diff --git a/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php b/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
index 2d2beb5..8a278ae 100644
--- a/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
+++ b/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
@@ -290,7 +290,7 @@ public function toArray() {
         $properties[$export_name] = $this->get($property_name);
       }
     }
-    if (empty($this->thirdPartySettings)) {
+    if (empty($this->third_party_settings)) {
       unset($properties['third_party_settings']);
     }
     return $properties;
diff --git a/core/lib/Drupal/Core/Config/Entity/ConfigEntityType.php b/core/lib/Drupal/Core/Config/Entity/ConfigEntityType.php
index 71bc435..5ba9f53 100644
--- a/core/lib/Drupal/Core/Config/Entity/ConfigEntityType.php
+++ b/core/lib/Drupal/Core/Config/Entity/ConfigEntityType.php
@@ -15,7 +15,7 @@
 /**
  * Provides an implementation of a configuration entity type and its metadata.
  */
-class ConfigEntityType extends EntityType {
+class ConfigEntityType extends EntityType implements ConfigEntityTypeInterface {
 
   /**
    * Length limit of the configuration entity prefix.
@@ -189,11 +189,7 @@ protected function checkStorageClass($class) {
   }
 
   /**
-   * Gets the config entity properties to export if declared on the annotation.
-   *
-   * @return array|bool
-   *   The properties to export or FALSE if they can not be determine from the
-   *   config entity type annotation.
+   * {@inheritdoc}
    */
   public function getPropertiesToExport() {
     if (!empty($this->config_export)) {
diff --git a/core/lib/Drupal/Core/Config/Entity/ConfigEntityTypeInterface.php b/core/lib/Drupal/Core/Config/Entity/ConfigEntityTypeInterface.php
new file mode 100644
index 0000000..d0aaecf
--- /dev/null
+++ b/core/lib/Drupal/Core/Config/Entity/ConfigEntityTypeInterface.php
@@ -0,0 +1,26 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Entity\EntityTypeInterface.
+ */
+
+namespace Drupal\Core\Config\Entity;
+
+use Drupal\Core\Entity\EntityTypeInterface;
+
+/**
+ * Provides an interface for an configuration entity type and its metadata.
+ */
+interface ConfigEntityTypeInterface extends EntityTypeInterface {
+
+  /**
+   * Gets the config entity properties to export if declared on the annotation.
+   *
+   * @return array|bool
+   *   The properties to export or FALSE if they can not be determine from the
+   *   config entity type annotation.
+   */
+  public function getPropertiesToExport();
+
+}
diff --git a/core/modules/config/src/Tests/ConfigSchemaTest.php b/core/modules/config/src/Tests/ConfigSchemaTest.php
index 8a8f649..11865ef 100644
--- a/core/modules/config/src/Tests/ConfigSchemaTest.php
+++ b/core/modules/config/src/Tests/ConfigSchemaTest.php
@@ -209,6 +209,7 @@ function testSchemaMapping() {
 
     $this->assertEqual($definition, $expected, 'Retrieved the right metadata for the first effect of image.style.medium');
 
+    $a = \Drupal::config('config_test.dynamic.third_party');
     $test = \Drupal::service('config.typed')->get('config_test.dynamic.third_party')->get('third_party_settings.config_schema_test');
     $definition = $test->getDataDefinition()->toArray();
     $expected = array();
diff --git a/core/modules/field/tests/src/Unit/FieldConfigEntityUnitTest.php b/core/modules/field/tests/src/Unit/FieldConfigEntityUnitTest.php
index 6904110..2bce97d 100644
--- a/core/modules/field/tests/src/Unit/FieldConfigEntityUnitTest.php
+++ b/core/modules/field/tests/src/Unit/FieldConfigEntityUnitTest.php
@@ -22,7 +22,7 @@ class FieldConfigEntityUnitTest extends UnitTestCase {
   /**
    * The entity type used for testing.
    *
-   * @var \Drupal\Core\Entity\EntityTypeInterface|\PHPUnit_Framework_MockObject_MockObject
+   * @var \Drupal\Core\Config\Entity\ConfigEntityTypeInterface|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $entityType;
 
@@ -73,7 +73,7 @@ class FieldConfigEntityUnitTest extends UnitTestCase {
    */
   protected function setUp() {
     $this->entityTypeId = $this->randomMachineName();
-    $this->entityType = $this->getMock('\Drupal\Core\Entity\EntityTypeInterface');
+    $this->entityType = $this->getMock('\Drupal\Core\Config\Entity\ConfigEntityTypeInterface');
 
     $this->entityManager = $this->getMock('\Drupal\Core\Entity\EntityManagerInterface');
 
diff --git a/core/modules/field/tests/src/Unit/FieldStorageConfigEntityUnitTest.php b/core/modules/field/tests/src/Unit/FieldStorageConfigEntityUnitTest.php
index cd05b9b..424424a 100644
--- a/core/modules/field/tests/src/Unit/FieldStorageConfigEntityUnitTest.php
+++ b/core/modules/field/tests/src/Unit/FieldStorageConfigEntityUnitTest.php
@@ -19,13 +19,6 @@
 class FieldStorageConfigEntityUnitTest extends UnitTestCase {
 
   /**
-   * The entity type used for testing.
-   *
-   * @var \Drupal\Core\Entity\EntityTypeInterface|\PHPUnit_Framework_MockObject_MockObject
-   */
-  protected $entityType;
-
-  /**
    * The entity manager used for testing.
    *
    * @var \Drupal\Core\Entity\EntityManagerInterface|\PHPUnit_Framework_MockObject_MockObject
@@ -64,7 +57,7 @@ protected function setUp() {
    */
   public function testCalculateDependencies() {
     // Create a mock entity type for FieldStorageConfig.
-    $fieldStorageConfigentityType = $this->getMock('\Drupal\Core\Entity\EntityTypeInterface');
+    $fieldStorageConfigentityType = $this->getMock('\Drupal\Core\Config\Entity\ConfigEntityTypeInterface');
     $fieldStorageConfigentityType->expects($this->any())
       ->method('getProvider')
       ->will($this->returnValue('field'));
diff --git a/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityBaseUnitTest.php b/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityBaseUnitTest.php
index 9456d33..fe1e1a1 100644
--- a/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityBaseUnitTest.php
+++ b/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityBaseUnitTest.php
@@ -30,7 +30,7 @@ class ConfigEntityBaseUnitTest extends UnitTestCase {
   /**
    * The entity type used for testing.
    *
-   * @var \Drupal\Core\Entity\EntityTypeInterface|\PHPUnit_Framework_MockObject_MockObject
+   * @var \Drupal\Core\Config\Entity\ConfigEntityTypeInterface|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $entityType;
 
@@ -102,7 +102,7 @@ protected function setUp() {
     );
     $this->entityTypeId = $this->randomMachineName();
     $this->provider = $this->randomMachineName();
-    $this->entityType = $this->getMock('\Drupal\Core\Entity\EntityTypeInterface');
+    $this->entityType = $this->getMock('\Drupal\Core\Config\Entity\ConfigEntityTypeInterface');
     $this->entityType->expects($this->any())
       ->method('getProvider')
       ->will($this->returnValue($this->provider));
@@ -456,9 +456,26 @@ public function testSort() {
    * @covers ::toArray
    */
   public function testToArray() {
+    $this->typedConfigManager->expects($this->never())
+      ->method('getDefinition');
+    $this->entityType->expects($this->any())
+      ->method('getPropertiesToExport')
+      ->willReturn(['id' => 'configId', 'dependencies' => 'dependencies']);
+    $properties = $this->entity->toArray();
+    $this->assertInternalType('array', $properties);
+    $this->assertEquals(array('configId' => $this->entity->id(), 'dependencies' => array()), $properties);
+  }
+
+  /**
+   * @covers ::toArray
+   */
+  public function testToArraySchemaFallback() {
     $this->typedConfigManager->expects($this->once())
       ->method('getDefinition')
       ->will($this->returnValue(array('mapping' => array('id' => '', 'dependencies' => ''))));
+    $this->entityType->expects($this->any())
+      ->method('getPropertiesToExport')
+      ->willReturn([]);
     $properties = $this->entity->toArray();
     $this->assertInternalType('array', $properties);
     $this->assertEquals(array('id' => $this->entity->id(), 'dependencies' => array()), $properties);
@@ -470,6 +487,9 @@ public function testToArray() {
    * @expectedException \Drupal\Core\Config\Schema\SchemaIncompleteException
    */
   public function testToArrayFallback() {
+    $this->entityType->expects($this->any())
+      ->method('getPropertiesToExport')
+      ->willReturn([]);
     $this->entity->toArray();
   }
 
diff --git a/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityStorageTest.php b/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityStorageTest.php
index 2302eaa..e0083e4 100644
--- a/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityStorageTest.php
+++ b/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityStorageTest.php
@@ -22,7 +22,7 @@ class ConfigEntityStorageTest extends UnitTestCase {
   /**
    * The entity type.
    *
-   * @var \Drupal\Core\Entity\EntityTypeInterface|\PHPUnit_Framework_MockObject_MockObject
+   * @var \Drupal\Core\Config\Entity\ConfigEntityTypeInterface|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $entityType;
 
@@ -111,7 +111,7 @@ class ConfigEntityStorageTest extends UnitTestCase {
   protected function setUp() {
     parent::setUp();
 
-    $this->entityType = $this->getMock('Drupal\Core\Entity\EntityTypeInterface');
+    $this->entityType = $this->getMock('Drupal\Core\Config\Entity\ConfigEntityTypeInterface');
     $this->entityTypeId = 'test_entity_type';
     $this->entityType->expects($this->any())
       ->method('getKey')