diff --git a/dev/tests/integration/testsuite/Magento/Framework/Code/GeneratorTest.php b/dev/tests/integration/testsuite/Magento/Framework/Code/GeneratorTest.php
index d74a83c339326..a43013860c79c 100644
--- a/dev/tests/integration/testsuite/Magento/Framework/Code/GeneratorTest.php
+++ b/dev/tests/integration/testsuite/Magento/Framework/Code/GeneratorTest.php
@@ -5,12 +5,13 @@
  */
 namespace Magento\Framework\Code;
 
-use Magento\Framework\Code\Generator;
+use Magento\Framework\Api\Code\Generator\ExtensionAttributesInterfaceFactoryGenerator;
 use Magento\Framework\App\Filesystem\DirectoryList;
+use Magento\Framework\Filesystem;
 use Magento\Framework\Interception\Code\Generator as InterceptionGenerator;
 use Magento\Framework\ObjectManager\Code\Generator as DIGenerator;
-use Magento\Framework\Api\Code\Generator\ExtensionAttributesInterfaceFactoryGenerator;
 use Magento\TestFramework\Helper\Bootstrap;
+use PHPUnit\Framework\TestCase;
 
 require_once __DIR__ . '/GeneratorTest/SourceClassWithNamespace.php';
 require_once __DIR__ . '/GeneratorTest/ParentClassWithNamespace.php';
@@ -18,60 +19,77 @@
 
 /**
  * @magentoAppIsolation enabled
+ * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
  */
-class GeneratorTest extends \PHPUnit\Framework\TestCase
+class GeneratorTest extends TestCase
 {
-    const CLASS_NAME_WITH_NAMESPACE = \Magento\Framework\Code\GeneratorTest\SourceClassWithNamespace::class;
+    const CLASS_NAME_WITH_NAMESPACE = GeneratorTest\SourceClassWithNamespace::class;
 
     /**
-     * @var \Magento\Framework\Code\Generator
+     * @var Generator
      */
     protected $_generator;
 
     /**
-     * @var \Magento\Framework\Code\Generator\Io
+     * @var Generator/Io
      */
     protected $_ioObject;
 
     /**
-     * @var \Magento\Framework\Filesystem\Directory\Write
+     * @var Filesystem\Directory\Write
+     */
+    private $generatedDirectory;
+
+    /**
+     * @var Filesystem\Directory\Read
+     */
+    private $logDirectory;
+
+    /**
+     * @var string
      */
-    protected $varDirectory;
+    private $testRelativePath = './Magento/Framework/Code/GeneratorTest/';
 
+    /**
+     * @inheritdoc
+     */
     protected function setUp()
     {
-        $objectManager = \Magento\TestFramework\Helper\Bootstrap::getObjectManager();
-        $this->varDirectory = $objectManager->get(
-            \Magento\Framework\Filesystem::class
-        )->getDirectoryWrite(
-            DirectoryList::VAR_DIR
-        );
-        $generationDirectory = $this->varDirectory->getAbsolutePath('generation');
-        $this->_ioObject = new \Magento\Framework\Code\Generator\Io(
-            new \Magento\Framework\Filesystem\Driver\File(),
-            $generationDirectory
-        );
+        $objectManager = Bootstrap::getObjectManager();
+        /** @var Filesystem $filesystem */
+        $filesystem = $objectManager->get(Filesystem::class);
+        $this->generatedDirectory = $filesystem->getDirectoryWrite(DirectoryList::GENERATED_CODE);
+        $this->logDirectory = $filesystem->getDirectoryRead(DirectoryList::LOG);
+        $generatedDirectoryAbsolutePath = $this->generatedDirectory->getAbsolutePath();
+        $this->_ioObject = new Generator\Io(new Filesystem\Driver\File(), $generatedDirectoryAbsolutePath);
         $this->_generator = $objectManager->create(
-            \Magento\Framework\Code\Generator::class,
+            Generator::class,
             [
                 'ioObject' => $this->_ioObject,
                 'generatedEntities' => [
                     ExtensionAttributesInterfaceFactoryGenerator::ENTITY_TYPE =>
                         ExtensionAttributesInterfaceFactoryGenerator::class,
-                    DIGenerator\Factory::ENTITY_TYPE => \Magento\Framework\ObjectManager\Code\Generator\Factory::class,
-                    DIGenerator\Proxy::ENTITY_TYPE => \Magento\Framework\ObjectManager\Code\Generator\Proxy::class,
-                    InterceptionGenerator\Interceptor::ENTITY_TYPE =>
-                        \Magento\Framework\Interception\Code\Generator\Interceptor::class,
+                    DIGenerator\Factory::ENTITY_TYPE => DIGenerator\Factory::class,
+                    DIGenerator\Proxy::ENTITY_TYPE => DIGenerator\Proxy::class,
+                    InterceptionGenerator\Interceptor::ENTITY_TYPE => InterceptionGenerator\Interceptor::class,
                 ]
             ]
         );
         $this->_generator->setObjectManager($objectManager);
     }
 
+    /**
+     * @inheritdoc
+     */
     protected function tearDown()
     {
-        $this->varDirectory->delete('generation');
         $this->_generator = null;
+        if ($this->generatedDirectory->isExist($this->testRelativePath)) {
+            if (!$this->generatedDirectory->isWritable($this->testRelativePath)) {
+                $this->generatedDirectory->changePermissionsRecursively($this->testRelativePath, 0775, 0664);
+            }
+            $this->generatedDirectory->delete($this->testRelativePath);
+        }
     }
 
     protected function _clearDocBlock($classBody)
@@ -79,81 +97,59 @@ protected function _clearDocBlock($classBody)
         return preg_replace('/(\/\*[\w\W]*)\nclass/', 'class', $classBody);
     }
 
+    /**
+     * Generates a new file with Factory class and compares with the sample from the
+     * SourceClassWithNamespaceFactory.php.sample file.
+     */
     public function testGenerateClassFactoryWithNamespace()
     {
         $factoryClassName = self::CLASS_NAME_WITH_NAMESPACE . 'Factory';
-        $result = false;
-        $generatorResult = $this->_generator->generateClass($factoryClassName);
-        if (\Magento\Framework\Code\Generator::GENERATION_ERROR !== $generatorResult) {
-            $result = true;
-        }
-        $this->assertTrue($result, 'Failed asserting that \'' . (string)$generatorResult . '\' equals \'success\'.');
-
-        $factory = \Magento\TestFramework\Helper\Bootstrap::getObjectManager()->create($factoryClassName);
-
-        $object = $factory->create();
-        $this->assertInstanceOf(self::CLASS_NAME_WITH_NAMESPACE, $object);
-
-        // This test is only valid if the factory created the object if Autoloader did not pick it up automatically
-        if (\Magento\Framework\Code\Generator::GENERATION_SUCCESS == $generatorResult) {
-            $content = $this->_clearDocBlock(
-                file_get_contents(
-                    $this->_ioObject->generateResultFileName(self::CLASS_NAME_WITH_NAMESPACE . 'Factory')
-                )
-            );
-            $expectedContent = $this->_clearDocBlock(
-                file_get_contents(__DIR__ . '/_expected/SourceClassWithNamespaceFactory.php.sample')
-            );
-            $this->assertEquals($expectedContent, $content);
-        }
+        $this->assertEquals(Generator::GENERATION_SUCCESS, $this->_generator->generateClass($factoryClassName));
+        $factory = Bootstrap::getObjectManager()->create($factoryClassName);
+        $this->assertInstanceOf(self::CLASS_NAME_WITH_NAMESPACE, $factory->create());
+        $content = $this->_clearDocBlock(
+            file_get_contents($this->_ioObject->generateResultFileName($factoryClassName))
+        );
+        $expectedContent = $this->_clearDocBlock(
+            file_get_contents(__DIR__ . '/_expected/SourceClassWithNamespaceFactory.php.sample')
+        );
+        $this->assertEquals($expectedContent, $content);
     }
 
+    /**
+     * Generates a new file with Proxy class and compares with the sample from the
+     * SourceClassWithNamespaceProxy.php.sample file.
+     */
     public function testGenerateClassProxyWithNamespace()
     {
         $proxyClassName = self::CLASS_NAME_WITH_NAMESPACE . '\Proxy';
-        $result = false;
-        $generatorResult = $this->_generator->generateClass($proxyClassName);
-        if (\Magento\Framework\Code\Generator::GENERATION_ERROR !== $generatorResult) {
-            $result = true;
-        }
-        $this->assertTrue($result, 'Failed asserting that \'' . (string)$generatorResult . '\' equals \'success\'.');
-
-        $proxy = \Magento\TestFramework\Helper\Bootstrap::getObjectManager()->create($proxyClassName);
+        $this->assertEquals(Generator::GENERATION_SUCCESS, $this->_generator->generateClass($proxyClassName));
+        $proxy = Bootstrap::getObjectManager()->create($proxyClassName);
         $this->assertInstanceOf(self::CLASS_NAME_WITH_NAMESPACE, $proxy);
-
-        // This test is only valid if the factory created the object if Autoloader did not pick it up automatically
-        if (\Magento\Framework\Code\Generator::GENERATION_SUCCESS == $generatorResult) {
-            $content = $this->_clearDocBlock(
-                file_get_contents($this->_ioObject->generateResultFileName(self::CLASS_NAME_WITH_NAMESPACE . '\Proxy'))
-            );
-            $expectedContent = $this->_clearDocBlock(
-                file_get_contents(__DIR__ . '/_expected/SourceClassWithNamespaceProxy.php.sample')
-            );
-            $this->assertEquals($expectedContent, $content);
-        }
+        $content = $this->_clearDocBlock(
+            file_get_contents($this->_ioObject->generateResultFileName($proxyClassName))
+        );
+        $expectedContent = $this->_clearDocBlock(
+            file_get_contents(__DIR__ . '/_expected/SourceClassWithNamespaceProxy.php.sample')
+        );
+        $this->assertEquals($expectedContent, $content);
     }
 
+    /**
+     * Generates a new file with Interceptor class and compares with the sample from the
+     * SourceClassWithNamespaceInterceptor.php.sample file.
+     */
     public function testGenerateClassInterceptorWithNamespace()
     {
         $interceptorClassName = self::CLASS_NAME_WITH_NAMESPACE . '\Interceptor';
-        $result = false;
-        $generatorResult = $this->_generator->generateClass($interceptorClassName);
-        if (\Magento\Framework\Code\Generator::GENERATION_ERROR !== $generatorResult) {
-            $result = true;
-        }
-        $this->assertTrue($result, 'Failed asserting that \'' . (string)$generatorResult . '\' equals \'success\'.');
-
-        if (\Magento\Framework\Code\Generator::GENERATION_SUCCESS == $generatorResult) {
-            $content = $this->_clearDocBlock(
-                file_get_contents(
-                    $this->_ioObject->generateResultFileName(self::CLASS_NAME_WITH_NAMESPACE . '\Interceptor')
-                )
-            );
-            $expectedContent = $this->_clearDocBlock(
-                file_get_contents(__DIR__ . '/_expected/SourceClassWithNamespaceInterceptor.php.sample')
-            );
-            $this->assertEquals($expectedContent, $content);
-        }
+        $this->assertEquals(Generator::GENERATION_SUCCESS, $this->_generator->generateClass($interceptorClassName));
+        $content = $this->_clearDocBlock(
+            file_get_contents($this->_ioObject->generateResultFileName($interceptorClassName))
+        );
+        $expectedContent = $this->_clearDocBlock(
+            file_get_contents(__DIR__ . '/_expected/SourceClassWithNamespaceInterceptor.php.sample')
+        );
+        $this->assertEquals($expectedContent, $content);
     }
 
     /**
@@ -163,26 +159,35 @@ public function testGenerateClassInterceptorWithNamespace()
     public function testGenerateClassExtensionAttributesInterfaceFactoryWithNamespace()
     {
         $factoryClassName = self::CLASS_NAME_WITH_NAMESPACE . 'ExtensionInterfaceFactory';
-        $this->varDirectory->create(
-            $this->varDirectory->getAbsolutePath('generation') . '/Magento/Framework/Code/GeneratorTest/'
-        );
-
-        $generatorResult = $this->_generator->generateClass($factoryClassName);
-
+        $this->generatedDirectory->create($this->testRelativePath);
+        $this->assertEquals(Generator::GENERATION_SUCCESS, $this->_generator->generateClass($factoryClassName));
         $factory = Bootstrap::getObjectManager()->create($factoryClassName);
-        $object = $factory->create();
-
-        $this->assertEquals($generatorResult, Generator::GENERATION_SUCCESS);
-        $this->assertInstanceOf(self::CLASS_NAME_WITH_NAMESPACE . 'Extension', $object);
-
+        $this->assertInstanceOf(self::CLASS_NAME_WITH_NAMESPACE . 'Extension', $factory->create());
         $content = $this->_clearDocBlock(
-            file_get_contents(
-                $this->_ioObject->generateResultFileName(self::CLASS_NAME_WITH_NAMESPACE . 'ExtensionInterfaceFactory')
-            )
+            file_get_contents($this->_ioObject->generateResultFileName($factoryClassName))
         );
         $expectedContent = $this->_clearDocBlock(
             file_get_contents(__DIR__ . '/_expected/SourceClassWithNamespaceExtensionInterfaceFactory.php.sample')
         );
         $this->assertEquals($expectedContent, $content);
     }
+
+    /**
+     * It tries to generate a new class file when the generated directory is read-only
+     */
+    public function testGeneratorClassWithErrorSaveClassFile()
+    {
+        $factoryClassName = self::CLASS_NAME_WITH_NAMESPACE . 'Factory';
+        $msgPart = 'Class ' . $factoryClassName . ' generation error: The requested class did not generate properly, '
+            . 'because the \'generated\' directory permission is read-only.';
+        $regexpMsgPart = preg_quote($msgPart);
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessageRegExp("/.*$regexpMsgPart.*/");
+        $this->generatedDirectory->create($this->testRelativePath);
+        $this->generatedDirectory->changePermissionsRecursively($this->testRelativePath, 0555, 0444);
+        $generatorResult = $this->_generator->generateClass($factoryClassName);
+        $this->assertFalse($generatorResult);
+        $pathToSystemLog = $this->logDirectory->getAbsolutePath('system.log');
+        $this->assertContains($msgPart, file_get_contents($pathToSystemLog));
+    }
 }
diff --git a/lib/internal/Magento/Framework/Code/Generator.php b/lib/internal/Magento/Framework/Code/Generator.php
index 0b807775e032a..20b226aa8283a 100644
--- a/lib/internal/Magento/Framework/Code/Generator.php
+++ b/lib/internal/Magento/Framework/Code/Generator.php
@@ -7,6 +7,11 @@
 
 use Magento\Framework\Code\Generator\DefinedClasses;
 use Magento\Framework\Code\Generator\EntityAbstract;
+use Magento\Framework\Code\Generator\Io;
+use Magento\Framework\ObjectManagerInterface;
+use Magento\Framework\Phrase;
+use Magento\Framework\Filesystem\Driver\File;
+use Psr\Log\LoggerInterface;
 
 class Generator
 {
@@ -17,7 +22,7 @@ class Generator
     const GENERATION_SKIP = 'skip';
 
     /**
-     * @var \Magento\Framework\Code\Generator\Io
+     * @var Io
      */
     protected $_ioObject;
 
@@ -32,26 +37,33 @@ class Generator
     protected $definedClasses;
 
     /**
-     * @var \Magento\Framework\ObjectManagerInterface
+     * @var ObjectManagerInterface
      */
     protected $objectManager;
 
     /**
-     * @param Generator\Io   $ioObject
-     * @param array          $generatedEntities
+     * Logger instance
+     *
+     * @var LoggerInterface
+     */
+    private $logger;
+
+    /**
+     * @param Generator\Io $ioObject
+     * @param array $generatedEntities
      * @param DefinedClasses $definedClasses
+     * @param LoggerInterface $logger
      */
     public function __construct(
-        \Magento\Framework\Code\Generator\Io $ioObject = null,
+        Io $ioObject = null,
         array $generatedEntities = [],
-        DefinedClasses $definedClasses = null
+        DefinedClasses $definedClasses = null,
+        LoggerInterface $logger = null
     ) {
-        $this->_ioObject = $ioObject
-            ?: new \Magento\Framework\Code\Generator\Io(
-                new \Magento\Framework\Filesystem\Driver\File()
-            );
+        $this->_ioObject = $ioObject ?: new Io(new File());
         $this->definedClasses = $definedClasses ?: new DefinedClasses();
         $this->_generatedEntities = $generatedEntities;
+        $this->logger = $logger;
     }
 
     /**
@@ -111,8 +123,16 @@ public function generateClass($className)
         if ($generator !== null) {
             $this->tryToLoadSourceClass($className, $generator);
             if (!($file = $generator->generate())) {
+                /** @var $logger LoggerInterface */
                 $errors = $generator->getErrors();
-                throw new \RuntimeException(implode(' ', $errors) . ' in [' . $className . ']');
+                $errors[] = 'Class ' . $className . ' generation error: The requested class did not generate properly, '
+                    . 'because the \'generated\' directory permission is read-only. '
+                    . 'If --- after running the \'bin/magento setup:di:compile\' CLI command when the \'generated\' '
+                    . 'directory permission is set to write --- the requested class did not generate properly, then '
+                    . 'you must add the generated class object to the signature of the related construct method, only.';
+                $message = implode(PHP_EOL, $errors);
+                $this->getLogger()->critical($message);
+                throw new \RuntimeException($message);
             }
             if (!$this->definedClasses->isClassLoadableFromMemory($className)) {
                 $this->_ioObject->includeFile($file);
@@ -121,13 +141,26 @@ public function generateClass($className)
         }
     }
 
+    /**
+     * Retrieve logger
+     *
+     * @return LoggerInterface
+     */
+    private function getLogger()
+    {
+        if (!$this->logger) {
+            $this->logger = $this->getObjectManager()->get(LoggerInterface::class);
+        }
+        return $this->logger;
+    }
+
     /**
      * Create entity generator
      *
      * @param string $generatorClass
      * @param string $entityName
      * @param string $className
-     * @return \Magento\Framework\Code\Generator\EntityAbstract
+     * @return EntityAbstract
      */
     protected function createGeneratorInstance($generatorClass, $entityName, $className)
     {
@@ -140,10 +173,10 @@ protected function createGeneratorInstance($generatorClass, $entityName, $classN
     /**
      * Set object manager instance.
      *
-     * @param \Magento\Framework\ObjectManagerInterface $objectManager
+     * @param ObjectManagerInterface $objectManager
      * @return $this
      */
-    public function setObjectManager(\Magento\Framework\ObjectManagerInterface $objectManager)
+    public function setObjectManager(ObjectManagerInterface $objectManager)
     {
         $this->objectManager = $objectManager;
         return $this;
@@ -152,11 +185,11 @@ public function setObjectManager(\Magento\Framework\ObjectManagerInterface $obje
     /**
      * Get object manager instance.
      *
-     * @return \Magento\Framework\ObjectManagerInterface
+     * @return ObjectManagerInterface
      */
     public function getObjectManager()
     {
-        if (!($this->objectManager instanceof \Magento\Framework\ObjectManagerInterface)) {
+        if (!($this->objectManager instanceof ObjectManagerInterface)) {
             throw new \LogicException(
                 "Object manager was expected to be set using setObjectManger() "
                 . "before getObjectManager() invocation."
@@ -169,7 +202,7 @@ public function getObjectManager()
      * Try to load/generate source class to check if it is valid or not.
      *
      * @param string $className
-     * @param \Magento\Framework\Code\Generator\EntityAbstract $generator
+     * @param EntityAbstract $generator
      * @return void
      * @throws \RuntimeException
      */
@@ -178,7 +211,7 @@ protected function tryToLoadSourceClass($className, $generator)
         $sourceClassName = $generator->getSourceClassName();
         if (!$this->definedClasses->isClassLoadable($sourceClassName)) {
             if ($this->generateClass($sourceClassName) !== self::GENERATION_SUCCESS) {
-                $phrase = new \Magento\Framework\Phrase(
+                $phrase = new Phrase(
                     'Source class "%1" for "%2" generation does not exist.',
                     [$sourceClassName, $className]
                 );
diff --git a/lib/internal/Magento/Framework/Code/Test/Unit/GeneratorTest.php b/lib/internal/Magento/Framework/Code/Test/Unit/GeneratorTest.php
index c175c0fe9be85..b6a4e545fea32 100644
--- a/lib/internal/Magento/Framework/Code/Test/Unit/GeneratorTest.php
+++ b/lib/internal/Magento/Framework/Code/Test/Unit/GeneratorTest.php
@@ -3,14 +3,22 @@
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
-
 namespace Magento\Framework\Code\Test\Unit;
 
 use Magento\Framework\Code\Generator;
 use Magento\Framework\Code\Generator\DefinedClasses;
 use Magento\Framework\Code\Generator\Io;
-
-class GeneratorTest extends \PHPUnit\Framework\TestCase
+use Psr\Log\LoggerInterface;
+use Magento\Framework\ObjectManager\Code\Generator\Factory;
+use Magento\Framework\ObjectManager\Code\Generator\Proxy;
+use Magento\Framework\Interception\Code\Generator\Interceptor;
+use PHPUnit_Framework_MockObject_MockObject as Mock;
+use PHPUnit\Framework\TestCase;
+use Magento\Framework\ObjectManagerInterface;
+use Magento\Framework\Code\Generator\EntityAbstract;
+use Magento\GeneratedClass\Factory as GeneratedClassFactory;
+
+class GeneratorTest extends TestCase
 {
     /**
      * Class name parameter value
@@ -22,45 +30,57 @@ class GeneratorTest extends \PHPUnit\Framework\TestCase
      *
      * @var array
      */
-    protected $expectedEntities = [
-        'factory' => \Magento\Framework\ObjectManager\Code\Generator\Factory::ENTITY_TYPE,
-        'proxy' => \Magento\Framework\ObjectManager\Code\Generator\Proxy::ENTITY_TYPE,
-        'interceptor' => \Magento\Framework\Interception\Code\Generator\Interceptor::ENTITY_TYPE,
+    private $expectedEntities = [
+        'factory' => Factory::ENTITY_TYPE,
+        'proxy' => Proxy::ENTITY_TYPE,
+        'interceptor' => Interceptor::ENTITY_TYPE,
     ];
 
     /**
      * System under test
      *
-     * @var \Magento\Framework\Code\Generator
+     * @var Generator
      */
-    protected $model;
+    private $model;
 
-    /** @var \PHPUnit_Framework_MockObject_MockObject|Io */
-    protected $ioObjectMock;
+    /**
+     * @var Io|Mock
+     */
+    private $ioObjectMock;
 
-    /** @var \Magento\Framework\Code\Generator\DefinedClasses | \PHPUnit_Framework_MockObject_MockObject */
-    protected $definedClassesMock;
+    /**
+     * @var DefinedClasses|Mock
+     */
+    private $definedClassesMock;
+
+    /**
+     * @var LoggerInterface|Mock
+     */
+    private $loggerMock;
 
     protected function setUp()
     {
-        $this->definedClassesMock = $this->createMock(\Magento\Framework\Code\Generator\DefinedClasses::class);
-        $this->ioObjectMock = $this->getMockBuilder(\Magento\Framework\Code\Generator\Io::class)
+        $this->definedClassesMock = $this->createMock(DefinedClasses::class);
+        $this->ioObjectMock = $this->getMockBuilder(Io::class)
             ->disableOriginalConstructor()
             ->getMock();
-        $this->model = $this->buildModel(
+        $this->loggerMock = $this->getMockForAbstractClass(LoggerInterface::class);
+
+        $this->model = new Generator(
             $this->ioObjectMock,
             [
-                'factory' => \Magento\Framework\ObjectManager\Code\Generator\Factory::class,
-                'proxy' => \Magento\Framework\ObjectManager\Code\Generator\Proxy::class,
-                'interceptor' => \Magento\Framework\Interception\Code\Generator\Interceptor::class
+                'factory' => Factory::class,
+                'proxy' => Proxy::class,
+                'interceptor' => Interceptor::class,
             ],
-            $this->definedClassesMock
+            $this->definedClassesMock,
+            $this->loggerMock
         );
     }
 
     public function testGetGeneratedEntities()
     {
-        $this->model = $this->buildModel(
+        $this->model = new Generator(
             $this->ioObjectMock,
             ['factory', 'proxy', 'interceptor'],
             $this->definedClassesMock
@@ -69,14 +89,16 @@ public function testGetGeneratedEntities()
     }
 
     /**
+     * @param string $className
+     * @param string $entityType
      * @expectedException \RuntimeException
      * @dataProvider generateValidClassDataProvider
      */
     public function testGenerateClass($className, $entityType)
     {
-        $objectManagerMock = $this->createMock(\Magento\Framework\ObjectManagerInterface::class);
+        $objectManagerMock = $this->createMock(ObjectManagerInterface::class);
         $fullClassName = $className . $entityType;
-        $entityGeneratorMock = $this->getMockBuilder(\Magento\Framework\Code\Generator\EntityAbstract::class)
+        $entityGeneratorMock = $this->getMockBuilder(EntityAbstract::class)
             ->disableOriginalConstructor()
             ->getMock();
         $objectManagerMock->expects($this->once())->method('create')->willReturn($entityGeneratorMock);
@@ -87,7 +109,7 @@ public function testGenerateClass($className, $entityType)
     public function testGenerateClassWithWrongName()
     {
         $this->assertEquals(
-            \Magento\Framework\Code\Generator::GENERATION_ERROR,
+            Generator::GENERATION_ERROR,
             $this->model->generateClass(self::SOURCE_CLASS)
         );
     }
@@ -95,12 +117,12 @@ public function testGenerateClassWithWrongName()
     /**
      * @expectedException \RuntimeException
      */
-    public function testGenerateClassWithError()
+    public function testGenerateClassWhenClassIsNotGenerationSuccess()
     {
         $expectedEntities = array_values($this->expectedEntities);
         $resultClassName = self::SOURCE_CLASS . ucfirst(array_shift($expectedEntities));
-        $objectManagerMock = $this->createMock(\Magento\Framework\ObjectManagerInterface::class);
-        $entityGeneratorMock = $this->getMockBuilder(\Magento\Framework\Code\Generator\EntityAbstract::class)
+        $objectManagerMock = $this->createMock(ObjectManagerInterface::class);
+        $entityGeneratorMock = $this->getMockBuilder(EntityAbstract::class)
             ->disableOriginalConstructor()
             ->getMock();
         $objectManagerMock->expects($this->once())->method('create')->willReturn($entityGeneratorMock);
@@ -108,6 +130,57 @@ public function testGenerateClassWithError()
         $this->model->generateClass($resultClassName);
     }
 
+    /**
+     * @inheritdoc
+     */
+    public function testGenerateClassWithErrors()
+    {
+        $expectedEntities = array_values($this->expectedEntities);
+        $resultClassName = self::SOURCE_CLASS . ucfirst(array_shift($expectedEntities));
+        $errorMessages = [
+            'Error message 0',
+            'Error message 1',
+            'Error message 2',
+        ];
+        $mainErrorMessage = 'Class ' . $resultClassName . ' generation error: The requested class did not generate '
+            . 'properly, because the \'generated\' directory permission is read-only. '
+            . 'If --- after running the \'bin/magento setup:di:compile\' CLI command when the \'generated\' '
+            . 'directory permission is set to write --- the requested class did not generate properly, then '
+            . 'you must add the generated class object to the signature of the related construct method, only.';
+        $FinalErrorMessage = implode(PHP_EOL, $errorMessages) . "\n" . $mainErrorMessage;
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage($FinalErrorMessage);
+
+        /** @var ObjectManagerInterface|Mock $objectManagerMock */
+        $objectManagerMock = $this->createMock(ObjectManagerInterface::class);
+        /** @var EntityAbstract|Mock $entityGeneratorMock */
+        $entityGeneratorMock = $this->getMockBuilder(EntityAbstract::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $objectManagerMock->expects($this->once())
+            ->method('create')
+            ->willReturn($entityGeneratorMock);
+        $entityGeneratorMock->expects($this->once())
+            ->method('getSourceClassName')
+            ->willReturn(self::SOURCE_CLASS);
+        $this->definedClassesMock->expects($this->once())
+            ->method('isClassLoadable')
+            ->with(self::SOURCE_CLASS)
+            ->willReturn(true);
+        $entityGeneratorMock->expects($this->once())
+            ->method('generate')
+            ->willReturn(false);
+        $entityGeneratorMock->expects($this->once())
+            ->method('getErrors')
+            ->willReturn($errorMessages);
+        $this->loggerMock->expects($this->once())
+            ->method('critical')
+            ->with($FinalErrorMessage);
+        $this->model->setObjectManager($objectManagerMock);
+        $this->model->generateClass($resultClassName);
+    }
+
     /**
      * @dataProvider trueFalseDataProvider
      */
@@ -124,14 +197,11 @@ public function testGenerateClassWithExistName($fileExists)
         $this->ioObjectMock->expects($this->exactly($includeFileInvokeCount))->method('includeFile');
 
         $this->assertEquals(
-            \Magento\Framework\Code\Generator::GENERATION_SKIP,
-            $this->model->generateClass(\Magento\GeneratedClass\Factory::class)
+            Generator::GENERATION_SKIP,
+            $this->model->generateClass(GeneratedClassFactory::class)
         );
     }
 
-    /**
-     * @return array
-     */
     public function trueFalseDataProvider()
     {
         return [[true], [false]];
@@ -154,17 +224,4 @@ public function generateValidClassDataProvider()
         }
         return $data;
     }
-
-    /**
-     * Build SUT object
-     *
-     * @param Io $ioObject
-     * @param array $generatedEntities
-     * @param DefinedClasses $definedClasses
-     * @return Generator
-     */
-    private function buildModel(Io $ioObject, array $generatedEntities, DefinedClasses $definedClasses)
-    {
-        return new Generator($ioObject, $generatedEntities, $definedClasses);
-    }
 }