diff --git a/core/modules/update/src/Tests/UpdateTestBase.php b/core/modules/update/src/Tests/UpdateTestBase.php
index fc39d1a3cce..e243d0b867f 100644
--- a/core/modules/update/src/Tests/UpdateTestBase.php
+++ b/core/modules/update/src/Tests/UpdateTestBase.php
@@ -2,6 +2,8 @@
 
 namespace Drupal\update\Tests;
 
+@trigger_error(__NAMESPACE__ . '\UpdateTestBase is deprecated in Drupal 8.4.0 and will be removed before Drupal 9.0.0. Instead, use \Drupal\Tests\update\Functional\UpdateTestBase', E_USER_DEPRECATED);
+
 use Drupal\Core\DrupalKernel;
 use Drupal\Core\Url;
 use Drupal\simpletest\WebTestBase;
@@ -22,6 +24,9 @@ use Drupal\simpletest\WebTestBase;
  * (via the 'update_test_xml_map' variable), and then performs a series of
  * assertions that the report matches our expectations given the specific
  * initial state and availability scenario.
+ *
+ * @deprecated Scheduled for removal in Drupal 9.0.0.
+ *   Use \Drupal\Tests\update\Functional\UpdateTestBase instead.
  */
 abstract class UpdateTestBase extends WebTestBase {
 
@@ -58,7 +63,7 @@ abstract class UpdateTestBase extends WebTestBase {
    *   (optional) A string containing the URL to fetch update data from.
    *   Defaults to 'update-test'.
    *
-   * @see Drupal\update_test\Controller\UpdateTestController::updateTest()
+   * @see \Drupal\update_test\Controller\UpdateTestController::updateTest()
    */
   protected function refreshUpdateStatus($xml_map, $url = 'update-test') {
     // Tell the Update Manager module to fetch from the URL provided by
diff --git a/core/modules/update/src/Tests/FileTransferAuthorizeFormTest.php b/core/modules/update/tests/src/Functional/FileTransferAuthorizeFormTest.php
similarity index 92%
rename from core/modules/update/src/Tests/FileTransferAuthorizeFormTest.php
rename to core/modules/update/tests/src/Functional/FileTransferAuthorizeFormTest.php
index 9d1819fca3d..d768b06d818 100644
--- a/core/modules/update/src/Tests/FileTransferAuthorizeFormTest.php
+++ b/core/modules/update/tests/src/Functional/FileTransferAuthorizeFormTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\update\Tests;
+namespace Drupal\Tests\update\Functional;
 
 /**
  * Tests the Update Manager module upload via authorize.php functionality.
@@ -23,7 +23,7 @@ class FileTransferAuthorizeFormTest extends UpdateTestBase {
 
     // Create a local cache so the module is not downloaded from drupal.org.
     $cache_directory = _update_manager_cache_directory(TRUE);
-    $validArchiveFile = __DIR__ . '/../../tests/update_test_new_module/8.x-1.0/update_test_new_module.tar.gz';
+    $validArchiveFile = __DIR__ . '/../../update_test_new_module/8.x-1.0/update_test_new_module.tar.gz';
     copy($validArchiveFile, $cache_directory . '/update_test_new_module.tar.gz');
   }
 
diff --git a/core/modules/update/src/Tests/UpdateContribTest.php b/core/modules/update/tests/src/Functional/UpdateContribTest.php
similarity index 99%
rename from core/modules/update/src/Tests/UpdateContribTest.php
rename to core/modules/update/tests/src/Functional/UpdateContribTest.php
index 81f7117a3ac..20d397cd482 100644
--- a/core/modules/update/src/Tests/UpdateContribTest.php
+++ b/core/modules/update/tests/src/Functional/UpdateContribTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\update\Tests;
+namespace Drupal\Tests\update\Functional;
 
 use Drupal\Core\Url;
 use Drupal\Core\Utility\ProjectInfo;
diff --git a/core/modules/update/src/Tests/UpdateCoreTest.php b/core/modules/update/tests/src/Functional/UpdateCoreTest.php
similarity index 98%
rename from core/modules/update/src/Tests/UpdateCoreTest.php
rename to core/modules/update/tests/src/Functional/UpdateCoreTest.php
index b6287c7c04d..5cd4b102606 100644
--- a/core/modules/update/src/Tests/UpdateCoreTest.php
+++ b/core/modules/update/tests/src/Functional/UpdateCoreTest.php
@@ -1,8 +1,9 @@
 <?php
 
-namespace Drupal\update\Tests;
+namespace Drupal\Tests\update\Functional;
 
 use Drupal\Core\Url;
+use Drupal\Tests\Traits\Core\CronRunTrait;
 
 /**
  * Tests the Update Manager module through a series of functional tests using
@@ -12,6 +13,8 @@ use Drupal\Core\Url;
  */
 class UpdateCoreTest extends UpdateTestBase {
 
+  use CronRunTrait;
+
   /**
    * Modules to enable.
    *
@@ -76,6 +79,7 @@ class UpdateCoreTest extends UpdateTestBase {
         $this->standardTests();
         $this->drupalGet('admin/reports/updates');
         $this->clickLink(t('Check manually'));
+        $this->checkForMetaRefresh();
         $this->assertNoText(t('Security update required!'));
         $this->assertRaw(\Drupal::l("8.$minor_version.1" . $extra_version, Url::fromUri("http://example.com/drupal-8-$minor_version-1$extra_version-release")), 'Link to release appears.');
         $this->assertRaw(\Drupal::l(t('Download'), Url::fromUri("http://example.com/drupal-8-$minor_version-1$extra_version.tar.gz")), 'Link to download appears.');
@@ -139,6 +143,7 @@ class UpdateCoreTest extends UpdateTestBase {
           $this->standardTests();
           $this->drupalGet('admin/reports/updates');
           $this->clickLink(t('Check manually'));
+          $this->checkForMetaRefresh();
           $this->assertNoText(t('Security update required!'));
           $this->assertRaw(\Drupal::l('9.0.0', Url::fromUri("http://example.com/drupal-9-0-0-release")), 'Link to release appears.');
           $this->assertRaw(\Drupal::l(t('Download'), Url::fromUri("http://example.com/drupal-9-0-0.tar.gz")), 'Link to download appears.');
@@ -226,6 +231,7 @@ class UpdateCoreTest extends UpdateTestBase {
 
     $this->drupalGet('admin/reports/updates');
     $this->clickLink(t('Check manually'));
+    $this->checkForMetaRefresh();
     $this->assertText(t('Checked available update data for one project.'));
     $this->drupalGet('admin/modules');
     $this->assertNoText(t('There are updates available for your version of Drupal.'));
@@ -247,6 +253,7 @@ class UpdateCoreTest extends UpdateTestBase {
 
     $this->drupalGet('admin/reports/updates');
     $this->clickLink(t('Check manually'));
+    $this->checkForMetaRefresh();
     $this->assertText(t('Checked available update data for one project.'));
     $this->drupalGet('admin/modules');
     $this->assertText(t('There are updates available for your version of Drupal.'));
@@ -268,6 +275,7 @@ class UpdateCoreTest extends UpdateTestBase {
 
     $this->drupalGet('admin/reports/updates');
     $this->clickLink(t('Check manually'));
+    $this->checkForMetaRefresh();
     $this->assertText(t('Checked available update data for one project.'));
     $this->drupalGet('admin/modules');
     $this->assertNoText(t('There are updates available for your version of Drupal.'));
diff --git a/core/modules/update/src/Tests/UpdateDeleteFileIfStaleTest.php b/core/modules/update/tests/src/Functional/UpdateDeleteFileIfStaleTest.php
similarity index 96%
rename from core/modules/update/src/Tests/UpdateDeleteFileIfStaleTest.php
rename to core/modules/update/tests/src/Functional/UpdateDeleteFileIfStaleTest.php
index 99499d77c26..601a6cc2ff0 100644
--- a/core/modules/update/src/Tests/UpdateDeleteFileIfStaleTest.php
+++ b/core/modules/update/tests/src/Functional/UpdateDeleteFileIfStaleTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\update\Tests;
+namespace Drupal\Tests\update\Functional;
 
 /**
  * Tests the update_delete_file_if_stale() function.
diff --git a/core/modules/update/tests/src/Functional/UpdateTestBase.php b/core/modules/update/tests/src/Functional/UpdateTestBase.php
new file mode 100644
index 00000000000..a4d07d0b682
--- /dev/null
+++ b/core/modules/update/tests/src/Functional/UpdateTestBase.php
@@ -0,0 +1,84 @@
+<?php
+
+namespace Drupal\Tests\update\Functional;
+
+use Drupal\Core\DrupalKernel;
+use Drupal\Core\Url;
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Defines some shared functions used by all update tests.
+ *
+ * The overarching methodology of these tests is we need to compare a given
+ * state of installed modules and themes (e.g., version, project grouping,
+ * timestamps, etc) against a current state of what the release history XML
+ * files we fetch say is available. We have dummy XML files (in the
+ * core/modules/update/tests directory) that describe various scenarios of
+ * what's available for different test projects, and we have dummy .info file
+ * data (specified via hook_system_info_alter() in the update_test helper
+ * module) describing what's currently installed. Each test case defines a set
+ * of projects to install, their current state (via the
+ * 'update_test_system_info' variable) and the desired available update data
+ * (via the 'update_test_xml_map' variable), and then performs a series of
+ * assertions that the report matches our expectations given the specific
+ * initial state and availability scenario.
+ */
+abstract class UpdateTestBase extends BrowserTestBase {
+
+  protected function setUp() {
+    parent::setUp();
+
+    // Change the root path which Update Manager uses to install and update
+    // projects to be inside the testing site directory. See
+    // \Drupal\update\UpdateRootFactory::get() for equivalent changes to the
+    // test child site.
+    $request = \Drupal::request();
+    $update_root = $this->container->get('update.root') . '/' . DrupalKernel::findSitePath($request);
+    $this->container->set('update.root', $update_root);
+    \Drupal::setContainer($this->container);
+
+    // Create the directories within the root path within which the Update
+    // Manager will install projects.
+    foreach (drupal_get_updaters() as $updater_info) {
+      $updater = $updater_info['class'];
+      $install_directory = $update_root . '/' . $updater::getRootDirectoryRelativePath();
+      if (!is_dir($install_directory)) {
+        mkdir($install_directory);
+      }
+    }
+  }
+
+  /**
+   * Refreshes the update status based on the desired available update scenario.
+   *
+   * @param $xml_map
+   *   Array that maps project names to availability scenarios to fetch. The key
+   *   '#all' is used if a project-specific mapping is not defined.
+   * @param $url
+   *   (optional) A string containing the URL to fetch update data from.
+   *   Defaults to 'update-test'.
+   *
+   * @see \Drupal\update_test\Controller\UpdateTestController::updateTest()
+   */
+  protected function refreshUpdateStatus($xml_map, $url = 'update-test') {
+    // Tell the Update Manager module to fetch from the URL provided by
+    // update_test module.
+    $this->config('update.settings')->set('fetch.url', Url::fromUri('base:' . $url, ['absolute' => TRUE])->toString())->save();
+    // Save the map for UpdateTestController::updateTest() to use.
+    $this->config('update_test.settings')->set('xml_map', $xml_map)->save();
+    // Manually check the update status.
+    $this->drupalGet('admin/reports/updates');
+    $this->clickLink(t('Check manually'));
+    $this->checkForMetaRefresh();
+  }
+
+  /**
+   * Runs a series of assertions that are applicable to all update statuses.
+   */
+  protected function standardTests() {
+    $this->assertRaw('<h3>' . t('Drupal core') . '</h3>');
+    $this->assertRaw(\Drupal::l(t('Drupal'), Url::fromUri('http://example.com/project/drupal')), 'Link to the Drupal project appears.');
+    $this->assertNoText(t('No available releases found'));
+  }
+
+}
diff --git a/core/modules/update/src/Tests/UpdateUploadTest.php b/core/modules/update/tests/src/Functional/UpdateUploadTest.php
similarity index 96%
rename from core/modules/update/src/Tests/UpdateUploadTest.php
rename to core/modules/update/tests/src/Functional/UpdateUploadTest.php
index 80d3f15d29f..60966200629 100644
--- a/core/modules/update/src/Tests/UpdateUploadTest.php
+++ b/core/modules/update/tests/src/Functional/UpdateUploadTest.php
@@ -1,10 +1,11 @@
 <?php
 
-namespace Drupal\update\Tests;
+namespace Drupal\Tests\update\Functional;
 
 use Drupal\Core\Extension\InfoParserDynamic;
 use Drupal\Core\Updater\Updater;
 use Drupal\Core\Url;
+use Drupal\Tests\TestFileCreationTrait;
 
 /**
  * Tests the Update Manager module's upload and extraction functionality.
@@ -13,6 +14,10 @@ use Drupal\Core\Url;
  */
 class UpdateUploadTest extends UpdateTestBase {
 
+  use TestFileCreationTrait {
+    getTestFiles as drupalGetTestFiles;
+  }
+
   /**
    * Modules to enable.
    *
@@ -50,7 +55,7 @@ class UpdateUploadTest extends UpdateTestBase {
     // Check to ensure an existing module can't be reinstalled. Also checks that
     // the archive was extracted since we can't know if the module is already
     // installed until after extraction.
-    $validArchiveFile = __DIR__ . '/../../tests/aaa_update_test.tar.gz';
+    $validArchiveFile = __DIR__ . '/../../aaa_update_test.tar.gz';
     $edit = [
       'files[project_upload]' => $validArchiveFile,
     ];
@@ -63,7 +68,7 @@ class UpdateUploadTest extends UpdateTestBase {
     $moduleUpdater = $updaters['module']['class'];
     $installedInfoFilePath = $this->container->get('update.root') . '/' . $moduleUpdater::getRootDirectoryRelativePath() . '/update_test_new_module/update_test_new_module.info.yml';
     $this->assertFalse(file_exists($installedInfoFilePath), 'The new module does not exist in the filesystem before it is installed with the Update Manager.');
-    $validArchiveFile = __DIR__ . '/../../tests/update_test_new_module/8.x-1.0/update_test_new_module.tar.gz';
+    $validArchiveFile = __DIR__ . '/../../update_test_new_module/8.x-1.0/update_test_new_module.tar.gz';
     $edit = [
       'files[project_upload]' => $validArchiveFile,
     ];