diff --git a/core/lib/Drupal/Core/Extension/ModuleHandler.php b/core/lib/Drupal/Core/Extension/ModuleHandler.php
index 7598c8a284..f04eeca72a 100644
--- a/core/lib/Drupal/Core/Extension/ModuleHandler.php
+++ b/core/lib/Drupal/Core/Extension/ModuleHandler.php
@@ -439,7 +439,12 @@ public function invokeAllDeprecated($hook, array $args = array()) {
   private function triggerDeprecationError($hook) {
     $modules = array_keys($this->getImplementationInfo($hook));
     if (!empty($modules)) {
-      @trigger_error('The following modules implement the deprecated hook hook_' . $hook . '(): ' . implode(', ', $modules), E_USER_DEPRECATED);
+      $message = 'The deprecated hook hook_' . $hook . '() is implemented in these functions: ';
+      $hooks = [];
+      foreach ($modules as $module) {
+        $hooks[] = $module . '_' . $hook . '()';
+      }
+      @trigger_error($message . implode(', ', $hooks), E_USER_DEPRECATED);
     }
   }
 
@@ -551,7 +556,7 @@ public function alterDeprecated($type, &$data, &$context1 = NULL, &$context2 = N
       $type = array_shift($extra_types);
     }
     if (!empty($this->alterFunctions[$cid])) {
-      $message = 'The deprecated alter hook hook_' . $type . '_alter() is implemented: ' . implode(', ', $this->alterFunctions[$cid]);
+      $message = 'The deprecated alter hook hook_' . $type . '_alter() is implemented in these functions: ' . implode(', ', $this->alterFunctions[$cid]);
       @trigger_error($message, E_USER_DEPRECATED);
     }
   }
diff --git a/core/modules/system/tests/modules/deprecation_test/deprecation_test.module b/core/modules/system/tests/modules/deprecation_test/deprecation_test.module
deleted file mode 100644
index 64bbe166dc..0000000000
--- a/core/modules/system/tests/modules/deprecation_test/deprecation_test.module
+++ /dev/null
@@ -1,14 +0,0 @@
-<?php
-
-/**
- * @file
- * Implements deprecated hooks to allow testing of the deprecation system.
- */
-
-function deprecation_test_deprecate_alter(&$data) {
-  $data[] = 'altered!';
-}
-
-function deprecation_test_deprecate() {
-  return 'hooked!';
-}
diff --git a/core/tests/Drupal/KernelTests/Core/Extension/ModuleHandlerTest.php b/core/tests/Drupal/KernelTests/Core/Extension/ModuleHandlerTest.php
deleted file mode 100644
index 6343381f8c..0000000000
--- a/core/tests/Drupal/KernelTests/Core/Extension/ModuleHandlerTest.php
+++ /dev/null
@@ -1,56 +0,0 @@
-<?php
-
-namespace Drupal\KernelTests\Core\Extension;
-
-use Drupal\KernelTests\KernelTestBase;
-
-/**
- * @coversDefaultClass \Drupal\Core\Extension\ModuleHandler
- * @group Extension
- * @group legacy
- */
-class ModuleHandlerTest extends KernelTestBase {
-
-  /**
-   * {@inheritdoc}
-   */
-  protected static $modules = ['deprecation_test'];
-
-  /**
-   * @covers ::alterDeprecated
-   * @expectedDeprecation The deprecated alter hook hook_deprecate_alter() is implemented: deprecation_test_deprecate_alter
-   */
-  public function testAlterDeprecated() {
-    /* @var $module_handler \Drupal\Core\Extension\ModuleHandler */
-    $module_handler = $this->container->get('module_handler');
-    $data = ['some', 'data'];
-    $module_handler->alterDeprecated('deprecate', $data);
-    $this->assertContains('altered!', $data);
-  }
-
-  /**
-   * @covers ::alterDeprecated
-   * @expectedDeprecation The following modules implement the deprecated hook hook_deprecate(): deprecation_test
-   */
-  public function testInvokeDeprecated() {
-    /* @var $module_handler \Drupal\Core\Extension\ModuleHandler */
-    $module_handler = $this->container->get('module_handler');
-    $this->assertEquals(
-      'hooked!',
-      $module_handler->invokeDeprecated('deprecation_test', 'deprecate')
-    );
-  }
-
-  /**
-   * @covers ::alterDeprecated
-   * @expectedDeprecation The following modules implement the deprecated hook hook_deprecate(): deprecation_test
-   */
-  public function testInvokeAllDeprecated() {
-    /* @var $module_handler \Drupal\Core\Extension\ModuleHandler */
-    $module_handler = $this->container->get('module_handler');
-    // The invokeAll() method returns an array of values from various
-    // implementations, so we have to find our known value in the result array.
-    $this->assertContains('hooked!', $module_handler->invokeAllDeprecated('deprecate'), true);
-  }
-
-}
diff --git a/core/tests/Drupal/Tests/Core/Extension/ModuleHandlerDeprecatedTest.php b/core/tests/Drupal/Tests/Core/Extension/ModuleHandlerDeprecatedTest.php
new file mode 100644
index 0000000000..1aa381fd09
--- /dev/null
+++ b/core/tests/Drupal/Tests/Core/Extension/ModuleHandlerDeprecatedTest.php
@@ -0,0 +1,84 @@
+<?php
+
+namespace Drupal\Tests\Core\Extension;
+
+use Drupal\Core\Extension\ModuleHandler;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * Tests special cases for hook deprecation methods.
+ *
+ * This is a separate class from Drupal\Tests\Core\Extension\ModuleHandlerTest
+ * so that we can mark it as belonging to the legacy group.
+ *
+ * @coversDefaultClass \Drupal\Core\Extension\ModuleHandler
+ *
+ * @group Extension
+ * @group legacy
+ *
+ * @see Drupal\Tests\Core\Extension\ModuleHandlerTest
+ */
+class ModuleHandlerDeprecatedTest extends UnitTestCase {
+
+  /**
+   * The mocked cache backend which is a dependency of ModuleHandler.
+   *
+   * @var \Drupal\Core\Cache\CacheBackendInterface|\PHPUnit_Framework_MockObject_MockObject
+   */
+  protected $cacheBackend;
+
+  /**
+   * The module handler under test.
+   *
+   * @var \Drupal\Core\Extension\ModuleHandlerInterface
+   */
+  protected $moduleHandler;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    $this->cacheBackend = $this->getMock('Drupal\Core\Cache\CacheBackendInterface');
+
+    $this->moduleHandler = new ModuleHandler($this->root, [], $this->cacheBackend);
+    $this->moduleHandler->addModule('module_handler_test_deprecated', 'core/tests/Drupal/Tests/Core/Extension/modules/module_handler_test_deprecated');
+    $this->moduleHandler->load('module_handler_test_deprecated');
+  }
+
+  /**
+   * @covers ::alterDeprecated
+   * @expectedDeprecation The deprecated alter hook hook_deprecate_alter() is implemented in these functions: module_handler_test_deprecated_deprecate_alter
+   */
+  public function testAlterDeprecated() {
+    $data = ['some', 'data'];
+    $this->moduleHandler->alterDeprecated('deprecate', $data);
+    $this->assertContains('altered', $data);
+  }
+
+  /**
+   * @covers ::invokeDeprecated
+   * @expectedDeprecation The deprecated hook hook_deprecate() is implemented in these functions: module_handler_test_deprecated_deprecate()
+   */
+  public function testInvokeDeprecated() {
+    $this->assertEquals(
+      'hooked',
+      $this->moduleHandler->invokeDeprecated('module_handler_test_deprecated', 'deprecate')
+    );
+  }
+
+  /**
+   * @covers ::invokeAllDeprecated
+   * @expectedDeprecation The deprecated hook hook_deprecate() is implemented in these functions: module_handler_test_deprecated_deprecate()
+   */
+  public function testInvokeAllDeprecated() {
+    // The invokeAll() method returns an array of values from various
+    // implementations, so we have to find our known value in the result array.
+    $this->assertContains(
+      'hooked',
+      $this->moduleHandler->invokeAllDeprecated('deprecate')
+    );
+  }
+
+}
diff --git a/core/tests/Drupal/Tests/Core/Extension/modules/module_handler_test_deprecated/module_handler_test_deprecated.info.yml b/core/tests/Drupal/Tests/Core/Extension/modules/module_handler_test_deprecated/module_handler_test_deprecated.info.yml
new file mode 100644
index 0000000000..b6dd0bf5fe
--- /dev/null
+++ b/core/tests/Drupal/Tests/Core/Extension/modules/module_handler_test_deprecated/module_handler_test_deprecated.info.yml
@@ -0,0 +1,7 @@
+name: module handler test deprecated module
+type: module
+description: 'Test module enabled in ModuleHandlerDeprecatedTest.'
+package: Testing
+version: VERSION
+core: 8.x
+
diff --git a/core/tests/Drupal/Tests/Core/Extension/modules/module_handler_test_deprecated/module_handler_test_deprecated.module b/core/tests/Drupal/Tests/Core/Extension/modules/module_handler_test_deprecated/module_handler_test_deprecated.module
new file mode 100644
index 0000000000..71cffa5480
--- /dev/null
+++ b/core/tests/Drupal/Tests/Core/Extension/modules/module_handler_test_deprecated/module_handler_test_deprecated.module
@@ -0,0 +1,14 @@
+<?php
+
+/**
+ * @file
+ * Implements deprecated hooks to allow testing of the deprecation system.
+ */
+
+function module_handler_test_deprecated_deprecate_alter(&$data) {
+  $data[] = 'altered';
+}
+
+function module_handler_test_deprecated_deprecate() {
+  return 'hooked';
+}