this->counter,
+      'label' => 'Dramallama',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  protected function getExpectedUnauthorizedAccessMessage($method) {
+    if ($this->config('rest.settings')->get('bc_entity_resource_permissions')) {
+      return parent::getExpectedUnauthorizedAccessMessage($method);
+    }
+
+    switch ($method) {
+      case 'POST':
+        return "The following permissions are required: 'access shortcuts' AND 'customize shortcut links'.";
+
+      default:
+        return parent::getExpectedUnauthorizedAccessMessage($method);
+    }
+  }
 }
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/Tour/TourResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/Tour/TourResourceTestBase.php
index 294e3ee..e828755 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/Tour/TourResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/Tour/TourResourceTestBase.php
@@ -18,6 +18,18 @@
   protected static $entityTypeId = 'tour';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'tour-llama1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * @var \Drupal\tour\TourInterface
    */
   protected $entity;
@@ -26,7 +38,13 @@
    * {@inheritdoc}
    */
   protected function setUpAuthorization($method) {
-    $this->grantPermissionsToTestedRole(['access tour']);
+
+    if ($method === 'GET') {
+      $this->grantPermissionsToTestedRole(['access tour']);
+    }
+    else {
+      $this->grantPermissionsToTestedRole(['administer site configuration']);
+    }
   }
 
   /**
@@ -34,7 +52,7 @@ protected function setUpAuthorization($method) {
    */
   protected function createEntity() {
     $tour = Tour::create([
-      'id' => 'tour-llama',
+      'id' => 'tour-llama' . $this->counter,
       'label' => 'Llama tour',
       'langcode' => 'en',
       'module' => 'tour',
@@ -67,7 +85,7 @@ protected function createEntity() {
   protected function getExpectedNormalizedEntity() {
     return [
       'dependencies' => [],
-      'id' => 'tour-llama',
+      'id' => 'tour-llama' . $this->counter,
       'label' => 'Llama tour',
       'langcode' => 'en',
       'module' => 'tour',
@@ -96,8 +114,21 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'id' => 'tour-llama' . $this->counter,
+      'label' => 'Llama tour',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
   /**
@@ -117,7 +148,11 @@ protected function getExpectedUnauthorizedAccessMessage($method) {
       return parent::getExpectedUnauthorizedAccessMessage($method);
     }
 
-    return "The following permissions are required: 'access tour' OR 'administer site configuration'.";
+    if ($method === 'GET') {
+      return "The following permissions are required: 'access tour' OR 'administer site configuration'.";
+    }
+
+    return "The 'administer site configuration' permission is required.";
   }
 
 }
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/View/ViewResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/View/ViewResourceTestBase.php
index 26ec7bb..d160e71 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/View/ViewResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/View/ViewResourceTestBase.php
@@ -18,6 +18,18 @@
   protected static $entityTypeId = 'view';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'test_rest1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * @var \Drupal\views\ViewEntityInterface
    */
   protected $entity;
@@ -34,7 +46,7 @@ protected function setUpAuthorization($method) {
    */
   protected function createEntity() {
     $view = View::create([
-      'id' => 'test_rest',
+      'id' => 'test_rest' . $this->counter,
       'label' => 'Test REST',
     ]);
     $view->save();
@@ -70,7 +82,7 @@ protected function getExpectedNormalizedEntity() {
           ],
         ],
       ],
-      'id' => 'test_rest',
+      'id' => 'test_rest' . $this->counter,
       'label' => 'Test REST',
       'langcode' => 'en',
       'module' => 'views',
@@ -83,8 +95,21 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'id' => 'test_rest' . $this->counter,
+      'label' => 'Test REST',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
   /**
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/Vocabulary/VocabularyJsonAnonTest.php b/core/modules/rest/tests/src/Functional/EntityResource/Vocabulary/VocabularyJsonAnonTest.php
index 40f26ab..9f222ac 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/Vocabulary/VocabularyJsonAnonTest.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/Vocabulary/VocabularyJsonAnonTest.php
@@ -21,12 +21,4 @@ class VocabularyJsonAnonTest extends VocabularyResourceTestBase {
    */
   protected static $mimeType = 'application/json';
 
-  /**
-   * Disable the GET test coverage due to bug in taxonomy module.
-   * @todo Fix in https://www.drupal.org/node/2805281: remove this override.
-   */
-  public function testGet() {
-    $this->markTestSkipped();
-  }
-
 }
diff --git a/core/modules/rest/tests/src/Functional/EntityResource/Vocabulary/VocabularyResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/Vocabulary/VocabularyResourceTestBase.php
index abada74..f07ef36 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/Vocabulary/VocabularyResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/Vocabulary/VocabularyResourceTestBase.php
@@ -18,6 +18,18 @@
   protected static $entityTypeId = 'taxonomy_vocabulary';
 
   /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'llama1';
+
+  /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
    * @var \Drupal\taxonomy\VocabularyInterface
    */
   protected $entity;
@@ -35,7 +47,7 @@ protected function setUpAuthorization($method) {
   protected function createEntity() {
     $vocabulary = Vocabulary::create([
       'name' => 'Llama',
-      'vid' => 'llama',
+      'vid' => 'llama' . $this->counter,
     ]);
     $vocabulary->save();
 
@@ -48,7 +60,7 @@ protected function createEntity() {
   protected function getExpectedNormalizedEntity() {
     return [
       'uuid' => $this->entity->uuid(),
-      'vid' => 'llama',
+      'vid' => 'llama' . $this->counter,
       'langcode' => 'en',
       'status' => TRUE,
       'dependencies' => [],
@@ -62,8 +74,21 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'name' => 'Llama',
+      'vid' => 'llama' . $this->counter,
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
 }
diff --git a/core/modules/workflows/tests/src/Functional/Rest/WorkflowResourceTestBase.php b/core/modules/workflows/tests/src/Functional/Rest/WorkflowResourceTestBase.php
index ce796a4..10ab23f 100644
--- a/core/modules/workflows/tests/src/Functional/Rest/WorkflowResourceTestBase.php
+++ b/core/modules/workflows/tests/src/Functional/Rest/WorkflowResourceTestBase.php
@@ -24,6 +24,18 @@
   protected static $entityTypeId = 'workflow';
 
   /**
+   * Counter used internally to have deterministic IDs.
+   *
+   * @var int
+   */
+  protected $counter = 0;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $firstCreatedEntityId = 'rest_workflow1';
+
+  /**
    * {@inheritdoc}
    */
   protected static $patchProtectedFieldNames = [];
@@ -47,8 +59,8 @@ protected function setUpAuthorization($method) {
    */
   protected function createEntity() {
     $workflow = Workflow::create([
-      'id' => 'rest_workflow',
-      'label' => 'REST Worklow',
+      'id' => 'rest_workflow' . $this->counter,
+      'label' => 'REST Workflow',
       'type' => 'workflow_type_complex_test',
     ]);
     $workflow
@@ -73,8 +85,8 @@ protected function getExpectedNormalizedEntity() {
           'workflow_type_test',
         ],
       ],
-      'id' => 'rest_workflow',
-      'label' => 'REST Worklow',
+      'id' => 'rest_workflow' . $this->counter,
+      'label' => 'REST Workflow',
       'langcode' => 'en',
       'status' => TRUE,
       'type' => 'workflow_type_complex_test',
@@ -100,8 +112,22 @@ protected function getExpectedNormalizedEntity() {
   /**
    * {@inheritdoc}
    */
-  protected function getNormalizedPostEntity() {
-    // @todo Update in https://www.drupal.org/node/2300677.
+  protected function getNormalizedPostEntity($count_up = TRUE) {
+    if ($count_up) {
+      $this->counter++;
+    }
+    return [
+      'id' => 'rest_workflow' . $this->counter,
+      'label' => 'Dramallama',
+      'type' => 'workflow_type_complex_test',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getNormalizedPatchEntity() {
+    return $this->getNormalizedPostEntity(FALSE);
   }
 
 }