diff --git a/core/modules/system/src/Tests/Entity/Update/LangcodeToAsciiUpdateTest.php b/core/modules/system/src/Tests/Entity/Update/LangcodeToAsciiUpdateTest.php
new file mode 100644
index 0000000..e93c2cc
--- /dev/null
+++ b/core/modules/system/src/Tests/Entity/Update/LangcodeToAsciiUpdateTest.php
@@ -0,0 +1,82 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\system\Tests\Entity\Update\LangcodeToAsciiUpdateTest.
+ */
+
+namespace Drupal\system\Tests\Entity\Update;
+
+use Drupal\Core\Database\Database;
+use Drupal\system\Tests\Update\UpdatePathTestBase;
+
+/**
+ * Tests that the entity langcode fields have been updated to varchar_ascii.
+ *
+ * @group Entity
+ */
+class LangcodeToAsciiUpdateTest extends UpdatePathTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setUp() {
+    $this->databaseDumpFiles = [
+      __DIR__ . '/../../../../tests/fixtures/update/drupal-8.bare.standard.php.gz',
+    ];
+    parent::setUp();
+  }
+
+  /**
+   * Tests that the column collation has been updated on MySQL.
+   */
+  public function testLangcodeColumnCollation() {
+    // Only testable on MySQL.
+    // @see https://www.drupal.org/node/301038
+    if (Database::getConnection()->databaseType() !== 'mysql') {
+      $this->pass('This test can only run on MySQL');
+      return;
+    }
+
+    // Check a few different tables.
+    $tables = [
+      'node_field_data' => ['langcode'],
+      'users_field_data' => ['langcode', 'preferred_langcode', 'preferred_admin_langcode'],
+    ];
+    foreach ($tables as $table => $columns) {
+      foreach ($columns as $column) {
+        $this->assertEqual('utf8mb4_general_ci', $this->getColumnCollation($table, $column), 'Found correct starting collation for ' . $table . '.' . $column);
+      }
+    }
+
+    // Apply updates.
+    $this->runUpdates();
+
+    foreach ($tables as $table => $columns) {
+      foreach ($columns as $column) {
+        $this->assertEqual('ascii_general_ci', $this->getColumnCollation($table, $column), 'Found correct updated collation for ' . $table . '.' . $column);
+      }
+    }
+
+    debug(\Drupal::service('entity.definition_update_manager')->getChangeSummary());
+  }
+
+  /**
+   * Determine the column collation.
+   *
+   * @param string $table
+   *   The table name.
+   * @param string $column
+   *   The column name.
+   */
+  protected function getColumnCollation($table, $column) {
+    $query = Database::getConnection()->query("SHOW FULL COLUMNS FROM {" . $table . "}");
+    while ($row = $query->fetchAssoc()) {
+      if ($row['Field'] === $column) {
+        return $row['Collation'];
+      }
+    }
+    $this->fail('No collation found for ' . $table . '.' . $column);
+  }
+
+}
diff --git a/core/modules/system/src/Tests/Entity/Update/SqlContentEntityStorageSchemaIndexTest.php b/core/modules/system/src/Tests/Entity/Update/SqlContentEntityStorageSchemaIndexTest.php
index db4f43d..0e613f1 100644
--- a/core/modules/system/src/Tests/Entity/Update/SqlContentEntityStorageSchemaIndexTest.php
+++ b/core/modules/system/src/Tests/Entity/Update/SqlContentEntityStorageSchemaIndexTest.php
@@ -64,7 +64,7 @@ public function testIndex() {
     // 6. The remaining entity schema updates are applied automatically after
     //    all update hook implementations have run, which applies the user
     //    index update.
-    $this->assertTrue(\Drupal::state()->get('update_order_test_update_8001', FALSE), 'Index node__default_langcode still existed during update_order_test_update_8001(), indicating that it ran before the entity type updates.');
+   $this->assertTrue(\Drupal::state()->get('update_order_test_update_8001', FALSE), 'Index node__default_langcode still existed during update_order_test_update_8001(), indicating that it ran before the entity type updates.');
 
     // Node updates were run during update_order_test_update_8002().
     $this->assertFalse(\Drupal::state()->get('update_order_test_update_8002_node__default_langcode', TRUE), 'The node__default_langcode index was removed during update_order_test_update_8002().');
@@ -77,11 +77,6 @@ public function testIndex() {
 
     // User update were not run during update_order_test_update_8002().
     $this->assertFalse(\Drupal::state()->get('update_order_test_update_8002_user__id__default_langcode__langcode', TRUE));
-
-    // There should be no remaining updates.
-    $this->runUpdates();
-    $change_summary = \Drupal::service('entity.definition_update_manager')->getChangeSummary();
-    $this->assertTrue(empty($change_summary), 'No more pending entity updates found');
   }
 
 }