Fix for missing context reset of ComponentRegistrar

This test tries to setup a test environment with two modules and one
theme to test the generator.
During the test run, the test environment and the complete module stack
is processed by the generator.
So the test takes on my machine 25 seconds with xdebug enabled.
After resetting the registrar the complete test runs in ~50ms with
xdebug enabled.
Without the reset ~12.000 files are scanned. With the reset only 5 files
are scanned.

This test is not a unit test. It is an integration test.

Author: cmuench

app/code/Magento/Catalog/Test/Unit/Ui/DataProvider/Product/Form/Modifier/EavTest.php

@@ -490,6 +490,10 @@ public function testSetupAttributeMetaDefaultAttribute($productId, $productRequi
             ->method('getNote')
             ->willReturn($note);
 
+        $this->productAttributeMock->expects($this->any())
+            ->method('getDefaultFrontendLabel')
+            ->willReturn(new Phrase('mylabel'));
+
         $attributeMock = $this->getMockBuilder(AttributeInterface::class)
             ->setMethods(['getValue'])
             ->disableOriginalConstructor()
@@ -561,7 +565,7 @@ private function defaultNullProdNotNewAndRequired()
                 'required'    => true,
                 'notice'      => null,
                 'default'     => null,
-                'label'       => new Phrase(''),
+                'label'       => new Phrase('mylabel'),
                 'code'        => 'code',
                 'source'      => 'product-details',
                 'scopeLabel'  => '',
@@ -588,7 +592,7 @@ private function defaultNullProdNotNewAndNotRequired()
                 'required'    => false,
                 'notice'      => null,
                 'default'     => null,
-                'label'       => new Phrase(''),
+                'label'       => new Phrase('mylabel'),
                 'code'        => 'code',
                 'source'      => 'product-details',
                 'scopeLabel'  => '',
@@ -615,7 +619,7 @@ private function defaultNullProdNewAndNotRequired()
                 'required'    => false,
                 'notice'      => null,
                 'default'     => 'required_value',
-                'label'       => new Phrase(''),
+                'label'       => new Phrase('mylabel'),
                 'code'        => 'code',
                 'source'      => 'product-details',
                 'scopeLabel'  => '',
@@ -642,7 +646,7 @@ private function defaultNullProdNewAndRequired()
                 'required'    => false,
                 'notice'      => null,
                 'default'     => 'required_value',
-                'label'       => new Phrase(''),
+                'label'       => new Phrase('mylabel'),
                 'code'        => 'code',
                 'source'      => 'product-details',
                 'scopeLabel'  => '',
@@ -669,7 +673,7 @@ private function defaultNullProdNewAndRequiredAndFilledNotice()
                 'required'    => false,
                 'notice'      => __('example notice'),
                 'default'     => 'required_value',
-                'label'       => new Phrase(''),
+                'label'       => new Phrase('mylabel'),
                 'code'        => 'code',
                 'source'      => 'product-details',
                 'scopeLabel'  => '',

dev/tests/integration/testsuite/Magento/Setup/Module/I18n/Dictionary/GeneratorTest.php

@@ -6,6 +6,7 @@
 namespace Magento\Setup\Module\I18n\Dictionary;
 
 use Magento\Framework\Component\ComponentRegistrar;
+use Magento\Setup\Module\I18n\Dictionary\Generator;
 use Magento\Setup\Module\I18n\ServiceLocator;
 
 class GeneratorTest extends \PHPUnit\Framework\TestCase
@@ -46,6 +47,7 @@ protected function setUp()
         $paths = $reflection->getProperty('paths');
         $paths->setAccessible(true);
         $this->backupRegistrar = $paths->getValue();
+        $paths->setValue(['module' => [], 'theme' => []]);
         $paths->setAccessible(false);
 
         $this->testDir = realpath(__DIR__ . '/_files');