diff --git a/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php b/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php
index 0457458..c7f28f7 100644
--- a/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php
+++ b/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php
@@ -99,14 +99,11 @@ class ExtensionDiscovery {
    * @param string $type
    *   The extension type to search for. One of 'profile', 'module', 'theme', or
    *   'theme_engine'.
-   * @param bool $include_tests
-   *   (optional) Whether to explicitly include or exclude test extensions. By
-   *   default, test extensions are only discovered when in a test environment.
    *
    * @return \Drupal\Core\Extension\Extension[]
    *   An associative array of Extension objects, keyed by extension name.
    */
-  public function scan($type, $include_tests = NULL) {
+  public function scan($type) {
     // Determine the installation profile directories to scan for extensions,
     // unless explicit profile directories have been set.
     if (!isset($this->profileDirectories)) {
@@ -138,23 +135,11 @@ public function scan($type, $include_tests = NULL) {
     // Search the site-specific directory.
     $searchdirs[static::ORIGIN_SITE] = conf_path();
 
-    // Unless an explicit value has been passed, manually check whether we are
-    // in a test environment, in which case test extensions must be included.
-    // Test extensions can also be included for debugging purposes by setting a
-    // variable in settings.php.
-    if (!isset($include_tests)) {
-      $include_tests = drupal_valid_test_ua() || Settings::get('extension_discovery_scan_tests');
-    }
-
     $files = array();
     foreach ($searchdirs as $dir) {
       // Discover all extensions in the directory, unless we did already.
-      if (!isset(static::$files[$dir][$include_tests])) {
-        static::$files[$dir][$include_tests] = $this->scanDirectory($dir, $include_tests);
-      }
-      // Only return extensions of the requested type.
-      if (isset(static::$files[$dir][$include_tests][$type])) {
-        $files += static::$files[$dir][$include_tests][$type];
+      if (!isset(static::$files[$dir])) {
+        static::$files[$dir] = $this->scanDirectory($dir);
       }
     }
 
@@ -286,9 +271,6 @@ protected function process(array $all_files) {
    *
    * @param string $dir
    *   A relative base directory path to scan, without trailing slash.
-   * @param bool $include_tests
-   *   Whether to include test extensions. If FALSE, all 'tests' directories are
-   *   excluded in the search.
    *
    * @return array
    *   An associative array whose keys are extension type names and whose values
@@ -297,7 +279,7 @@ protected function process(array $all_files) {
    *
    * @see \Drupal\Core\Extension\Discovery\RecursiveExtensionFilterIterator
    */
-  protected function scanDirectory($dir, $include_tests) {
+  protected function scanDirectory($dir) {
     $files = array();
 
     // In order to scan top-level directories, absolute directory paths have to
@@ -321,16 +303,9 @@ protected function scanDirectory($dir, $include_tests) {
     $flags |= \FilesystemIterator::CURRENT_AS_SELF;
     $directory_iterator = new \RecursiveDirectoryIterator($absolute_dir, $flags);
 
-    // Filter the recursive scan to discover extensions only.
-    // Important: Without a RecursiveFilterIterator, RecursiveDirectoryIterator
-    // would recurse into the entire filesystem directory tree without any kind
-    // of limitations.
-    $filter = new RecursiveExtensionFilterIterator($directory_iterator);
-    $filter->acceptTests($include_tests);
-
     // The actual recursive filesystem scan is only invoked by instantiating the
     // RecursiveIteratorIterator.
-    $iterator = new \RecursiveIteratorIterator($filter,
+    $iterator = new \RecursiveIteratorIterator($directory_iterator,
       \RecursiveIteratorIterator::LEAVES_ONLY,
       // Suppress filesystem errors in case a directory cannot be accessed.
       \RecursiveIteratorIterator::CATCH_GET_CHILD
diff --git a/core/modules/action/tests/action_bulk_test/action_bulk_test.info.yml b/core/modules/action/tests/action_bulk_test/action_bulk_test.info.yml
index 296a33a..f9e78fa 100644
--- a/core/modules/action/tests/action_bulk_test/action_bulk_test.info.yml
+++ b/core/modules/action/tests/action_bulk_test/action_bulk_test.info.yml
@@ -4,6 +4,7 @@ description: 'Support module for action bulk form testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
 dependencies:
   - action
   - views
diff --git a/core/modules/aggregator/tests/modules/aggregator_test/aggregator_test.info.yml b/core/modules/aggregator/tests/modules/aggregator_test/aggregator_test.info.yml
index 3d3d0e9..835d3ed 100644
--- a/core/modules/aggregator/tests/modules/aggregator_test/aggregator_test.info.yml
+++ b/core/modules/aggregator/tests/modules/aggregator_test/aggregator_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for aggregator related testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/aggregator/tests/modules/aggregator_test_views/aggregator_test_views.info.yml b/core/modules/aggregator/tests/modules/aggregator_test_views/aggregator_test_views.info.yml
index 58da126..1d99987 100644
--- a/core/modules/aggregator/tests/modules/aggregator_test_views/aggregator_test_views.info.yml
+++ b/core/modules/aggregator/tests/modules/aggregator_test_views/aggregator_test_views.info.yml
@@ -7,3 +7,4 @@ core: 8.x
 dependencies:
   - aggregator
   - views
+hidden: true
diff --git a/core/modules/block/custom_block/tests/modules/custom_block_test/custom_block_test.info.yml b/core/modules/block/custom_block/tests/modules/custom_block_test/custom_block_test.info.yml
index 747efa4..d0cf40c 100644
--- a/core/modules/block/custom_block/tests/modules/custom_block_test/custom_block_test.info.yml
+++ b/core/modules/block/custom_block/tests/modules/custom_block_test/custom_block_test.info.yml
@@ -4,3 +4,4 @@ description: "Support module for custom block related testing."
 package: Testing
 version: VERSION
 core: 8.x
+hidden: TRUE
diff --git a/core/modules/block/tests/modules/block_test/block_test.info.yml b/core/modules/block/tests/modules/block_test/block_test.info.yml
index 9a8895f..d6e4137 100644
--- a/core/modules/block/tests/modules/block_test/block_test.info.yml
+++ b/core/modules/block/tests/modules/block_test/block_test.info.yml
@@ -4,3 +4,4 @@ description: 'Provides test blocks.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/block/tests/modules/block_test/themes/block_test_specialchars_theme/block_test_specialchars_theme.info.yml b/core/modules/block/tests/modules/block_test/themes/block_test_specialchars_theme/block_test_specialchars_theme.info.yml
index 607451f..5b4689e 100644
--- a/core/modules/block/tests/modules/block_test/themes/block_test_specialchars_theme/block_test_specialchars_theme.info.yml
+++ b/core/modules/block/tests/modules/block_test/themes/block_test_specialchars_theme/block_test_specialchars_theme.info.yml
@@ -2,6 +2,7 @@ name: '<"Cat" & ''Mouse''>'
 type: theme
 description: 'Theme for testing special characters in block admin.'
 core: 8.x
+hidden: true
 regions:
   content: Content
   help: Help
diff --git a/core/modules/block/tests/modules/block_test/themes/block_test_theme/block_test_theme.info.yml b/core/modules/block/tests/modules/block_test/themes/block_test_theme/block_test_theme.info.yml
index 96c7650..63fd5b0 100644
--- a/core/modules/block/tests/modules/block_test/themes/block_test_theme/block_test_theme.info.yml
+++ b/core/modules/block/tests/modules/block_test/themes/block_test_theme/block_test_theme.info.yml
@@ -3,6 +3,7 @@ type: theme
 description: 'Theme for testing the block system'
 version: VERSION
 core: 8.x
+hidden: true
 regions:
   sidebar_first: 'Left sidebar'
   sidebar_second: 'Right sidebar'
diff --git a/core/modules/block/tests/modules/block_test_views/block_test_views.info.yml b/core/modules/block/tests/modules/block_test_views/block_test_views.info.yml
index f7a32c0..aad655e 100644
--- a/core/modules/block/tests/modules/block_test_views/block_test_views.info.yml
+++ b/core/modules/block/tests/modules/block_test_views/block_test_views.info.yml
@@ -3,6 +3,7 @@ type: module
 description: 'Provides a view and block to test block displays in views.'
 package: Core
 version: VERSION
+hidden: TRUE
 core: 8.x
 dependencies:
   - block
diff --git a/core/modules/breakpoint/tests/themes/breakpoint_test_theme/breakpoint_test_theme.info.yml b/core/modules/breakpoint/tests/themes/breakpoint_test_theme/breakpoint_test_theme.info.yml
index 779f997..0fa9096 100644
--- a/core/modules/breakpoint/tests/themes/breakpoint_test_theme/breakpoint_test_theme.info.yml
+++ b/core/modules/breakpoint/tests/themes/breakpoint_test_theme/breakpoint_test_theme.info.yml
@@ -4,3 +4,4 @@ description: 'Test theme for breakpoint.'
 version: VERSION
 core: 8.x
 'base theme': bartik
+hidden: true
diff --git a/core/modules/ckeditor/tests/modules/ckeditor_test.info.yml b/core/modules/ckeditor/tests/modules/ckeditor_test.info.yml
index d7d5450..8aad460 100644
--- a/core/modules/ckeditor/tests/modules/ckeditor_test.info.yml
+++ b/core/modules/ckeditor/tests/modules/ckeditor_test.info.yml
@@ -4,3 +4,4 @@ description: Support module for the CKEditor module tests.
 core: 8.x
 package: Testing
 version: VERSION
+hidden: TRUE
diff --git a/core/modules/color/tests/modules/color_test/color_test.info.yml b/core/modules/color/tests/modules/color_test/color_test.info.yml
index 05d954f..7b31bef 100644
--- a/core/modules/color/tests/modules/color_test/color_test.info.yml
+++ b/core/modules/color/tests/modules/color_test/color_test.info.yml
@@ -4,3 +4,4 @@ description: 'Provides test helpers for color module.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/color/tests/modules/color_test/themes/color_test_theme/color_test_theme.info.yml b/core/modules/color/tests/modules/color_test/themes/color_test_theme/color_test_theme.info.yml
index 01f8ffe..3ebd18e 100644
--- a/core/modules/color/tests/modules/color_test/themes/color_test_theme/color_test_theme.info.yml
+++ b/core/modules/color/tests/modules/color_test/themes/color_test_theme/color_test_theme.info.yml
@@ -3,3 +3,4 @@ type: theme
 description: 'Theme for testing the color module'
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/comment/tests/modules/comment_test/comment_test.info.yml b/core/modules/comment/tests/modules/comment_test/comment_test.info.yml
index 712037f..bde96fd 100644
--- a/core/modules/comment/tests/modules/comment_test/comment_test.info.yml
+++ b/core/modules/comment/tests/modules/comment_test/comment_test.info.yml
@@ -4,5 +4,6 @@ description: 'Support module for Comment module testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
 dependencies:
   - comment
diff --git a/core/modules/comment/tests/modules/comment_test_views/comment_test_views.info.yml b/core/modules/comment/tests/modules/comment_test_views/comment_test_views.info.yml
index dfce66d..c9703dc 100644
--- a/core/modules/comment/tests/modules/comment_test_views/comment_test_views.info.yml
+++ b/core/modules/comment/tests/modules/comment_test_views/comment_test_views.info.yml
@@ -7,3 +7,4 @@ core: 8.x
 dependencies:
   - comment
   - views
+hidden: true
diff --git a/core/modules/config/tests/config_events_test/config_events_test.info.yml b/core/modules/config/tests/config_events_test/config_events_test.info.yml
index 95c6799..6cb7504 100644
--- a/core/modules/config/tests/config_events_test/config_events_test.info.yml
+++ b/core/modules/config/tests/config_events_test/config_events_test.info.yml
@@ -3,3 +3,4 @@ type: module
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/config/tests/config_import_test/config_import_test.info.yml b/core/modules/config/tests/config_import_test/config_import_test.info.yml
index 01d2d1d..87cdd02 100644
--- a/core/modules/config/tests/config_import_test/config_import_test.info.yml
+++ b/core/modules/config/tests/config_import_test/config_import_test.info.yml
@@ -3,3 +3,4 @@ type: module
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/config/tests/config_integration_test/config_integration_test.info.yml b/core/modules/config/tests/config_integration_test/config_integration_test.info.yml
index 2c4caa1..dabbd7f 100644
--- a/core/modules/config/tests/config_integration_test/config_integration_test.info.yml
+++ b/core/modules/config/tests/config_integration_test/config_integration_test.info.yml
@@ -3,5 +3,6 @@ type: module
 package: 'Testing'
 version: VERSION
 core: 8.x
+hidden: TRUE
 dependencies:
   - config_test
diff --git a/core/modules/config/tests/config_other_module_config/config_other_module_config.info.yml b/core/modules/config/tests/config_other_module_config/config_other_module_config.info.yml
index 0c332c2..0f78017 100644
--- a/core/modules/config/tests/config_other_module_config/config_other_module_config.info.yml
+++ b/core/modules/config/tests/config_other_module_config/config_other_module_config.info.yml
@@ -3,3 +3,4 @@ type: module
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/config/tests/config_override/config_override.info.yml b/core/modules/config/tests/config_override/config_override.info.yml
index f1f1109..1ccb50b 100644
--- a/core/modules/config/tests/config_override/config_override.info.yml
+++ b/core/modules/config/tests/config_override/config_override.info.yml
@@ -3,3 +3,4 @@ type: module
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/config/tests/config_override_test/config_override_test.yml b/core/modules/config/tests/config_override_test/config_override_test.yml
index f1f1109..1ccb50b 100644
--- a/core/modules/config/tests/config_override_test/config_override_test.yml
+++ b/core/modules/config/tests/config_override_test/config_override_test.yml
@@ -3,3 +3,4 @@ type: module
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/config/tests/config_test/config_test.info.yml b/core/modules/config/tests/config_test/config_test.info.yml
index a4d7b0c..0ce2c40 100644
--- a/core/modules/config/tests/config_test/config_test.info.yml
+++ b/core/modules/config/tests/config_test/config_test.info.yml
@@ -3,3 +3,4 @@ type: module
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/config/tests/config_test_invalid_name/install b/core/modules/config/tests/config_test_invalid_name/install
index 91ed0ae..8bf18bd 100644
--- a/core/modules/config/tests/config_test_invalid_name/install
+++ b/core/modules/config/tests/config_test_invalid_name/install
@@ -3,3 +3,4 @@ type: module
 package: Core
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.info.yml b/core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.info.yml
index d9308c3..47e5f1f 100644
--- a/core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.info.yml
+++ b/core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.info.yml
@@ -4,5 +4,6 @@ type: module
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
 dependencies:
   - config_test
diff --git a/core/modules/config_translation/tests/themes/config_translation_test_theme/config_translation_test_theme.info.yml b/core/modules/config_translation/tests/themes/config_translation_test_theme/config_translation_test_theme.info.yml
index f46d8a0..3b4d655 100644
--- a/core/modules/config_translation/tests/themes/config_translation_test_theme/config_translation_test_theme.info.yml
+++ b/core/modules/config_translation/tests/themes/config_translation_test_theme/config_translation_test_theme.info.yml
@@ -3,3 +3,4 @@ type: theme
 description: 'Theme for testing the configuration translation mapper system'
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/contact/tests/modules/contact_test_views/contact_test_views.info.yml b/core/modules/contact/tests/modules/contact_test_views/contact_test_views.info.yml
index b30ad41..eb3b5e3 100644
--- a/core/modules/contact/tests/modules/contact_test_views/contact_test_views.info.yml
+++ b/core/modules/contact/tests/modules/contact_test_views/contact_test_views.info.yml
@@ -8,3 +8,4 @@ dependencies:
   - contact
   - views
   - user
+hidden: true
diff --git a/core/modules/content_translation/tests/modules/content_translation_test_views/content_translation_test_views.info.yml b/core/modules/content_translation/tests/modules/content_translation_test_views/content_translation_test_views.info.yml
index 0e6574e..9e261db 100644
--- a/core/modules/content_translation/tests/modules/content_translation_test_views/content_translation_test_views.info.yml
+++ b/core/modules/content_translation/tests/modules/content_translation_test_views/content_translation_test_views.info.yml
@@ -7,3 +7,4 @@ core: 8.x
 dependencies:
   - content_translation
   - views
+hidden: true
diff --git a/core/modules/dblog/tests/modules/dblog_test_views/dblog_test_views.info.yml b/core/modules/dblog/tests/modules/dblog_test_views/dblog_test_views.info.yml
index e020973..08e6aa3 100644
--- a/core/modules/dblog/tests/modules/dblog_test_views/dblog_test_views.info.yml
+++ b/core/modules/dblog/tests/modules/dblog_test_views/dblog_test_views.info.yml
@@ -7,3 +7,4 @@ core: 8.x
 dependencies:
   - dblog
   - views
+hidden: TRUE
diff --git a/core/modules/editor/tests/modules/editor_test.info.yml b/core/modules/editor/tests/modules/editor_test.info.yml
index 40b6ff0..102ee02 100644
--- a/core/modules/editor/tests/modules/editor_test.info.yml
+++ b/core/modules/editor/tests/modules/editor_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for the Text Editor module tests.'
 core: 8.x
 package: Testing
 version: VERSION
+hidden: true
diff --git a/core/modules/entity_reference/tests/modules/entity_reference_test/entity_reference_test.info.yml b/core/modules/entity_reference/tests/modules/entity_reference_test/entity_reference_test.info.yml
index 67a5f48..a2460d1 100644
--- a/core/modules/entity_reference/tests/modules/entity_reference_test/entity_reference_test.info.yml
+++ b/core/modules/entity_reference/tests/modules/entity_reference_test/entity_reference_test.info.yml
@@ -4,5 +4,6 @@ description: "Support module for the Entity Reference tests."
 core: 8.x
 package: Testing
 version: VERSION
+hidden: TRUE
 dependencies:
   - entity_reference
diff --git a/core/modules/field/tests/modules/field_test_config/field_test_config.info.yml b/core/modules/field/tests/modules/field_test_config/field_test_config.info.yml
index e3cb0e8..3c8889a 100644
--- a/core/modules/field/tests/modules/field_test_config/field_test_config.info.yml
+++ b/core/modules/field/tests/modules/field_test_config/field_test_config.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for the Field API configuration tests.'
 core: 8.x
 package: Testing
 version: VERSION
+hidden: TRUE
diff --git a/core/modules/field/tests/modules/field_test_views/field_test_views.info.yml b/core/modules/field/tests/modules/field_test_views/field_test_views.info.yml
index 18287b6..2f22790 100644
--- a/core/modules/field/tests/modules/field_test_views/field_test_views.info.yml
+++ b/core/modules/field/tests/modules/field_test_views/field_test_views.info.yml
@@ -6,3 +6,4 @@ version: VERSION
 core: 8.x
 dependencies:
   - views
+hidden: true
diff --git a/core/modules/field_ui/tests/modules/field_ui_test/field_ui_test.info.yml b/core/modules/field_ui/tests/modules/field_ui_test/field_ui_test.info.yml
index b57d967..ff73701 100644
--- a/core/modules/field_ui/tests/modules/field_ui_test/field_ui_test.info.yml
+++ b/core/modules/field_ui/tests/modules/field_ui_test/field_ui_test.info.yml
@@ -4,6 +4,7 @@ description: "Support module for Field UI testing."
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
 
 dependencies:
   - field_ui
diff --git a/core/modules/file/tests/file_module_test/file_module_test.info.yml b/core/modules/file/tests/file_module_test/file_module_test.info.yml
index 097b0a5..2f7e654 100644
--- a/core/modules/file/tests/file_module_test/file_module_test.info.yml
+++ b/core/modules/file/tests/file_module_test/file_module_test.info.yml
@@ -4,3 +4,4 @@ description: 'Provides hooks for testing File module functionality.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/file/tests/file_test/file_test.info.yml b/core/modules/file/tests/file_test/file_test.info.yml
index d5ebfdf..26cb51e 100644
--- a/core/modules/file/tests/file_test/file_test.info.yml
+++ b/core/modules/file/tests/file_test/file_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for file handling tests.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/file/tests/modules/file_test_views/file_test_views.info.yml b/core/modules/file/tests/modules/file_test_views/file_test_views.info.yml
index 41726c7..ff572d6 100644
--- a/core/modules/file/tests/modules/file_test_views/file_test_views.info.yml
+++ b/core/modules/file/tests/modules/file_test_views/file_test_views.info.yml
@@ -7,3 +7,4 @@ core: 8.x
 dependencies:
   - file
   - views
+hidden: true
diff --git a/core/modules/filter/tests/filter_test/filter_test.info.yml b/core/modules/filter/tests/filter_test/filter_test.info.yml
index dcefe8e..4ccefb2 100644
--- a/core/modules/filter/tests/filter_test/filter_test.info.yml
+++ b/core/modules/filter/tests/filter_test/filter_test.info.yml
@@ -4,3 +4,4 @@ description: 'Tests filter hooks and functions.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/forum/tests/modules/forum_test_views/forum_test_views.info.yml b/core/modules/forum/tests/modules/forum_test_views/forum_test_views.info.yml
index f31f030..3b498b2 100644
--- a/core/modules/forum/tests/modules/forum_test_views/forum_test_views.info.yml
+++ b/core/modules/forum/tests/modules/forum_test_views/forum_test_views.info.yml
@@ -7,3 +7,4 @@ core: 8.x
 dependencies:
   - forum
   - views
+hidden: true
diff --git a/core/modules/image/tests/modules/image_module_test/image_module_test.info.yml b/core/modules/image/tests/modules/image_module_test/image_module_test.info.yml
index 9abaf47..d3671f8 100644
--- a/core/modules/image/tests/modules/image_module_test/image_module_test.info.yml
+++ b/core/modules/image/tests/modules/image_module_test/image_module_test.info.yml
@@ -4,3 +4,4 @@ description: 'Provides hook implementations for testing Image module functionali
 package: Core
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/language/tests/language_elements_test/language_elements_test.info.yml b/core/modules/language/tests/language_elements_test/language_elements_test.info.yml
index d8a3da1..254c5f6 100644
--- a/core/modules/language/tests/language_elements_test/language_elements_test.info.yml
+++ b/core/modules/language/tests/language_elements_test/language_elements_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for the language form elements tests.'
 core: 8.x
 package: Testing
 version: VERSION
+hidden: true
diff --git a/core/modules/language/tests/language_test/language_test.info.yml b/core/modules/language/tests/language_test/language_test.info.yml
index 03051cd..8fc0512 100644
--- a/core/modules/language/tests/language_test/language_test.info.yml
+++ b/core/modules/language/tests/language_test/language_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for the language layer tests.'
 core: 8.x
 package: Testing
 version: VERSION
+hidden: true
diff --git a/core/modules/node/tests/modules/node_access_test/node_access_test.info.yml b/core/modules/node/tests/modules/node_access_test/node_access_test.info.yml
index f63cdd6..e2c70c6 100644
--- a/core/modules/node/tests/modules/node_access_test/node_access_test.info.yml
+++ b/core/modules/node/tests/modules/node_access_test/node_access_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for node permission testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/node/tests/modules/node_access_test_language/node_access_test_language.info.yml b/core/modules/node/tests/modules/node_access_test_language/node_access_test_language.info.yml
index 64055ac..3e7ac88 100644
--- a/core/modules/node/tests/modules/node_access_test_language/node_access_test_language.info.yml
+++ b/core/modules/node/tests/modules/node_access_test_language/node_access_test_language.info.yml
@@ -6,3 +6,4 @@ version: VERSION
 core: 8.x
 dependencies:
 - options
+hidden: true
diff --git a/core/modules/node/tests/modules/node_test/node_test.info.yml b/core/modules/node/tests/modules/node_test/node_test.info.yml
index 952456f..9daea15 100644
--- a/core/modules/node/tests/modules/node_test/node_test.info.yml
+++ b/core/modules/node/tests/modules/node_test/node_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for node related testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/node/tests/modules/node_test_config/node_test_config.info.yml b/core/modules/node/tests/modules/node_test_config/node_test_config.info.yml
index c7e7665..948b4a5 100644
--- a/core/modules/node/tests/modules/node_test_config/node_test_config.info.yml
+++ b/core/modules/node/tests/modules/node_test_config/node_test_config.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for node configuration tests.'
 core: 8.x
 package: Testing
 version: VERSION
+hidden: TRUE
diff --git a/core/modules/node/tests/modules/node_test_exception/node_test_exception.info.yml b/core/modules/node/tests/modules/node_test_exception/node_test_exception.info.yml
index fac3fe7..a9ccbfe 100644
--- a/core/modules/node/tests/modules/node_test_exception/node_test_exception.info.yml
+++ b/core/modules/node/tests/modules/node_test_exception/node_test_exception.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for node related exception testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/node/tests/modules/node_test_views/node_test_views.info.yml b/core/modules/node/tests/modules/node_test_views/node_test_views.info.yml
index 194168f..1e0aa16 100644
--- a/core/modules/node/tests/modules/node_test_views/node_test_views.info.yml
+++ b/core/modules/node/tests/modules/node_test_views/node_test_views.info.yml
@@ -7,3 +7,4 @@ core: 8.x
 dependencies:
   - node
   - views
+hidden: true
diff --git a/core/modules/options/tests/options_test.info.yml b/core/modules/options/tests/options_test.info.yml
index add43a4..6826952 100644
--- a/core/modules/options/tests/options_test.info.yml
+++ b/core/modules/options/tests/options_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for the Options module tests.'
 core: 8.x
 package: Testing
 version: VERSION
+hidden: true
diff --git a/core/modules/quickedit/tests/modules/quickedit_test.info.yml b/core/modules/quickedit/tests/modules/quickedit_test.info.yml
index fe21dc5..91c40bd 100644
--- a/core/modules/quickedit/tests/modules/quickedit_test.info.yml
+++ b/core/modules/quickedit/tests/modules/quickedit_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for the Quick Edit module tests.'
 core: 8.x
 package: Testing
 version: VERSION
+hidden: true
diff --git a/core/modules/rdf/tests/rdf_conflicting_namespaces/rdf_conflicting_namespaces.info.yml b/core/modules/rdf/tests/rdf_conflicting_namespaces/rdf_conflicting_namespaces.info.yml
index 65d06db..33a5cd9 100644
--- a/core/modules/rdf/tests/rdf_conflicting_namespaces/rdf_conflicting_namespaces.info.yml
+++ b/core/modules/rdf/tests/rdf_conflicting_namespaces/rdf_conflicting_namespaces.info.yml
@@ -4,5 +4,6 @@ description: 'Test conflicting namespace declaration.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
 dependencies:
   - rdf
diff --git a/core/modules/rdf/tests/rdf_test_namespaces/rdf_test_namespaces.info.yml b/core/modules/rdf/tests/rdf_test_namespaces/rdf_test_namespaces.info.yml
index 84cd974..7ace964 100644
--- a/core/modules/rdf/tests/rdf_test_namespaces/rdf_test_namespaces.info.yml
+++ b/core/modules/rdf/tests/rdf_test_namespaces/rdf_test_namespaces.info.yml
@@ -4,5 +4,6 @@ description: 'Test namespace declaration.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
 dependencies:
   - rdf
diff --git a/core/modules/rest/tests/modules/rest_test_views/rest_test_views.info.yml b/core/modules/rest/tests/modules/rest_test_views/rest_test_views.info.yml
index 662ad1b..debc5e2 100644
--- a/core/modules/rest/tests/modules/rest_test_views/rest_test_views.info.yml
+++ b/core/modules/rest/tests/modules/rest_test_views/rest_test_views.info.yml
@@ -7,3 +7,4 @@ core: 8.x
 dependencies:
   - rest
   - views
+hidden: true
diff --git a/core/modules/search/tests/modules/search_embedded_form/search_embedded_form.info.yml b/core/modules/search/tests/modules/search_embedded_form/search_embedded_form.info.yml
index 0df41aa..9c17197 100644
--- a/core/modules/search/tests/modules/search_embedded_form/search_embedded_form.info.yml
+++ b/core/modules/search/tests/modules/search_embedded_form/search_embedded_form.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for Search module testing of embedded forms.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/search/tests/modules/search_extra_type/search_extra_type.info.yml b/core/modules/search/tests/modules/search_extra_type/search_extra_type.info.yml
index caea321..21a99cf 100644
--- a/core/modules/search/tests/modules/search_extra_type/search_extra_type.info.yml
+++ b/core/modules/search/tests/modules/search_extra_type/search_extra_type.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for Search module testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/search/tests/modules/search_langcode_test/search_langcode_test.info.yml b/core/modules/search/tests/modules/search_langcode_test/search_langcode_test.info.yml
index da34c5f..53d0a4b 100644
--- a/core/modules/search/tests/modules/search_langcode_test/search_langcode_test.info.yml
+++ b/core/modules/search/tests/modules/search_langcode_test/search_langcode_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for search module testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/search/tests/modules/search_query_alter/search_query_alter.info.yml b/core/modules/search/tests/modules/search_query_alter/search_query_alter.info.yml
index 8c6a3d8..870ea25 100644
--- a/core/modules/search/tests/modules/search_query_alter/search_query_alter.info.yml
+++ b/core/modules/search/tests/modules/search_query_alter/search_query_alter.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for Search module testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/serialization/tests/serialization_test/serialization_test.info.yml b/core/modules/serialization/tests/serialization_test/serialization_test.info.yml
index d6c0130..be64412 100644
--- a/core/modules/serialization/tests/serialization_test/serialization_test.info.yml
+++ b/core/modules/serialization/tests/serialization_test/serialization_test.info.yml
@@ -4,3 +4,4 @@ description: "Support module for serialization tests."
 package: Testing
 version: VERSION
 core: 8.x
+hidden: TRUE
diff --git a/core/modules/simpletest/tests/modules/phpunit_test/phpunit_test.info.yml b/core/modules/simpletest/tests/modules/phpunit_test/phpunit_test.info.yml
index e0a4c6e..0fd89ae 100644
--- a/core/modules/simpletest/tests/modules/phpunit_test/phpunit_test.info.yml
+++ b/core/modules/simpletest/tests/modules/phpunit_test/phpunit_test.info.yml
@@ -4,3 +4,4 @@ description: 'Provides dummy classes for use by SimpleTest tests.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: TRUE
diff --git a/core/modules/statistics/tests/modules/statistics_test_views/statistics_test_views.info.yml b/core/modules/statistics/tests/modules/statistics_test_views/statistics_test_views.info.yml
index df9a43a..aff5a56 100644
--- a/core/modules/statistics/tests/modules/statistics_test_views/statistics_test_views.info.yml
+++ b/core/modules/statistics/tests/modules/statistics_test_views/statistics_test_views.info.yml
@@ -4,6 +4,7 @@ description: 'Provides default views for views statistics tests.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: TRUE
 dependencies:
   - statistics
   - views
diff --git a/core/modules/system/tests/modules/action_test/action_test.info.yml b/core/modules/system/tests/modules/action_test/action_test.info.yml
index 7cefe06..c639b27 100644
--- a/core/modules/system/tests/modules/action_test/action_test.info.yml
+++ b/core/modules/system/tests/modules/action_test/action_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for action testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/ajax_forms_test/ajax_forms_test.info.yml b/core/modules/system/tests/modules/ajax_forms_test/ajax_forms_test.info.yml
index ba31a29..054ebff 100644
--- a/core/modules/system/tests/modules/ajax_forms_test/ajax_forms_test.info.yml
+++ b/core/modules/system/tests/modules/ajax_forms_test/ajax_forms_test.info.yml
@@ -4,3 +4,4 @@ description: 'Test for AJAX form calls.'
 core: 8.x
 package: Testing
 version: VERSION
+hidden: true
diff --git a/core/modules/system/tests/modules/ajax_test/ajax_test.info.yml b/core/modules/system/tests/modules/ajax_test/ajax_test.info.yml
index f151748..153eee9 100644
--- a/core/modules/system/tests/modules/ajax_test/ajax_test.info.yml
+++ b/core/modules/system/tests/modules/ajax_test/ajax_test.info.yml
@@ -6,3 +6,4 @@ version: VERSION
 core: 8.x
 dependencies:
   - contact
+hidden: true
diff --git a/core/modules/system/tests/modules/batch_test/batch_test.info.yml b/core/modules/system/tests/modules/batch_test/batch_test.info.yml
index 072017e..b45766d 100644
--- a/core/modules/system/tests/modules/batch_test/batch_test.info.yml
+++ b/core/modules/system/tests/modules/batch_test/batch_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for Batch API tests.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/cache_test/cache_test.info.yml b/core/modules/system/tests/modules/cache_test/cache_test.info.yml
index 329e0d6..b191556 100644
--- a/core/modules/system/tests/modules/cache_test/cache_test.info.yml
+++ b/core/modules/system/tests/modules/cache_test/cache_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for cache system testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/common_test/common_test.info.yml b/core/modules/system/tests/modules/common_test/common_test.info.yml
index 2efb155..1a0bc0c 100644
--- a/core/modules/system/tests/modules/common_test/common_test.info.yml
+++ b/core/modules/system/tests/modules/common_test/common_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for Common tests.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/common_test_cron_helper/common_test_cron_helper.info.yml b/core/modules/system/tests/modules/common_test_cron_helper/common_test_cron_helper.info.yml
index 5d1ab7f..ee46ca8 100644
--- a/core/modules/system/tests/modules/common_test_cron_helper/common_test_cron_helper.info.yml
+++ b/core/modules/system/tests/modules/common_test_cron_helper/common_test_cron_helper.info.yml
@@ -4,3 +4,4 @@ description: 'Helper module for CronRunTestCase::testCronExceptions().'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/condition_test/condition_test.info.yml b/core/modules/system/tests/modules/condition_test/condition_test.info.yml
index b664502..e51633b 100644
--- a/core/modules/system/tests/modules/condition_test/condition_test.info.yml
+++ b/core/modules/system/tests/modules/condition_test/condition_test.info.yml
@@ -4,3 +4,4 @@ description: "Test general form component for condition plugins."
 package: Testing
 version: VERSION
 core: 8.x
+hidden: TRUE
diff --git a/core/modules/system/tests/modules/cron_queue_test/cron_queue_test.info.yml b/core/modules/system/tests/modules/cron_queue_test/cron_queue_test.info.yml
index 014e918..2d6dfa3 100644
--- a/core/modules/system/tests/modules/cron_queue_test/cron_queue_test.info.yml
+++ b/core/modules/system/tests/modules/cron_queue_test/cron_queue_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for the cron queue runner.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/database_test/database_test.info.yml b/core/modules/system/tests/modules/database_test/database_test.info.yml
index 92cea84..914ba1f 100644
--- a/core/modules/system/tests/modules/database_test/database_test.info.yml
+++ b/core/modules/system/tests/modules/database_test/database_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for Database layer tests.'
 core: 8.x
 package: Testing
 version: VERSION
+hidden: true
diff --git a/core/modules/system/tests/modules/drupal_system_listing_compatible_test/drupal_system_listing_compatible_test.info.yml b/core/modules/system/tests/modules/drupal_system_listing_compatible_test/drupal_system_listing_compatible_test.info.yml
index 30bccf7..c419771 100644
--- a/core/modules/system/tests/modules/drupal_system_listing_compatible_test/drupal_system_listing_compatible_test.info.yml
+++ b/core/modules/system/tests/modules/drupal_system_listing_compatible_test/drupal_system_listing_compatible_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for testing the drupal_system_listing function.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/entity_cache_test/entity_cache_test.info.yml b/core/modules/system/tests/modules/entity_cache_test/entity_cache_test.info.yml
index fa4c0fe..e87d44f 100644
--- a/core/modules/system/tests/modules/entity_cache_test/entity_cache_test.info.yml
+++ b/core/modules/system/tests/modules/entity_cache_test/entity_cache_test.info.yml
@@ -6,3 +6,4 @@ version: VERSION
 core: 8.x
 dependencies:
   - entity_cache_test_dependency
+hidden: true
diff --git a/core/modules/system/tests/modules/entity_cache_test_dependency/entity_cache_test_dependency.info.yml b/core/modules/system/tests/modules/entity_cache_test_dependency/entity_cache_test_dependency.info.yml
index 282fcb7..6adf6e3 100644
--- a/core/modules/system/tests/modules/entity_cache_test_dependency/entity_cache_test_dependency.info.yml
+++ b/core/modules/system/tests/modules/entity_cache_test_dependency/entity_cache_test_dependency.info.yml
@@ -4,3 +4,4 @@ description: 'Support dependency module for testing entity cache.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/entity_crud_hook_test/entity_crud_hook_test.info.yml b/core/modules/system/tests/modules/entity_crud_hook_test/entity_crud_hook_test.info.yml
index 7d35503..c46c26b 100644
--- a/core/modules/system/tests/modules/entity_crud_hook_test/entity_crud_hook_test.info.yml
+++ b/core/modules/system/tests/modules/entity_crud_hook_test/entity_crud_hook_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for CRUD hook tests.'
 core: 8.x
 package: Testing
 version: VERSION
+hidden: true
diff --git a/core/modules/system/tests/modules/entity_test/entity_test.info.yml b/core/modules/system/tests/modules/entity_test/entity_test.info.yml
index bd4382e..5bea26a 100644
--- a/core/modules/system/tests/modules/entity_test/entity_test.info.yml
+++ b/core/modules/system/tests/modules/entity_test/entity_test.info.yml
@@ -7,3 +7,4 @@ core: 8.x
 dependencies:
   - field
   - text
+hidden: true
diff --git a/core/modules/system/tests/modules/error_test/error_test.info.yml b/core/modules/system/tests/modules/error_test/error_test.info.yml
index f91c7b3..1b49c4f 100644
--- a/core/modules/system/tests/modules/error_test/error_test.info.yml
+++ b/core/modules/system/tests/modules/error_test/error_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for error and exception testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/form_test/form_test.info.yml b/core/modules/system/tests/modules/form_test/form_test.info.yml
index 39d45ea..3d4280e 100644
--- a/core/modules/system/tests/modules/form_test/form_test.info.yml
+++ b/core/modules/system/tests/modules/form_test/form_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for Form API tests.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/image_test/image_test.info.yml b/core/modules/system/tests/modules/image_test/image_test.info.yml
index 2e54287..e3ed9c5 100644
--- a/core/modules/system/tests/modules/image_test/image_test.info.yml
+++ b/core/modules/system/tests/modules/image_test/image_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for image toolkit tests.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/invalid_module_name_over_the_maximum_allowed_character_length/invalid_module_name_over_the_maximum_allowed_character_length.info.yml b/core/modules/system/tests/modules/invalid_module_name_over_the_maximum_allowed_character_length/invalid_module_name_over_the_maximum_allowed_character_length.info.yml
index db5cdcc..16d9c78 100644
--- a/core/modules/system/tests/modules/invalid_module_name_over_the_maximum_allowed_character_length/invalid_module_name_over_the_maximum_allowed_character_length.info.yml
+++ b/core/modules/system/tests/modules/invalid_module_name_over_the_maximum_allowed_character_length/invalid_module_name_over_the_maximum_allowed_character_length.info.yml
@@ -4,3 +4,4 @@ description: 'Test module with a name over the maximum allowed characters.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: TRUE
diff --git a/core/modules/system/tests/modules/menu_test/menu_test.info.yml b/core/modules/system/tests/modules/menu_test/menu_test.info.yml
index dbba9b8..c927d5f 100644
--- a/core/modules/system/tests/modules/menu_test/menu_test.info.yml
+++ b/core/modules/system/tests/modules/menu_test/menu_test.info.yml
@@ -4,6 +4,7 @@ description: 'Support module for menu hook testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
 dependencies:
   - test_page_test
   - menu_ui
diff --git a/core/modules/system/tests/modules/module_autoload_test/module_autoload_test.info.yml b/core/modules/system/tests/modules/module_autoload_test/module_autoload_test.info.yml
index 1805185..4437ef6 100644
--- a/core/modules/system/tests/modules/module_autoload_test/module_autoload_test.info.yml
+++ b/core/modules/system/tests/modules/module_autoload_test/module_autoload_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for module system tests.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/module_test/module_test.info.yml b/core/modules/system/tests/modules/module_test/module_test.info.yml
index 025525c..390706d 100644
--- a/core/modules/system/tests/modules/module_test/module_test.info.yml
+++ b/core/modules/system/tests/modules/module_test/module_test.info.yml
@@ -4,6 +4,7 @@ description: 'Support module for module system testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
 # Depends on the Node module to test making a module required using
 # hook_system_info_alter() and ensuring that its dependencies also become
 # required.
diff --git a/core/modules/system/tests/modules/paramconverter_test/paramconverter_test.info.yml b/core/modules/system/tests/modules/paramconverter_test/paramconverter_test.info.yml
index 1953d92..4aa2455 100644
--- a/core/modules/system/tests/modules/paramconverter_test/paramconverter_test.info.yml
+++ b/core/modules/system/tests/modules/paramconverter_test/paramconverter_test.info.yml
@@ -4,3 +4,4 @@ description: "Support module for paramconverter testing."
 package: Testing
 version: VERSION
 core: 8.x
+hidden: TRUE
diff --git a/core/modules/system/tests/modules/path_test/path_test.info.yml b/core/modules/system/tests/modules/path_test/path_test.info.yml
index ec7e405..57a5893 100644
--- a/core/modules/system/tests/modules/path_test/path_test.info.yml
+++ b/core/modules/system/tests/modules/path_test/path_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for path hook testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/plugin_test/plugin_test.info.yml b/core/modules/system/tests/modules/plugin_test/plugin_test.info.yml
index 950a1d0..087ce08 100644
--- a/core/modules/system/tests/modules/plugin_test/plugin_test.info.yml
+++ b/core/modules/system/tests/modules/plugin_test/plugin_test.info.yml
@@ -4,3 +4,4 @@ description: 'Test that plugins can provide plugins and provide namespace discov
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/requirements1_test/requirements1_test.info.yml b/core/modules/system/tests/modules/requirements1_test/requirements1_test.info.yml
index 6288bf3..789cf27 100644
--- a/core/modules/system/tests/modules/requirements1_test/requirements1_test.info.yml
+++ b/core/modules/system/tests/modules/requirements1_test/requirements1_test.info.yml
@@ -4,3 +4,4 @@ description: 'Tests that a module is not installed when it fails hook_requiremen
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/requirements2_test/requirements2_test.info.yml b/core/modules/system/tests/modules/requirements2_test/requirements2_test.info.yml
index 670df80..ed093d8 100644
--- a/core/modules/system/tests/modules/requirements2_test/requirements2_test.info.yml
+++ b/core/modules/system/tests/modules/requirements2_test/requirements2_test.info.yml
@@ -7,3 +7,4 @@ dependencies:
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/router_test_directory/router_test.info.yml b/core/modules/system/tests/modules/router_test_directory/router_test.info.yml
index 27a0827..915f0ff 100644
--- a/core/modules/system/tests/modules/router_test_directory/router_test.info.yml
+++ b/core/modules/system/tests/modules/router_test_directory/router_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for routing testing. In a directory that does not m
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/service_provider_test/service_provider_test.info.yml b/core/modules/system/tests/modules/service_provider_test/service_provider_test.info.yml
index ba84020..620c897 100644
--- a/core/modules/system/tests/modules/service_provider_test/service_provider_test.info.yml
+++ b/core/modules/system/tests/modules/service_provider_test/service_provider_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for service provider testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/session_test/session_test.info.yml b/core/modules/system/tests/modules/session_test/session_test.info.yml
index b9abfef..9e80a1c 100644
--- a/core/modules/system/tests/modules/session_test/session_test.info.yml
+++ b/core/modules/system/tests/modules/session_test/session_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for session data testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/system_dependencies_test/system_dependencies_test.info.yml b/core/modules/system/tests/modules/system_dependencies_test/system_dependencies_test.info.yml
index e99d48e..e3ac2dc 100644
--- a/core/modules/system/tests/modules/system_dependencies_test/system_dependencies_test.info.yml
+++ b/core/modules/system/tests/modules/system_dependencies_test/system_dependencies_test.info.yml
@@ -4,5 +4,6 @@ description: 'Support module for testing system dependencies.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
 dependencies:
   - _missing_dependency
diff --git a/core/modules/system/tests/modules/system_incompatible_core_version_dependencies_test/system_incompatible_core_version_dependencies_test.info.yml b/core/modules/system/tests/modules/system_incompatible_core_version_dependencies_test/system_incompatible_core_version_dependencies_test.info.yml
index 148bd3b..4f6a8c0 100644
--- a/core/modules/system/tests/modules/system_incompatible_core_version_dependencies_test/system_incompatible_core_version_dependencies_test.info.yml
+++ b/core/modules/system/tests/modules/system_incompatible_core_version_dependencies_test/system_incompatible_core_version_dependencies_test.info.yml
@@ -4,5 +4,6 @@ description: 'Support module for testing system dependencies.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
 dependencies:
   - system_incompatible_core_version_test
diff --git a/core/modules/system/tests/modules/system_incompatible_core_version_test/system_incompatible_core_version_test.info.yml b/core/modules/system/tests/modules/system_incompatible_core_version_test/system_incompatible_core_version_test.info.yml
index d99300b..47dce2b 100644
--- a/core/modules/system/tests/modules/system_incompatible_core_version_test/system_incompatible_core_version_test.info.yml
+++ b/core/modules/system/tests/modules/system_incompatible_core_version_test/system_incompatible_core_version_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for testing system dependencies.'
 package: Testing
 version: VERSION
 core: 5.x
+hidden: true
diff --git a/core/modules/system/tests/modules/system_incompatible_module_version_dependencies_test/system_incompatible_module_version_dependencies_test.info.yml b/core/modules/system/tests/modules/system_incompatible_module_version_dependencies_test/system_incompatible_module_version_dependencies_test.info.yml
index 55e004b..244235f 100644
--- a/core/modules/system/tests/modules/system_incompatible_module_version_dependencies_test/system_incompatible_module_version_dependencies_test.info.yml
+++ b/core/modules/system/tests/modules/system_incompatible_module_version_dependencies_test/system_incompatible_module_version_dependencies_test.info.yml
@@ -4,5 +4,6 @@ description: 'Support module for testing system dependencies.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
 dependencies:
   - 'system_incompatible_module_version_test (>2.0)'
diff --git a/core/modules/system/tests/modules/system_incompatible_module_version_test/system_incompatible_module_version_test.info.yml b/core/modules/system/tests/modules/system_incompatible_module_version_test/system_incompatible_module_version_test.info.yml
index f0076b1..78c1a90 100644
--- a/core/modules/system/tests/modules/system_incompatible_module_version_test/system_incompatible_module_version_test.info.yml
+++ b/core/modules/system/tests/modules/system_incompatible_module_version_test/system_incompatible_module_version_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for testing system dependencies.'
 package: Testing
 version: '1.0'
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/system_mail_failure_test/system_mail_failure_test.info.yml b/core/modules/system/tests/modules/system_mail_failure_test/system_mail_failure_test.info.yml
index 12ad6e2..3561097 100644
--- a/core/modules/system/tests/modules/system_mail_failure_test/system_mail_failure_test.info.yml
+++ b/core/modules/system/tests/modules/system_mail_failure_test/system_mail_failure_test.info.yml
@@ -4,3 +4,4 @@ description: 'Provides a malfunctioning mail service for testing purposes.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/system_module_test/system_module_test.info.yml b/core/modules/system/tests/modules/system_module_test/system_module_test.info.yml
index 6b787f5..c4403d3 100644
--- a/core/modules/system/tests/modules/system_module_test/system_module_test.info.yml
+++ b/core/modules/system/tests/modules/system_module_test/system_module_test.info.yml
@@ -4,3 +4,4 @@ description: 'Provides hook implementations for testing System module functional
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/system_test/system_test.info.yml b/core/modules/system/tests/modules/system_test/system_test.info.yml
index 7228709..eff3630 100644
--- a/core/modules/system/tests/modules/system_test/system_test.info.yml
+++ b/core/modules/system/tests/modules/system_test/system_test.info.yml
@@ -4,6 +4,7 @@ description: 'Support module for system testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
 configure: system_test.configure
 configure_parameters:
   foo: bar
diff --git a/core/modules/system/tests/modules/test_page_test/test_page_test.info.yml b/core/modules/system/tests/modules/test_page_test/test_page_test.info.yml
index f01c597..053deb2 100644
--- a/core/modules/system/tests/modules/test_page_test/test_page_test.info.yml
+++ b/core/modules/system/tests/modules/test_page_test/test_page_test.info.yml
@@ -4,3 +4,4 @@ description: 'Provides a test page for automated tests.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/theme_page_test/theme_page_test.info.yml b/core/modules/system/tests/modules/theme_page_test/theme_page_test.info.yml
index da50bb1..587e8a1 100644
--- a/core/modules/system/tests/modules/theme_page_test/theme_page_test.info.yml
+++ b/core/modules/system/tests/modules/theme_page_test/theme_page_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for theme system testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/theme_suggestions_test/theme_suggestions_test.info.yml b/core/modules/system/tests/modules/theme_suggestions_test/theme_suggestions_test.info.yml
index fe61d0d..95f429f 100644
--- a/core/modules/system/tests/modules/theme_suggestions_test/theme_suggestions_test.info.yml
+++ b/core/modules/system/tests/modules/theme_suggestions_test/theme_suggestions_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for testing theme suggestions.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/theme_test/theme_test.info.yml b/core/modules/system/tests/modules/theme_test/theme_test.info.yml
index 0fe8c10..863e112 100644
--- a/core/modules/system/tests/modules/theme_test/theme_test.info.yml
+++ b/core/modules/system/tests/modules/theme_test/theme_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for theme system testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/transliterate_test/transliterate_test.info.yml b/core/modules/system/tests/modules/transliterate_test/transliterate_test.info.yml
index 9eeddd5..15a724e 100644
--- a/core/modules/system/tests/modules/transliterate_test/transliterate_test.info.yml
+++ b/core/modules/system/tests/modules/transliterate_test/transliterate_test.info.yml
@@ -4,3 +4,4 @@ description: 'Helper module for Transliteration system tests.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/twig_extension_test/twig_extension_test.info.yml b/core/modules/system/tests/modules/twig_extension_test/twig_extension_test.info.yml
index 5aee1e2..270352f 100644
--- a/core/modules/system/tests/modules/twig_extension_test/twig_extension_test.info.yml
+++ b/core/modules/system/tests/modules/twig_extension_test/twig_extension_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for testing Twig extensions.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/twig_theme_test/modules/twig_namespace_a/twig_namespace_a.info.yml b/core/modules/system/tests/modules/twig_theme_test/modules/twig_namespace_a/twig_namespace_a.info.yml
index 7584b57..d007f21 100644
--- a/core/modules/system/tests/modules/twig_theme_test/modules/twig_namespace_a/twig_namespace_a.info.yml
+++ b/core/modules/system/tests/modules/twig_theme_test/modules/twig_namespace_a/twig_namespace_a.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for Twig namespace testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/twig_theme_test/modules/twig_namespace_b/twig_namespace_b.info.yml b/core/modules/system/tests/modules/twig_theme_test/modules/twig_namespace_b/twig_namespace_b.info.yml
index 7584b57..d007f21 100644
--- a/core/modules/system/tests/modules/twig_theme_test/modules/twig_namespace_b/twig_namespace_b.info.yml
+++ b/core/modules/system/tests/modules/twig_theme_test/modules/twig_namespace_b/twig_namespace_b.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for Twig namespace testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/twig_theme_test/twig_theme_test.info.yml b/core/modules/system/tests/modules/twig_theme_test/twig_theme_test.info.yml
index 7515315..f340341 100644
--- a/core/modules/system/tests/modules/twig_theme_test/twig_theme_test.info.yml
+++ b/core/modules/system/tests/modules/twig_theme_test/twig_theme_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for Twig theme system testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/update_script_test/update_script_test.info.yml b/core/modules/system/tests/modules/update_script_test/update_script_test.info.yml
index b582c1a..cd04f16 100644
--- a/core/modules/system/tests/modules/update_script_test/update_script_test.info.yml
+++ b/core/modules/system/tests/modules/update_script_test/update_script_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for update script testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/update_test_0/update_test_0.info.yml b/core/modules/system/tests/modules/update_test_0/update_test_0.info.yml
index 4162fd0..d9f07cd 100644
--- a/core/modules/system/tests/modules/update_test_0/update_test_0.info.yml
+++ b/core/modules/system/tests/modules/update_test_0/update_test_0.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for update testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/update_test_1/update_test_1.info.yml b/core/modules/system/tests/modules/update_test_1/update_test_1.info.yml
index 5a7e2e1..8ac616f 100644
--- a/core/modules/system/tests/modules/update_test_1/update_test_1.info.yml
+++ b/core/modules/system/tests/modules/update_test_1/update_test_1.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for update testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/update_test_2/update_test_2.info.yml b/core/modules/system/tests/modules/update_test_2/update_test_2.info.yml
index 5a7e2e1..8ac616f 100644
--- a/core/modules/system/tests/modules/update_test_2/update_test_2.info.yml
+++ b/core/modules/system/tests/modules/update_test_2/update_test_2.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for update testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/update_test_3/update_test_3.info.yml b/core/modules/system/tests/modules/update_test_3/update_test_3.info.yml
index 5a7e2e1..8ac616f 100644
--- a/core/modules/system/tests/modules/update_test_3/update_test_3.info.yml
+++ b/core/modules/system/tests/modules/update_test_3/update_test_3.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for update testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/update_test_invalid_hook/update_test_invalid_hook.info.yml b/core/modules/system/tests/modules/update_test_invalid_hook/update_test_invalid_hook.info.yml
index b9aefba..a41ace9 100644
--- a/core/modules/system/tests/modules/update_test_invalid_hook/update_test_invalid_hook.info.yml
+++ b/core/modules/system/tests/modules/update_test_invalid_hook/update_test_invalid_hook.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for update testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/update_test_with_7x/update_test_with_7x.info.yml b/core/modules/system/tests/modules/update_test_with_7x/update_test_with_7x.info.yml
index 2b47a04..3ac4a35 100644
--- a/core/modules/system/tests/modules/update_test_with_7x/update_test_with_7x.info.yml
+++ b/core/modules/system/tests/modules/update_test_with_7x/update_test_with_7x.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for update testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/system/tests/modules/url_alter_test/url_alter_test.info.yml b/core/modules/system/tests/modules/url_alter_test/url_alter_test.info.yml
index 95aba30..699683e 100644
--- a/core/modules/system/tests/modules/url_alter_test/url_alter_test.info.yml
+++ b/core/modules/system/tests/modules/url_alter_test/url_alter_test.info.yml
@@ -4,3 +4,4 @@ description: 'A support module to test altering the inbound and outbound path.'
 core: 8.x
 package: Testing
 version: VERSION
+hidden: true
diff --git a/core/modules/system/tests/themes/test_basetheme/test_basetheme.info.yml b/core/modules/system/tests/themes/test_basetheme/test_basetheme.info.yml
index 2edc823..48c5b2b 100644
--- a/core/modules/system/tests/themes/test_basetheme/test_basetheme.info.yml
+++ b/core/modules/system/tests/themes/test_basetheme/test_basetheme.info.yml
@@ -3,6 +3,7 @@ type: theme
 description: 'Test theme which acts as a base theme for other test subthemes.'
 version: VERSION
 core: 8.x
+hidden: true
 stylesheets:
   all:
     - base-add.css
diff --git a/core/modules/system/tests/themes/test_invalid_basetheme/test_invalid_basetheme.info.yml b/core/modules/system/tests/themes/test_invalid_basetheme/test_invalid_basetheme.info.yml
index f29a4d4..a8d2bfe 100644
--- a/core/modules/system/tests/themes/test_invalid_basetheme/test_invalid_basetheme.info.yml
+++ b/core/modules/system/tests/themes/test_invalid_basetheme/test_invalid_basetheme.info.yml
@@ -4,3 +4,4 @@ description: 'Test theme which has a non-existent base theme.'
 version: VERSION
 core: 8.x
 'base theme': not_real_test_basetheme
+hidden: true
diff --git a/core/modules/system/tests/themes/test_invalid_engine/test_invalid_engine.info.yml b/core/modules/system/tests/themes/test_invalid_engine/test_invalid_engine.info.yml
index 229ede4..3f9ed1e 100644
--- a/core/modules/system/tests/themes/test_invalid_engine/test_invalid_engine.info.yml
+++ b/core/modules/system/tests/themes/test_invalid_engine/test_invalid_engine.info.yml
@@ -3,4 +3,5 @@ type: theme
 description: 'Test theme which has a non-existent theme engine.'
 version: VERSION
 core: 8.x
+hidden: true
 engine: not_real_engine
diff --git a/core/modules/system/tests/themes/test_subtheme/test_subtheme.info.yml b/core/modules/system/tests/themes/test_subtheme/test_subtheme.info.yml
index 6adfee4..6123684 100644
--- a/core/modules/system/tests/themes/test_subtheme/test_subtheme.info.yml
+++ b/core/modules/system/tests/themes/test_subtheme/test_subtheme.info.yml
@@ -4,6 +4,7 @@ description: 'Test theme which uses test_basetheme as the base theme.'
 version: VERSION
 core: 8.x
 'base theme': test_basetheme
+hidden: true
 stylesheets:
   all:
     - css/sub-add.css
diff --git a/core/modules/system/tests/themes/test_theme/test_theme.info.yml b/core/modules/system/tests/themes/test_theme/test_theme.info.yml
index d845875..f41fafc 100644
--- a/core/modules/system/tests/themes/test_theme/test_theme.info.yml
+++ b/core/modules/system/tests/themes/test_theme/test_theme.info.yml
@@ -13,6 +13,7 @@ type: theme
 description: 'Theme for testing the theme system'
 version: VERSION
 core: 8.x
+hidden: true
 stylesheets-remove:
   - system.module.css
 settings:
diff --git a/core/modules/system/tests/themes/test_theme_having_veery_long_name_which_is_too_long/test_theme_having_veery_long_name_which_is_too_long.info.yml b/core/modules/system/tests/themes/test_theme_having_veery_long_name_which_is_too_long/test_theme_having_veery_long_name_which_is_too_long.info.yml
index 46432b4..fa0a207 100644
--- a/core/modules/system/tests/themes/test_theme_having_veery_long_name_which_is_too_long/test_theme_having_veery_long_name_which_is_too_long.info.yml
+++ b/core/modules/system/tests/themes/test_theme_having_veery_long_name_which_is_too_long/test_theme_having_veery_long_name_which_is_too_long.info.yml
@@ -2,3 +2,4 @@ type: theme
 core: 8.x
 name: 'Test theme with a too long name'
 version: VERSION
+hidden: true
diff --git a/core/modules/system/tests/themes/test_theme_phptemplate/test_theme_phptemplate.info.yml b/core/modules/system/tests/themes/test_theme_phptemplate/test_theme_phptemplate.info.yml
index da076b1..e1a876a 100644
--- a/core/modules/system/tests/themes/test_theme_phptemplate/test_theme_phptemplate.info.yml
+++ b/core/modules/system/tests/themes/test_theme_phptemplate/test_theme_phptemplate.info.yml
@@ -4,3 +4,4 @@ description: 'Theme for testing the theme system with the PHPTemplate engine'
 version: VERSION
 core: 8.x
 engine: phptemplate
+hidden: true
diff --git a/core/modules/taxonomy/tests/modules/taxonomy_test_views/taxonomy_test_views.info.yml b/core/modules/taxonomy/tests/modules/taxonomy_test_views/taxonomy_test_views.info.yml
index be87906..864ce98 100644
--- a/core/modules/taxonomy/tests/modules/taxonomy_test_views/taxonomy_test_views.info.yml
+++ b/core/modules/taxonomy/tests/modules/taxonomy_test_views/taxonomy_test_views.info.yml
@@ -7,3 +7,4 @@ core: 8.x
 dependencies:
   - taxonomy
   - views
+hidden: true
diff --git a/core/modules/toolbar/tests/modules/toolbar_test/toolbar_test.info.yml b/core/modules/toolbar/tests/modules/toolbar_test/toolbar_test.info.yml
index 98fc607..961d81e 100644
--- a/core/modules/toolbar/tests/modules/toolbar_test/toolbar_test.info.yml
+++ b/core/modules/toolbar/tests/modules/toolbar_test/toolbar_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for toolbar testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/tour/tests/tour_test/tour_test.info.yml b/core/modules/tour/tests/tour_test/tour_test.info.yml
index e55953a..0617983 100644
--- a/core/modules/tour/tests/tour_test/tour_test.info.yml
+++ b/core/modules/tour/tests/tour_test/tour_test.info.yml
@@ -4,5 +4,6 @@ description: Tests module for tour module.
 package: Core
 version: VERSION
 core: 8.x
+hidden: TRUE
 dependencies:
   - tour
diff --git a/core/modules/tracker/tests/modules/tracker_test_views/tracker_test_views.info.yml b/core/modules/tracker/tests/modules/tracker_test_views/tracker_test_views.info.yml
index 45a64a1..9eb2c61 100644
--- a/core/modules/tracker/tests/modules/tracker_test_views/tracker_test_views.info.yml
+++ b/core/modules/tracker/tests/modules/tracker_test_views/tracker_test_views.info.yml
@@ -7,3 +7,4 @@ core: 8.x
 dependencies:
   - tracker
   - views
+hidden: true
diff --git a/core/modules/update/tests/aaa_update_test/aaa_update_test.info.yml b/core/modules/update/tests/aaa_update_test/aaa_update_test.info.yml
index c424e74..0bfea75 100644
--- a/core/modules/update/tests/aaa_update_test/aaa_update_test.info.yml
+++ b/core/modules/update/tests/aaa_update_test/aaa_update_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for update module testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/update/tests/modules/aaa_update_test/aaa_update_test.info.yml b/core/modules/update/tests/modules/aaa_update_test/aaa_update_test.info.yml
index c424e74..0bfea75 100644
--- a/core/modules/update/tests/modules/aaa_update_test/aaa_update_test.info.yml
+++ b/core/modules/update/tests/modules/aaa_update_test/aaa_update_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for update module testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/update/tests/modules/bbb_update_test/bbb_update_test.info.yml b/core/modules/update/tests/modules/bbb_update_test/bbb_update_test.info.yml
index 0c2226b..25540c3 100644
--- a/core/modules/update/tests/modules/bbb_update_test/bbb_update_test.info.yml
+++ b/core/modules/update/tests/modules/bbb_update_test/bbb_update_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for update module testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/update/tests/modules/ccc_update_test/ccc_update_test.info.yml b/core/modules/update/tests/modules/ccc_update_test/ccc_update_test.info.yml
index 6fcd4ec..919adcd 100644
--- a/core/modules/update/tests/modules/ccc_update_test/ccc_update_test.info.yml
+++ b/core/modules/update/tests/modules/ccc_update_test/ccc_update_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for update module testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/update/tests/modules/update_test/update_test.info.yml b/core/modules/update/tests/modules/update_test/update_test.info.yml
index 053aafc..f6e38a3 100644
--- a/core/modules/update/tests/modules/update_test/update_test.info.yml
+++ b/core/modules/update/tests/modules/update_test/update_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for update module testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/update/tests/themes/update_test_basetheme/update_test_basetheme.info.yml b/core/modules/update/tests/themes/update_test_basetheme/update_test_basetheme.info.yml
index 9162147..cdb01bb 100644
--- a/core/modules/update/tests/themes/update_test_basetheme/update_test_basetheme.info.yml
+++ b/core/modules/update/tests/themes/update_test_basetheme/update_test_basetheme.info.yml
@@ -3,3 +3,4 @@ type: theme
 description: 'Test theme which acts as a base theme for other test subthemes.'
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/update/tests/themes/update_test_subtheme/update_test_subtheme.info.yml b/core/modules/update/tests/themes/update_test_subtheme/update_test_subtheme.info.yml
index 2580fd6..d844542 100644
--- a/core/modules/update/tests/themes/update_test_subtheme/update_test_subtheme.info.yml
+++ b/core/modules/update/tests/themes/update_test_subtheme/update_test_subtheme.info.yml
@@ -4,3 +4,4 @@ description: 'Test theme which uses update_test_basetheme as the base theme.'
 version: VERSION
 core: 8.x
 'base theme': update_test_basetheme
+hidden: true
diff --git a/core/modules/user/tests/modules/user_custom_phpass_params_test/user_custom_phpass_params_test.info.yml b/core/modules/user/tests/modules/user_custom_phpass_params_test/user_custom_phpass_params_test.info.yml
index 68b8ff9..f227a34 100644
--- a/core/modules/user/tests/modules/user_custom_phpass_params_test/user_custom_phpass_params_test.info.yml
+++ b/core/modules/user/tests/modules/user_custom_phpass_params_test/user_custom_phpass_params_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for testing custom phpass password algorithm parame
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/user/tests/modules/user_form_test/user_form_test.info.yml b/core/modules/user/tests/modules/user_form_test/user_form_test.info.yml
index e77ebf2..ceea331 100644
--- a/core/modules/user/tests/modules/user_form_test/user_form_test.info.yml
+++ b/core/modules/user/tests/modules/user_form_test/user_form_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for user form testing.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/modules/user/tests/modules/user_test_views/user_test_views.info.yml b/core/modules/user/tests/modules/user_test_views/user_test_views.info.yml
index 2554769..e13b350 100644
--- a/core/modules/user/tests/modules/user_test_views/user_test_views.info.yml
+++ b/core/modules/user/tests/modules/user_test_views/user_test_views.info.yml
@@ -7,3 +7,4 @@ core: 8.x
 dependencies:
   - user
   - views
+hidden: true
diff --git a/core/modules/views/tests/modules/views_test_config/views_test_config.info.yml b/core/modules/views/tests/modules/views_test_config/views_test_config.info.yml
index 3392573..edbfd9c 100644
--- a/core/modules/views/tests/modules/views_test_config/views_test_config.info.yml
+++ b/core/modules/views/tests/modules/views_test_config/views_test_config.info.yml
@@ -6,3 +6,4 @@ version: VERSION
 core: 8.x
 dependencies:
   - views
+hidden: true
diff --git a/core/modules/views/tests/modules/views_test_data/views_test_data.info.yml b/core/modules/views/tests/modules/views_test_data/views_test_data.info.yml
index 39b72e4..07084c0 100644
--- a/core/modules/views/tests/modules/views_test_data/views_test_data.info.yml
+++ b/core/modules/views/tests/modules/views_test_data/views_test_data.info.yml
@@ -6,3 +6,4 @@ version: VERSION
 core: 8.x
 dependencies:
   - views
+hidden: true
diff --git a/core/modules/xmlrpc/tests/modules/xmlrpc_test/xmlrpc_test.info.yml b/core/modules/xmlrpc/tests/modules/xmlrpc_test/xmlrpc_test.info.yml
index 0359f92..9c0fe2a 100644
--- a/core/modules/xmlrpc/tests/modules/xmlrpc_test/xmlrpc_test.info.yml
+++ b/core/modules/xmlrpc/tests/modules/xmlrpc_test/xmlrpc_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for XML-RPC tests according to the validator1 speci
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true
diff --git a/core/profiles/testing/modules/drupal_system_listing_compatible_test/drupal_system_listing_compatible_test.info.yml b/core/profiles/testing/modules/drupal_system_listing_compatible_test/drupal_system_listing_compatible_test.info.yml
index 30bccf7..c419771 100644
--- a/core/profiles/testing/modules/drupal_system_listing_compatible_test/drupal_system_listing_compatible_test.info.yml
+++ b/core/profiles/testing/modules/drupal_system_listing_compatible_test/drupal_system_listing_compatible_test.info.yml
@@ -4,3 +4,4 @@ description: 'Support module for testing the drupal_system_listing function.'
 package: Testing
 version: VERSION
 core: 8.x
+hidden: true