diff --git a/core/modules/user/src/Tests/UserAdminLanguageTest.php b/core/modules/user/tests/src/Functional/UserAdminLanguageTest.php
similarity index 86%
rename from core/modules/user/src/Tests/UserAdminLanguageTest.php
rename to core/modules/user/tests/src/Functional/UserAdminLanguageTest.php
index cd6cc657bf..414f159770 100644
--- a/core/modules/user/src/Tests/UserAdminLanguageTest.php
+++ b/core/modules/user/tests/src/Functional/UserAdminLanguageTest.php
@@ -1,16 +1,16 @@
 <?php
 
-namespace Drupal\user\Tests;
+namespace Drupal\Tests\user\Functional;
 
 use Drupal\Core\Language\LanguageInterface;
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests users' ability to change their own administration language.
  *
  * @group user
  */
-class UserAdminLanguageTest extends WebTestBase {
+class UserAdminLanguageTest extends BrowserTestBase {
 
   /**
    * A user with permission to access admin pages and administer languages.
@@ -50,7 +50,7 @@ public function testUserAdminLanguageConfigurationNotAvailableWithOnlyOneLanguag
     $path = 'user/' . $this->adminUser->id() . '/edit';
     $this->drupalGet($path);
     // Ensure administration pages language settings widget is not available.
-    $this->assertNoFieldByXPath($this->constructFieldXpath('id', 'edit-preferred-admin-langcode'), NULL, 'Administration pages language selector not available.');
+    $this->assertNull($this->getSession()->getPage()->findField('edit-preferred-admin-langcode'));
   }
 
   /**
@@ -64,13 +64,13 @@ public function testUserAdminLanguageConfigurationAvailableWithAdminLanguageNego
     // Checks with user administration pages language negotiation disabled.
     $this->drupalGet($path);
     // Ensure administration pages language settings widget is not available.
-    $this->assertNoFieldByXPath($this->constructFieldXpath('id', 'edit-preferred-admin-langcode'), NULL, 'Administration pages language selector not available.');
+    $this->assertNull($this->getSession()->getPage()->findField('edit-preferred-admin-langcode'));
 
     // Checks with user administration pages language negotiation enabled.
     $this->setLanguageNegotiation();
     $this->drupalGet($path);
     // Ensure administration pages language settings widget is available.
-    $this->assertFieldByXPath($this->constructFieldXpath('id', 'edit-preferred-admin-langcode'), NULL, 'Administration pages language selector is available.');
+    $this->assertNotNull($this->getSession()->getPage()->findField('edit-preferred-admin-langcode'));
   }
 
   /**
@@ -91,13 +91,13 @@ public function testUserAdminLanguageConfigurationAvailableIfAdminLanguageNegoti
     $path = 'user/' . $this->adminUser->id() . '/edit';
     $this->drupalGet($path);
     // Ensure administration pages language setting is visible for admin.
-    $this->assertFieldByXPath($this->constructFieldXpath('id', 'edit-preferred-admin-langcode'), NULL, 'Administration pages language selector available for admins.');
+    $this->assertNotNull($this->getSession()->getPage()->findField( 'edit-preferred-admin-langcode'));
 
     // Ensure administration pages language setting is hidden for non-admins.
     $this->drupalLogin($this->regularUser);
     $path = 'user/' . $this->regularUser->id() . '/edit';
     $this->drupalGet($path);
-    $this->assertNoFieldByXPath($this->constructFieldXpath('id', 'edit-preferred-admin-langcode'), NULL, 'Administration pages language selector not available for regular user.');
+    $this->assertNull($this->getSession()->getPage()->findField('edit-preferred-admin-langcode'));
   }
 
   /**
diff --git a/core/modules/user/src/Tests/UserBlocksTest.php b/core/modules/user/tests/src/Functional/UserBlocksTest.php
similarity index 71%
rename from core/modules/user/src/Tests/UserBlocksTest.php
rename to core/modules/user/tests/src/Functional/UserBlocksTest.php
index 0a4c619da6..6c2ae97609 100644
--- a/core/modules/user/src/Tests/UserBlocksTest.php
+++ b/core/modules/user/tests/src/Functional/UserBlocksTest.php
@@ -1,16 +1,16 @@
 <?php
 
-namespace Drupal\user\Tests;
+namespace Drupal\Tests\user\Functional;
 
 use Drupal\dynamic_page_cache\EventSubscriber\DynamicPageCacheSubscriber;
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests user blocks.
  *
  * @group user
  */
-class UserBlocksTest extends WebTestBase {
+class UserBlocksTest extends BrowserTestBase {
 
   /**
    * Modules to enable.
@@ -69,7 +69,7 @@ public function testUserLoginBlock() {
     // Log in using the block.
     $edit = [];
     $edit['name'] = $user->getUsername();
-    $edit['pass'] = $user->pass_raw;
+    $edit['pass'] = $user->passRaw;
     $this->drupalPostForm('admin/people/permissions', $edit, t('Log in'));
     $this->assertNoText(t('User login'), 'Logged in.');
 
@@ -121,46 +121,4 @@ public function testUserLoginBlock() {
     $this->assertNoText(t('Unrecognized username or password. Forgot your password?'));
   }
 
-  /**
-   * Test the Who's Online block.
-   */
-  public function testWhosOnlineBlock() {
-    $block = $this->drupalPlaceBlock('views_block:who_s_online-who_s_online_block');
-
-    // Generate users.
-    $user1 = $this->drupalCreateUser(['access user profiles']);
-    $user2 = $this->drupalCreateUser([]);
-    $user3 = $this->drupalCreateUser([]);
-
-    // Update access of two users to be within the active timespan.
-    $this->updateAccess($user1->id());
-    $this->updateAccess($user2->id(), REQUEST_TIME + 1);
-
-    // Insert an inactive user who should not be seen in the block, and ensure
-    // that the admin user used in setUp() does not appear.
-    $inactive_time = REQUEST_TIME - (15 * 60) - 1;
-    $this->updateAccess($user3->id(), $inactive_time);
-    $this->updateAccess($this->adminUser->id(), $inactive_time);
-
-    // Test block output.
-    \Drupal::currentUser()->setAccount($user1);
-    $content = entity_view($block, 'block');
-    $this->setRawContent(\Drupal::service('renderer')->renderRoot($content));
-    $this->assertRaw(t('2 users'), 'Correct number of online users (2 users).');
-    $this->assertText($user1->getUsername(), 'Active user 1 found in online list.');
-    $this->assertText($user2->getUsername(), 'Active user 2 found in online list.');
-    $this->assertNoText($user3->getUsername(), 'Inactive user not found in online list.');
-    $this->assertTrue(strpos($this->getRawContent(), $user1->getUsername()) > strpos($this->getRawContent(), $user2->getUsername()), 'Online users are ordered correctly.');
-  }
-
-  /**
-   * Updates the access column for a user.
-   */
-  private function updateAccess($uid, $access = REQUEST_TIME) {
-    db_update('users_field_data')
-      ->condition('uid', $uid)
-      ->fields(['access' => $access])
-      ->execute();
-  }
-
 }
diff --git a/core/modules/user/src/Tests/UserCreateTest.php b/core/modules/user/tests/src/Functional/UserCreateTest.php
similarity index 94%
rename from core/modules/user/src/Tests/UserCreateTest.php
rename to core/modules/user/tests/src/Functional/UserCreateTest.php
index 7b534435a0..fb7e996e3f 100644
--- a/core/modules/user/src/Tests/UserCreateTest.php
+++ b/core/modules/user/tests/src/Functional/UserCreateTest.php
@@ -1,18 +1,22 @@
 <?php
 
-namespace Drupal\user\Tests;
+namespace Drupal\Tests\user\Functional;
 
 use Drupal\field\Entity\FieldConfig;
-use Drupal\simpletest\WebTestBase;
 use Drupal\field\Entity\FieldStorageConfig;
+use Drupal\Tests\BrowserTestBase;
+use Drupal\Core\Test\AssertMailTrait;
 
 /**
  * Tests the create user administration page.
  *
  * @group user
  */
-class UserCreateTest extends WebTestBase {
+class UserCreateTest extends BrowserTestBase {
 
+  use AssertMailTrait {
+    getMails as drupalGetMails;
+  }
   /**
    * Modules to enable.
    *
@@ -109,7 +113,7 @@ public function testUserAdd() {
       $this->drupalGet('admin/people');
       $this->assertText($edit['name'], 'User found in list of users');
       $user = user_load_by_name($name);
-      $this->assertEqual($user->isActive(), 'User is not blocked');
+      $this->assertTrue($user->isActive(), 'User is not blocked');
     }
 
     // Test that the password '0' is considered a password.
diff --git a/core/modules/user/src/Tests/UserPasswordResetTest.php b/core/modules/user/tests/src/Functional/UserPasswordResetTest.php
similarity index 97%
rename from core/modules/user/src/Tests/UserPasswordResetTest.php
rename to core/modules/user/tests/src/Functional/UserPasswordResetTest.php
index 528d38bc96..fb25317075 100644
--- a/core/modules/user/src/Tests/UserPasswordResetTest.php
+++ b/core/modules/user/tests/src/Functional/UserPasswordResetTest.php
@@ -1,11 +1,13 @@
 <?php
 
-namespace Drupal\user\Tests;
+namespace Drupal\Tests\user\Functional;
 
 use Drupal\Component\Render\FormattableMarkup;
 use Drupal\Core\Url;
-use Drupal\system\Tests\Cache\PageCacheTagsTestBase;
+use \Drupal\Tests\system\Functional\Cache\PageCacheTagsTestBase;
 use Drupal\user\Entity\User;
+use Drupal\Core\Test\AssertMailTrait;
+use Drupal\Tests\TestFileCreationTrait;
 
 /**
  * Ensure that password reset methods work as expected.
@@ -14,6 +16,13 @@
  */
 class UserPasswordResetTest extends PageCacheTagsTestBase {
 
+  use AssertMailTrait {
+    getMails as drupalGetMails;
+  }
+  use TestFileCreationTrait {
+    getTestFiles as drupalGetTestFiles;
+  }
+
   /**
    * The profile to install as a basis for testing.
    *
@@ -54,7 +63,7 @@ protected function setUp() {
     $this->drupalLogin($account);
 
     $this->account = User::load($account->id());
-    $this->account->pass_raw = $account->pass_raw;
+    $this->account->passRaw = $account->passRaw;
     $this->drupalLogout();
 
     // Set the last login time that is used to generate the one-time link so
@@ -120,7 +129,7 @@ public function testUserPasswordReset() {
     $edit = [
       'files[user_picture_0]' => drupal_realpath($image->uri),
     ];
-    $this->drupalPostAjaxForm(NULL, $edit, 'user_picture_0_upload_button');
+    $this->drupalPostForm(NULL, $edit, 'Upload');
 
     // Change the forgotten password.
     $password = user_password();
diff --git a/core/modules/user/src/Tests/UserRegistrationTest.php b/core/modules/user/tests/src/Functional/UserRegistrationTest.php
similarity index 90%
rename from core/modules/user/src/Tests/UserRegistrationTest.php
rename to core/modules/user/tests/src/Functional/UserRegistrationTest.php
index ca7a4f0c89..fb63a5d320 100644
--- a/core/modules/user/src/Tests/UserRegistrationTest.php
+++ b/core/modules/user/tests/src/Functional/UserRegistrationTest.php
@@ -1,20 +1,20 @@
 <?php
 
-namespace Drupal\user\Tests;
+namespace Drupal\Tests\user\Functional;
 
 use Drupal\Core\Entity\Entity\EntityFormDisplay;
 use Drupal\Component\Utility\SafeMarkup;
 use Drupal\Core\Field\FieldStorageDefinitionInterface;
 use Drupal\field\Entity\FieldConfig;
 use Drupal\field\Entity\FieldStorageConfig;
-use Drupal\simpletest\WebTestBase;
+use Drupal\Tests\BrowserTestBase;
 
 /**
  * Tests registration of user under different configurations.
  *
  * @group user
  */
-class UserRegistrationTest extends WebTestBase {
+class UserRegistrationTest extends BrowserTestBase {
 
   /**
    * Modules to enable.
@@ -348,35 +348,27 @@ public function testRegistrationWithUserFields() {
     // Check that the 'add more' button works.
     $field_storage->setCardinality(FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED);
     $field_storage->save();
-    foreach (['js', 'nojs'] as $js) {
-      $this->drupalGet('user/register');
-      $this->assertRegistrationFormCacheTagsWithUserFields();
-      // Add two inputs.
-      $value = rand(1, 255);
-      $edit = [];
-      $edit['test_user_field[0][value]'] = $value;
-      if ($js == 'js') {
-        $this->drupalPostAjaxForm(NULL, $edit, 'test_user_field_add_more');
-        $this->drupalPostAjaxForm(NULL, $edit, 'test_user_field_add_more');
-      }
-      else {
-        $this->drupalPostForm(NULL, $edit, t('Add another item'));
-        $this->drupalPostForm(NULL, $edit, t('Add another item'));
-      }
-      // Submit with three values.
-      $edit['test_user_field[1][value]'] = $value + 1;
-      $edit['test_user_field[2][value]'] = $value + 2;
-      $edit['name'] = $name = $this->randomMachineName();
-      $edit['mail'] = $mail = $edit['name'] . '@example.com';
-      $this->drupalPostForm(NULL, $edit, t('Create new account'));
-      // Check user fields.
-      $accounts = $this->container->get('entity_type.manager')->getStorage('user')
-        ->loadByProperties(['name' => $name, 'mail' => $mail]);
-      $new_user = reset($accounts);
-      $this->assertEqual($new_user->test_user_field[0]->value, $value, format_string('@js : The field value was correctly saved.', ['@js' => $js]));
-      $this->assertEqual($new_user->test_user_field[1]->value, $value + 1, format_string('@js : The field value was correctly saved.', ['@js' => $js]));
-      $this->assertEqual($new_user->test_user_field[2]->value, $value + 2, format_string('@js : The field value was correctly saved.', ['@js' => $js]));
-    }
+    $this->drupalGet('user/register');
+    $this->assertRegistrationFormCacheTagsWithUserFields();
+    // Add two inputs.
+    $value = random_int(1, 255);
+    $edit = [];
+    $edit['test_user_field[0][value]'] = $value;
+    $this->drupalPostForm(NULL, $edit, t('Add another item'));
+    $this->drupalPostForm(NULL, $edit, t('Add another item'));
+    // Submit with three values.
+    $edit['test_user_field[1][value]'] = $value + 1;
+    $edit['test_user_field[2][value]'] = $value + 2;
+    $edit['name'] = $name = $this->randomMachineName();
+    $edit['mail'] = $mail = $edit['name'] . '@example.com';
+    $this->drupalPostForm(NULL, $edit, t('Create new account'));
+    // Check user fields.
+    $accounts = $this->container->get('entity_type.manager')->getStorage('user')
+      ->loadByProperties(['name' => $name, 'mail' => $mail]);
+    $new_user = reset($accounts);
+    $this->assertEquals($new_user->test_user_field[0]->value, $value, t('The field value was correctly saved.'));
+    $this->assertEquals($new_user->test_user_field[1]->value, $value + 1, t('The field value was correctly saved.'));
+    $this->assertEquals($new_user->test_user_field[2]->value, $value + 2, t('The field value was correctly saved.'));
   }
 
   /**