Update to Drupal 8.2.5. For more information, see https://www.drupal.org/project/drupal/releases/8.2.5

core/modules/system/tests/modules/experimental_module_requirements_test/experimental_module_requirements_test.info.yml

@@ -0,0 +1,6 @@
+name: 'Experimental Requirements Test'
+type: module
+description: 'Module in the experimental package to test hook_requirements() with an experimental module.'
+package: Core (Experimental)
+version: VERSION
+core: 8.x

core/modules/system/tests/modules/experimental_module_requirements_test/experimental_module_requirements_test.install

@@ -0,0 +1,20 @@
+<?php
+
+/**
+ * @file
+ * Experimental Test Requirements module to test hook_requirements().
+ */
+
+/**
+ * Implements hook_requirements().
+ */
+function experimental_module_requirements_test_requirements() {
+  $requirements = [];
+  if (\Drupal::state()->get('experimental_module_requirements_test_requirements', FALSE)) {
+    $requirements['experimental_module_requirements_test_requirements'] = [
+      'severity' => REQUIREMENT_ERROR,
+      'description' => t('The Experimental Test Requirements module can not be installed.'),
+    ];
+  }
+  return $requirements;
+}

core/modules/system/tests/modules/experimental_module_requirements_test/experimental_module_requirements_test.module

@@ -0,0 +1,18 @@
+<?php
+
+/**
+ * @file
+ * Experimental Test Requirements module to test hook_requirements().
+ */
+
+/**
+ * Implements hook_help().
+ */
+function experimental_module_requirements_test_help($route_name) {
+  switch ($route_name) {
+    case 'help.page.experimental_module_requirements_test':
+      // Make the help text conform to core standards. See
+      // \Drupal\system\Tests\Module\InstallUninstallTest::assertHelp().
+      return t('The Experimental Requirements Test module is not done yet. It may eat your data, but you can read the <a href=":url">online documentation for the Experimental Requirements Test module</a>.', [':url' => 'http://www.example.com']);
+  }
+}