diff --git a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
index 0a5cc0a..32db6c5 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
@@ -14,6 +14,7 @@
 use Drupal\Core\Database\Database;
 use Drupal\Core\Database\ConnectionNotDefinedException;
 use Drupal\Core\Language\Language;
+use Drupal\Core\Session\AccountInterface;
 use Drupal\Core\Session\UserSession;
 use PDO;
 use stdClass;
@@ -615,12 +616,12 @@ protected function checkPermissions(array $permissions, $reset = FALSE) {
    *   $account->pass_raw = $pass_raw;
    * @endcode
    *
-   * @param \Drupal\user\UserInterface $account
+   * @param \Drupal\Core\Session\AccountInterface $account
    *   User object representing the user to log in.
    *
    * @see drupalCreateUser()
    */
-  protected function drupalLogin($account) {
+  protected function drupalLogin(AccountInterface $account) {
     if ($this->loggedInUser) {
       $this->drupalLogout();
     }
diff --git a/core/modules/system/lib/Drupal/system/Tests/System/PasswordHashingTest.php b/core/modules/system/lib/Drupal/system/Tests/System/PasswordHashingTest.php
index 10ec647..7b61c15 100644
--- a/core/modules/system/lib/Drupal/system/Tests/System/PasswordHashingTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/System/PasswordHashingTest.php
@@ -7,13 +7,21 @@
 
 namespace Drupal\system\Tests\System;
 
-use Drupal\simpletest\UnitTestBase;
+use Drupal\simpletest\DrupalUnitTestBase;
 use Drupal\Core\Password\PhpassHashedPassword;
 
 /**
  * Unit tests for password hashing API.
  */
-class PasswordHashingTest extends UnitTestBase {
+class PasswordHashingTest extends DrupalUnitTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('user');
+
   public static function getInfo() {
     return array(
       'name' => 'Password hashing',
@@ -31,13 +39,13 @@ function testPasswordHashing() {
     $password_hasher = new PhpassHashedPassword(1);
     // Set up a fake $account with a password 'baz', hashed with md5.
     $password = 'baz';
-    $account = (object) array('name' => 'foo', 'pass' => md5($password));
+    $account = entity_create('user', array('name' => 'foo', 'pass' => md5($password)));
     // The md5 password should be flagged as needing an update.
     $this->assertTrue($password_hasher->userNeedsNewHash($account), 'User with md5 password needs a new hash.');
     // Re-hash the password.
     $old_hash = $account->getPassword();
-    $account->pass = $password_hasher->hash($password);
-    $this->assertIdentical($password_hasher->getCountLog2($account->pass), $password_hasher::MIN_HASH_COUNT, 'Re-hashed password has the minimum number of log2 iterations.');
+    $account->setPassword($password_hasher->hash($password));
+    $this->assertIdentical($password_hasher->getCountLog2($account->getPassword()), $password_hasher::MIN_HASH_COUNT, 'Re-hashed password has the minimum number of log2 iterations.');
     $this->assertTrue($account->getPassword() != $old_hash, 'Password hash changed.');
     $this->assertTrue($password_hasher->check($password, $account), 'Password check succeeds.');
     // Since the log2 setting hasn't changed and the user has a valid password,
@@ -49,8 +57,8 @@ function testPasswordHashing() {
     $this->assertTrue($password_hasher->userNeedsNewHash($account), 'User needs a new hash after incrementing the log2 count.');
     // Re-hash the password.
     $old_hash = $account->getPassword();
-    $account->pass = $password_hasher->hash($password);
-    $this->assertIdentical($password_hasher->getCountLog2($account->pass), $password_hasher::MIN_HASH_COUNT + 1, 'Re-hashed password has the correct number of log2 iterations.');
+    $account->setPassword($password_hasher->hash($password));
+    $this->assertIdentical($password_hasher->getCountLog2($account->getPassword()), $password_hasher::MIN_HASH_COUNT + 1, 'Re-hashed password has the correct number of log2 iterations.');
     $this->assertTrue($account->getPassword() != $old_hash, 'Password hash changed again.');
     // Now the hash should be OK.
     $this->assertFalse($password_hasher->userNeedsNewHash($account), 'Re-hashed password does not need a new hash.');
diff --git a/core/modules/system/lib/Drupal/system/Tests/Upgrade/BareMinimalUpgradePathTest.php b/core/modules/system/lib/Drupal/system/Tests/Upgrade/BareMinimalUpgradePathTest.php
index b6feee4..2abff85 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Upgrade/BareMinimalUpgradePathTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Upgrade/BareMinimalUpgradePathTest.php
@@ -7,6 +7,8 @@
 
 namespace Drupal\system\Tests\Upgrade;
 
+use Drupal\Core\Session\UserSession;
+
 /**
  * Performs major version release upgrade tests on a bare database.
  *
@@ -45,20 +47,17 @@ public function testBasicMinimalUpgrade() {
 
     // Verify that we are still logged in.
     $this->finishUpgradeSession();
-    $this->drupalLogin((object) array(
+    $user = new UserSession(array(
       'uid' => 1,
       'name' => 'admin',
       'pass_raw' => 'drupal',
     ));
+    $this->drupalLogin($user);
 
     // The previous login should've triggered a password rehash, so login one
     // more time to make sure the new hash is readable.
     $this->drupalLogout();
-    $this->drupalLogin((object) array(
-      'uid' => 1,
-      'name' => 'admin',
-      'pass_raw' => 'drupal',
-    ));
+    $this->drupalLogin($user);
 
     // Test that the site name is correctly displayed.
     $this->assertText('drupal', 'The site name is correctly displayed.');
diff --git a/core/modules/system/lib/Drupal/system/Tests/Upgrade/BareStandardUpgradePathTest.php b/core/modules/system/lib/Drupal/system/Tests/Upgrade/BareStandardUpgradePathTest.php
index 148156e..37ad031 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Upgrade/BareStandardUpgradePathTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Upgrade/BareStandardUpgradePathTest.php
@@ -7,6 +7,8 @@
 
 namespace Drupal\system\Tests\Upgrade;
 
+use Drupal\Core\Session\UserSession;
+
 /**
  * Performs major version release upgrade tests on a bare database.
  *
@@ -50,20 +52,17 @@ public function testBasicStandardUpgrade() {
 
     // Logout and verify that we can login back in with our initial password.
     $this->drupalLogout();
-    $this->drupalLogin((object) array(
+    $user = new UserSession(array(
       'uid' => 1,
       'name' => 'admin',
       'pass_raw' => 'drupal',
     ));
+    $this->drupalLogin($user);
 
     // The previous login should've triggered a password rehash, so login one
     // more time to make sure the new hash is readable.
     $this->drupalLogout();
-    $this->drupalLogin((object) array(
-      'uid' => 1,
-      'name' => 'admin',
-      'pass_raw' => 'drupal',
-    ));
+    $this->drupalLogin($user);
 
     // Test that the site name is correctly displayed.
     $this->assertText('drupal', 'The site name is correctly displayed.');
diff --git a/core/modules/system/lib/Drupal/system/Tests/Upgrade/FilledMinimalUpgradePathTest.php b/core/modules/system/lib/Drupal/system/Tests/Upgrade/FilledMinimalUpgradePathTest.php
index 4e28e13..86d2b10 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Upgrade/FilledMinimalUpgradePathTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Upgrade/FilledMinimalUpgradePathTest.php
@@ -7,6 +7,8 @@
 
 namespace Drupal\system\Tests\Upgrade;
 
+use Drupal\Core\Session\UserSession;
+
 /**
  * Performs major version release upgrade tests on a populated database.
  *
@@ -49,20 +51,17 @@ public function testFilledMinimalUpgrade() {
 
     // Logout and verify that we can login back in with our initial password.
     $this->drupalLogout();
-    $this->drupalLogin((object) array(
+    $user = new UserSession(array(
       'uid' => 1,
       'name' => 'admin',
       'pass_raw' => 'drupal',
     ));
+    $this->drupalLogin($user);
 
     // The previous login should've triggered a password rehash, so login one
     // more time to make sure the new hash is readable.
     $this->drupalLogout();
-    $this->drupalLogin((object) array(
-      'uid' => 1,
-      'name' => 'admin',
-      'pass_raw' => 'drupal',
-    ));
+    $this->drupalLogin($user);
 
     // Test that the site name is correctly displayed.
     $this->assertText('drupal', 'The site name is correctly displayed.');
diff --git a/core/modules/system/lib/Drupal/system/Tests/Upgrade/FilledStandardUpgradePathTest.php b/core/modules/system/lib/Drupal/system/Tests/Upgrade/FilledStandardUpgradePathTest.php
index 9fedb35..0064c4c 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Upgrade/FilledStandardUpgradePathTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Upgrade/FilledStandardUpgradePathTest.php
@@ -7,6 +7,8 @@
 
 namespace Drupal\system\Tests\Upgrade;
 
+use Drupal\Core\Session\UserSession;
+
 /**
  * Performs major version release upgrade tests on a populated database.
  *
@@ -62,20 +64,17 @@ public function testFilledStandardUpgrade() {
 
     // Logout and verify that we can login back in with our initial password.
     $this->drupalLogout();
-    $this->drupalLogin((object) array(
+    $user = new UserSession(array(
       'uid' => 1,
       'name' => 'admin',
       'pass_raw' => 'drupal',
     ));
+    $this->drupalLogin($user);
 
     // The previous login should've triggered a password rehash, so login one
     // more time to make sure the new hash is readable.
     $this->drupalLogout();
-    $this->drupalLogin((object) array(
-      'uid' => 1,
-      'name' => 'admin',
-      'pass_raw' => 'drupal',
-    ));
+    $this->drupalLogin($user);
 
     // Test that the site name is correctly displayed.
     $this->assertText('drupal', 'The site name is correctly displayed.');
diff --git a/core/modules/user/lib/Drupal/user/UserAutocomplete.php b/core/modules/user/lib/Drupal/user/UserAutocomplete.php
index a935200..4d36923 100644
--- a/core/modules/user/lib/Drupal/user/UserAutocomplete.php
+++ b/core/modules/user/lib/Drupal/user/UserAutocomplete.php
@@ -67,7 +67,7 @@ public function getMatches($string, $include_anonymous = FALSE) {
       }
       $result = $this->connection->select('users')->fields('users', array('name'))->condition('name', db_like($string) . '%', 'LIKE')->range(0, 10)->execute();
       foreach ($result as $account) {
-        $matches[$account->getUsername()] = check_plain($account->getUsername());
+        $matches[$account->name] = check_plain($account->name);
       }
     }
 
diff --git a/core/modules/user/lib/Drupal/user/UserBCDecorator.php b/core/modules/user/lib/Drupal/user/UserBCDecorator.php
index 7a5026b..320c0f9 100644
--- a/core/modules/user/lib/Drupal/user/UserBCDecorator.php
+++ b/core/modules/user/lib/Drupal/user/UserBCDecorator.php
@@ -171,7 +171,7 @@ public function setLastLoginTime($timestamp) {
    * {@inheritdoc}
    */
   public function isActive() {
-    $this->decorated->isActive();
+    return $this->decorated->isActive();
   }
 
   /**