diff --git a/core/modules/simpletest/simpletest.module b/core/modules/simpletest/simpletest.module
index 34b9596..f5b85a5 100644
--- a/core/modules/simpletest/simpletest.module
+++ b/core/modules/simpletest/simpletest.module
@@ -493,8 +493,6 @@ function simpletest_log_read($test_id, $database_prefix, $test_class) {
  *   (optional) The name of an extension to limit discovery to; e.g., 'node'.
  * @param string[] $types
  *   An array of included test types.
- * @param string[] $exclude_types
- *   (optional) An array of excluded test types.
  *
  * @return array[]
  *   An array of tests keyed with the groups, and then keyed by test classes.
@@ -509,8 +507,8 @@ function simpletest_log_read($test_id, $database_prefix, $test_class) {
  *     );
  *   @endcode
  */
-function simpletest_test_get_all($extension = NULL, array $types = [], array $exclude_types = []) {
-  return \Drupal::service('test_discovery')->getTestClasses($extension, $types, $exclude_types);
+function simpletest_test_get_all($extension = NULL, array $types = []) {
+  return \Drupal::service('test_discovery')->getTestClasses($extension, $types);
 }
 
 /**
diff --git a/core/modules/simpletest/src/TestDiscovery.php b/core/modules/simpletest/src/TestDiscovery.php
index 056e84d..e906ac9 100644
--- a/core/modules/simpletest/src/TestDiscovery.php
+++ b/core/modules/simpletest/src/TestDiscovery.php
@@ -105,6 +105,7 @@ public function registerTestNamespaces() {
     $this->testNamespaces['Drupal\\Tests\\'] = [$this->root . '/core/tests/Drupal/Tests'];
     $this->testNamespaces['Drupal\\KernelTests\\'] = [$this->root . '/core/tests/Drupal/KernelTests'];
     $this->testNamespaces['Drupal\\FunctionalTests\\'] = [$this->root . '/core/tests/Drupal/FunctionalTests'];
+    $this->testNamespaces['Drupal\\FunctionalJavascriptTests\\'] = [$this->root . '/core/tests/Drupal/FunctionalJavascriptTests'];
 
     $this->availableExtensions = array();
     foreach ($this->getExtensions() as $name => $extension) {
@@ -139,8 +140,6 @@ public function registerTestNamespaces() {
    *   (optional) The name of an extension to limit discovery to; e.g., 'node'.
    * @param string[] $types
    *   An array of included test types.
-   * @param string[] $exclude_types
-   *   (optional) An array of excluded test types.
    *
    * @return array An array of tests keyed by the first
    * @code
@@ -156,7 +155,7 @@ public function registerTestNamespaces() {
    * @todo Remove singular grouping; retain list of groups in 'group' key.
    * @see https://www.drupal.org/node/2296615
    */
-  public function getTestClasses($extension = NULL, array $types = [], array $exclude_types = []) {
+  public function getTestClasses($extension = NULL, array $types = []) {
     $reader = new SimpleAnnotationReader();
     $reader->addNamespace('Drupal\\simpletest\\Annotation');
 
@@ -224,11 +223,6 @@ public function getTestClasses($extension = NULL, array $types = [], array $excl
         return !(is_array($element) && isset($element['type']) && !in_array($element['type'], $types));
       });
     }
-    if ($exclude_types) {
-      $list = NestedArray::filter($list, function ($element) use ($exclude_types) {
-        return !(is_array($element) && isset($element['type']) && in_array($element['type'], $exclude_types));
-      });
-    }
 
     return $list;
   }
diff --git a/core/modules/simpletest/tests/src/Unit/TestInfoParsingTest.php b/core/modules/simpletest/tests/src/Unit/TestInfoParsingTest.php
index 8746f42..21dfad3 100644
--- a/core/modules/simpletest/tests/src/Unit/TestInfoParsingTest.php
+++ b/core/modules/simpletest/tests/src/Unit/TestInfoParsingTest.php
@@ -337,43 +337,7 @@ public function testGetTestClasses() {
   /**
    * @covers ::getTestClasses
    */
-  public function testGetTestClassesWithExcludedTypes() {
-    $this->setupVfsWithTestClasses();
-    $class_loader = $this->prophesize(ClassLoader::class);
-    $module_handler = $this->prophesize(ModuleHandlerInterface::class);
-
-    $test_discovery = new TestTestDiscovery('vfs://drupal', $class_loader->reveal(), $module_handler->reveal());
-
-    $extensions = [
-      'test_module' => new Extension('vfs://drupal', 'module', 'modules/test_module/test_module.info.yml'),
-    ];
-    $test_discovery->setExtensions($extensions);
-    $result = $test_discovery->getTestClasses(NULL, [], ['PHPUnit-Kernel']);
-    $this->assertCount(2, $result);
-    $this->assertEquals([
-      'example' => [
-        'Drupal\Tests\test_module\Functional\FunctionalExampleTest' => [
-          'name' => 'Drupal\Tests\test_module\Functional\FunctionalExampleTest',
-          'description' => 'Test description',
-          'group' => 'example',
-          'type' => 'PHPUnit-Functional'
-        ],
-      ],
-      'example2' => [
-        'Drupal\Tests\test_module\Functional\FunctionalExampleTest2' => [
-          'name' => 'Drupal\Tests\test_module\Functional\FunctionalExampleTest2',
-          'description' => 'Test description',
-          'group' => 'example2',
-          'type' => 'PHPUnit-Functional'
-        ],
-      ],
-    ], $result);
-  }
-
-  /**
-   * @covers ::getTestClasses
-   */
-  public function testGetTestClassesWithIncludedTypes() {
+  public function testGetTestClassesWithSelectedTypes() {
     $this->setupVfsWithTestClasses();
     $class_loader = $this->prophesize(ClassLoader::class);
     $module_handler = $this->prophesize(ModuleHandlerInterface::class);
diff --git a/core/scripts/run-tests.sh b/core/scripts/run-tests.sh
index dd46347..db52e6e 100755
--- a/core/scripts/run-tests.sh
+++ b/core/scripts/run-tests.sh
@@ -208,10 +208,10 @@ function simpletest_script_help() {
               Specify the path and the extension
               (i.e. 'core/modules/user/user.test').
 
-  --exclude-types
+  --types
 
-              Runs all tests, but excluding a certain type. Together with --all,
-              its for example to exclude javascript tests from being executed.
+              Runs just tests from the specified test type, for example
+              run-tests.sh --all --types=
 
   --directory Run all tests found within the specified file directory.
 
@@ -298,7 +298,6 @@ function simpletest_script_parse_args() {
     'class' => FALSE,
     'file' => FALSE,
     'types' => [],
-    'exclude-types' => [],
     'directory' => NULL,
     'color' => FALSE,
     'verbose' => FALSE,
@@ -905,7 +904,7 @@ function simpletest_script_get_test_list() {
   $test_list = array();
   if ($args['all'] || $args['module']) {
     try {
-      $groups = simpletest_test_get_all($args['module'], $args['types'], $args['exclude-types']);
+      $groups = simpletest_test_get_all($args['module'], $args['types']);
     }
     catch (Exception $e) {
       echo (string) $e;
@@ -927,7 +926,7 @@ function simpletest_script_get_test_list() {
         }
         else {
           try {
-            $groups = simpletest_test_get_all();
+            $groups = simpletest_test_get_all(NULL, $args['types']);
           }
           catch (Exception $e) {
             echo (string) $e;
@@ -1028,7 +1027,7 @@ function simpletest_script_get_test_list() {
     }
     else {
       try {
-        $groups = simpletest_test_get_all();
+        $groups = simpletest_test_get_all(NULL, $args['types']);
       }
       catch (Exception $e) {
         echo (string) $e;