diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Entity/Feed.php b/core/modules/aggregator/lib/Drupal/aggregator/Entity/Feed.php
index ff93c30..568cede 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Entity/Feed.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Entity/Feed.php
@@ -161,11 +161,13 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
 
     $fields['checked'] = FieldDefinition::create('timestamp')
       ->setLabel(t('Checked'))
-      ->setDescription(t('Last time feed was checked for new items, as Unix timestamp.'));
+      ->setDescription(t('Last time feed was checked for new items, as Unix timestamp.'))
+      ->setSetting('default_value', 0);
 
     $fields['queued'] = FieldDefinition::create('timestamp')
       ->setLabel(t('Queued'))
-      ->setDescription(t('Time when this feed was queued for refresh, 0 if not queued.'));
+      ->setDescription(t('Time when this feed was queued for refresh, 0 if not queued.'))
+      ->setSetting('default_value', 0);
 
     $fields['link'] = FieldDefinition::create('uri')
       ->setLabel(t('Link'))
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Entity/Item.php b/core/modules/aggregator/lib/Drupal/aggregator/Entity/Item.php
index f12ed40..804d42a 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Entity/Item.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Entity/Item.php
@@ -78,8 +78,7 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
       ->setLabel(t('Author'))
       ->setDescription(t('The author of the feed item.'));
 
-    // @todo Convert to a text field in https://drupal.org/node/2149845.
-    $fields['description'] = FieldDefinition::create('string')
+    $fields['description'] = FieldDefinition::create('string_long')
       ->setLabel(t('Description'))
       ->setDescription(t('The body of the feed item.'));
 
@@ -88,7 +87,7 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
       ->setDescription(t('Posted date of the feed item, as a Unix timestamp.'));
 
     // @todo Convert to a real UUID field in https://drupal.org/node/2149851.
-    $fields['guid'] = FieldDefinition::create('string')
+    $fields['guid'] = FieldDefinition::create('string_long')
       ->setLabel(t('GUID'))
       ->setDescription(t('Unique identifier for the feed item.'));
 
diff --git a/core/modules/field/lib/Drupal/field/Tests/FieldInfoTest.php b/core/modules/field/lib/Drupal/field/Tests/FieldInfoTest.php
index a869865..5c9c32d 100644
--- a/core/modules/field/lib/Drupal/field/Tests/FieldInfoTest.php
+++ b/core/modules/field/lib/Drupal/field/Tests/FieldInfoTest.php
@@ -177,7 +177,6 @@ function testInstancePrepare() {
   function testInstanceDisabledEntityType() {
     // Disabling a module invokes user_modules_uninstalled() and calls
     // drupal_flush_all_caches(). Install the necessary schema to support this.
-    $this->installEntitySchema('user');
     $this->installSchema('system', array('router'));
 
     // For this test the field type and the entity type must be exposed by
diff --git a/core/modules/file/lib/Drupal/file/Tests/FileManagedUnitTestBase.php b/core/modules/file/lib/Drupal/file/Tests/FileManagedUnitTestBase.php
index 56a2940..1930297 100644
--- a/core/modules/file/lib/Drupal/file/Tests/FileManagedUnitTestBase.php
+++ b/core/modules/file/lib/Drupal/file/Tests/FileManagedUnitTestBase.php
@@ -161,20 +161,19 @@ function assertSameFile(FileInterface $file1, FileInterface $file2) {
    *   File entity.
    */
   function createFile($filepath = NULL, $contents = NULL, $scheme = NULL) {
-    $file = new \stdClass();
-    $file->uri = $this->createUri($filepath, $contents, $scheme);
-    $file->filename = drupal_basename($file->uri);
-    $file->filemime = 'text/plain';
-    $file->uid = 1;
-    $file->created = REQUEST_TIME;
-    $file->changed = REQUEST_TIME;
-    $file->filesize = filesize($file->uri);
-    $file->status = 0;
+    // Don't count hook invocations caused by creating the file.
+    \Drupal::state()->set('file_test.count_hook_invocations', FALSE);
+    $file = entity_create('file', array(
+      'uri' => $this->createUri($filepath, $contents, $scheme),
+      'uid' => 1,
+    ));
+    $file->save();
     // Write the record directly rather than using the API so we don't invoke
     // the hooks.
-    $this->assertNotIdentical(drupal_write_record('file_managed', $file), FALSE, 'The file was added to the database.', 'Create test file');
+    $this->assertTrue($file->id() > 0, 'The file was added to the database.', 'Create test file');
 
-    return entity_create('file', (array) $file);
+    \Drupal::state()->set('file_test.count_hook_invocations', TRUE);
+    return $file;
   }
 
   /**
diff --git a/core/modules/file/tests/file_test/file_test.module b/core/modules/file/tests/file_test/file_test.module
index e5a10a0..5fcd15f 100644
--- a/core/modules/file/tests/file_test/file_test.module
+++ b/core/modules/file/tests/file_test/file_test.module
@@ -108,9 +108,11 @@ function file_test_get_all_calls() {
  * @see file_test_reset()
  */
 function _file_test_log_call($op, $args) {
-  $results = \Drupal::state()->get('file_test.results') ?: array();
-  $results[$op][] = $args;
-  \Drupal::state()->set('file_test.results', $results);
+  if (\Drupal::state()->get('file_test.count_hook_invocations', TRUE)) {
+    $results = \Drupal::state()->get('file_test.results') ?: array();
+    $results[$op][] = $args;
+    \Drupal::state()->set('file_test.results', $results);
+  }
 }
 
 /**
diff --git a/core/modules/forum/forum.install b/core/modules/forum/forum.install
index b281d5b..3cba341 100644
--- a/core/modules/forum/forum.install
+++ b/core/modules/forum/forum.install
@@ -82,7 +82,7 @@ function forum_install() {
  * Implements hook_entity_schema_installed().
  */
 function forum_entity_schema_installed(array $storages) {
-  if (isset($installed['taxonomy_term'])) {
+  if (isset($storages['taxonomy_term'])) {
     // Create a default forum so forum posts can be created.
     $storages['taxonomy_term']->create(array(
       'name' => t('General discussion'),
diff --git a/core/modules/hal/lib/Drupal/hal/Tests/EntityTest.php b/core/modules/hal/lib/Drupal/hal/Tests/EntityTest.php
index 026f6df..15342ec 100644
--- a/core/modules/hal/lib/Drupal/hal/Tests/EntityTest.php
+++ b/core/modules/hal/lib/Drupal/hal/Tests/EntityTest.php
@@ -39,7 +39,6 @@ function setUp() {
     \Drupal::service('router.builder')->rebuild();
     $this->installSchema('system', array('sequences'));
     $this->installEntitySchema('node');
-    $this->installEntitySchema('user');
     $this->installEntitySchema('taxonomy_term');
   }
 
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/Tests/DrupalUnitTestBaseTest.php b/core/modules/simpletest/lib/Drupal/simpletest/Tests/DrupalUnitTestBaseTest.php
index 40c16fd..e968c2f 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/Tests/DrupalUnitTestBaseTest.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/Tests/DrupalUnitTestBaseTest.php
@@ -109,7 +109,7 @@ function testEnableModulesInstall() {
    */
   function testEnableModulesInstallContainer() {
     // Install Node module.
-    $this->enableModules(array('field', 'node'));
+    $this->enableModules(array('field', 'node', 'user'));
 
     $this->installEntitySchema('node');
     // Perform an entity query against node.
diff --git a/core/modules/system/lib/Drupal/system/Tests/Common/WriteRecordTest.php b/core/modules/system/lib/Drupal/system/Tests/Common/WriteRecordTest.php
index ffe5fdb..da88eda 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Common/WriteRecordTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Common/WriteRecordTest.php
@@ -7,19 +7,20 @@
 
 namespace Drupal\system\Tests\Common;
 
+use Drupal\simpletest\DrupalUnitTestBase;
 use Drupal\simpletest\WebTestBase;
 
 /**
  * Tests writing of data records with drupal_write_record().
  */
-class WriteRecordTest extends WebTestBase {
+class WriteRecordTest extends DrupalUnitTestBase {
 
   /**
    * Modules to enable.
    *
    * @var array
    */
-  public static $modules = array('database_test', 'node');
+  public static $modules = array('database_test');
 
   public static function getInfo() {
     return array(
@@ -33,6 +34,8 @@ public static function getInfo() {
    * Tests the drupal_write_record() API function.
    */
   function testDrupalWriteRecord() {
+    $this->installSchema('database_test', array('test', 'test_null', 'test_serialized', 'test_composite_primary'));
+
     // Insert a record with no columns populated.
     $record = array();
     $insert_result = drupal_write_record('test', $record);
@@ -135,15 +138,14 @@ function testDrupalWriteRecord() {
     $this->assertTrue($update_result == SAVED_UPDATED, 'Correct value returned when a valid update is run without changing any values.');
 
     // Insert an object record for a table with a multi-field primary key.
-    $node_access = new \stdClass();
-    $node_access->nid = mt_rand();
-    $node_access->gid = mt_rand();
-    $node_access->realm = $this->randomName();
-    $insert_result = drupal_write_record('node_access', $node_access);
+    $composite_primary = new \stdClass();
+    $composite_primary->name = $this->randomName();
+    $composite_primary->age = mt_rand();
+    $insert_result = drupal_write_record('test_composite_primary', $composite_primary);
     $this->assertTrue($insert_result == SAVED_NEW, 'Correct value returned when a record is inserted with drupal_write_record() for a table with a multi-field primary key.');
 
     // Update the record.
-    $update_result = drupal_write_record('node_access', $node_access, array('nid', 'gid', 'realm'));
+    $update_result = drupal_write_record('test_composite_primary', $composite_primary, array('name', 'job'));
     $this->assertTrue($update_result == SAVED_UPDATED, 'Correct value returned when a record is updated with drupal_write_record() for a table with a multi-field primary key.');
   }
 
diff --git a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityFieldTest.php b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityFieldTest.php
index fa80432..36b3655 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityFieldTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityFieldTest.php
@@ -41,7 +41,6 @@ public static function getInfo() {
   public function setUp() {
     parent::setUp();
 
-    $this->installSchema('node', array('node_access'));
     $this->installEntitySchema('node');
 
     $this->installEntitySchema('entity_test_rev');
diff --git a/core/modules/system/lib/Drupal/system/Tests/Entity/FieldAccessTest.php b/core/modules/system/lib/Drupal/system/Tests/Entity/FieldAccessTest.php
index 8ab706c..d72b297 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Entity/FieldAccessTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Entity/FieldAccessTest.php
@@ -46,6 +46,7 @@ protected function setUp() {
     // The users table is needed for creating dummy user accounts.
     $this->installEntitySchema('user');
     // Register entity_test text field.
+    module_load_install('entity_test');
     entity_test_install();
   }
 
diff --git a/core/modules/system/tests/modules/database_test/database_test.install b/core/modules/system/tests/modules/database_test/database_test.install
index 866d453..7c74c1c 100644
--- a/core/modules/system/tests/modules/database_test/database_test.install
+++ b/core/modules/system/tests/modules/database_test/database_test.install
@@ -245,5 +245,34 @@ function database_test_schema() {
     ),
   );
 
+  $schema['test_composite_primary'] = array(
+    'description' => 'Basic test table with a composite primary key',
+    'fields' => array(
+      'name' => array(
+        'description' => "A person's name",
+        'type' => 'varchar',
+        'length' => 50,
+        'not null' => TRUE,
+        'default' => '',
+        'binary' => TRUE,
+      ),
+      'age' => array(
+        'description' => "The person's age",
+        'type' => 'int',
+        'unsigned' => TRUE,
+        'not null' => TRUE,
+        'default' => 0,
+      ),
+      'job' => array(
+        'description' => "The person's job",
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => TRUE,
+        'default' => 'Undefined',
+      ),
+    ),
+    'primary key' => array('name', 'age'),
+  );
+
   return $schema;
 }
diff --git a/core/modules/taxonomy/lib/Drupal/taxonomy/Tests/TaxonomyTermReferenceItemTest.php b/core/modules/taxonomy/lib/Drupal/taxonomy/Tests/TaxonomyTermReferenceItemTest.php
index 0dbdd35..78c877f 100644
--- a/core/modules/taxonomy/lib/Drupal/taxonomy/Tests/TaxonomyTermReferenceItemTest.php
+++ b/core/modules/taxonomy/lib/Drupal/taxonomy/Tests/TaxonomyTermReferenceItemTest.php
@@ -42,7 +42,7 @@ public static function getInfo() {
 
   public function setUp() {
     parent::setUp();
-    $this->installEntitySchema('taxonomy');
+    $this->installEntitySchema('taxonomy_term');
 
     $vocabulary = entity_create('taxonomy_vocabulary', array(
       'name' => $this->randomName(),