diff --git a/src/Symfony/Bundle/FrameworkBundle/Tests/CacheWarmer/ValidatorCacheWarmerTest.php b/src/Symfony/Bundle/FrameworkBundle/Tests/CacheWarmer/ValidatorCacheWarmerTest.php
index d8626d8db5..16d27e5c7f 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Tests/CacheWarmer/ValidatorCacheWarmerTest.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Tests/CacheWarmer/ValidatorCacheWarmerTest.php
@@ -11,7 +11,6 @@
 
 namespace Symfony\Bundle\FrameworkBundle\Tests\CacheWarmer;
 
-use PHPUnit\Framework\Warning;
 use Symfony\Bundle\FrameworkBundle\CacheWarmer\ValidatorCacheWarmer;
 use Symfony\Bundle\FrameworkBundle\Tests\TestCase;
 use Symfony\Component\Cache\Adapter\NullAdapter;
@@ -21,12 +20,11 @@ use Symfony\Component\Validator\ValidatorBuilder;
 
 class ValidatorCacheWarmerTest extends TestCase
 {
+    /**
+     * @runInSeparateProcess https://github.com/symfony/symfony/issues/32995
+     */
     public function testWarmUp()
     {
-        if (\PHP_VERSION_ID >= 70400) {
-            throw new Warning('PHP 7.4 breaks this test, see https://bugs.php.net/78351.');
-        }
-
         $validatorBuilder = new ValidatorBuilder();
         $validatorBuilder->addXmlMapping(__DIR__.'/../Fixtures/Validation/Resources/person.xml');
         $validatorBuilder->addYamlMapping(__DIR__.'/../Fixtures/Validation/Resources/author.yml');
diff --git a/src/Symfony/Component/Cache/Tests/Adapter/AdapterTestCase.php b/src/Symfony/Component/Cache/Tests/Adapter/AdapterTestCase.php
index bf14fbbb7e..1b0091e07d 100644
--- a/src/Symfony/Component/Cache/Tests/Adapter/AdapterTestCase.php
+++ b/src/Symfony/Component/Cache/Tests/Adapter/AdapterTestCase.php
@@ -254,12 +254,11 @@ abstract class AdapterTestCase extends CachePoolTest
         $this->assertTrue($this->isPruned($cache, 'qux'));
     }
 
+    /**
+     * @runInSeparateProcess https://github.com/symfony/symfony/issues/32995
+     */
     public function testSavingObject()
     {
-        if (\PHP_VERSION_ID >= 70400) {
-            throw new Warning('PHP 7.4 breaks this test, see https://bugs.php.net/78351.');
-        }
-
         parent::testSavingObject();
     }
 }
diff --git a/src/Symfony/Component/Config/Tests/Resource/ClassExistenceResourceTest.php b/src/Symfony/Component/Config/Tests/Resource/ClassExistenceResourceTest.php
index 5b1ec6461f..44450c32b7 100644
--- a/src/Symfony/Component/Config/Tests/Resource/ClassExistenceResourceTest.php
+++ b/src/Symfony/Component/Config/Tests/Resource/ClassExistenceResourceTest.php
@@ -12,7 +12,6 @@
 namespace Symfony\Component\Config\Tests\Resource;
 
 use PHPUnit\Framework\TestCase;
-use PHPUnit\Framework\Warning;
 use Symfony\Component\Config\Resource\ClassExistenceResource;
 use Symfony\Component\Config\Tests\Fixtures\BadParent;
 use Symfony\Component\Config\Tests\Fixtures\Resource\ConditionalClass;
@@ -76,23 +75,22 @@ EOF
         }
     }
 
+    /**
+     * @runInSeparateProcess https://github.com/symfony/symfony/issues/32995
+     */
     public function testBadParentWithTimestamp()
     {
-        if (\PHP_VERSION_ID >= 70400) {
-            throw new Warning('PHP 7.4 breaks this test, see https://bugs.php.net/78351.');
-        }
-
         $res = new ClassExistenceResource(BadParent::class, false);
         $this->assertTrue($res->isFresh(time()));
     }
 
+    /**
+     * @runInSeparateProcess https://github.com/symfony/symfony/issues/32995
+     */
     public function testBadParentWithNoTimestamp()
     {
         $this->expectException('ReflectionException');
         $this->expectExceptionMessage('Class Symfony\Component\Config\Tests\Fixtures\MissingParent not found');
-        if (\PHP_VERSION_ID >= 70400) {
-            throw new Warning('PHP 7.4 breaks this test, see https://bugs.php.net/78351.');
-        }
 
         $res = new ClassExistenceResource(BadParent::class, false);
         $res->isFresh(0);
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Compiler/AutowirePassTest.php b/src/Symfony/Component/DependencyInjection/Tests/Compiler/AutowirePassTest.php
index f3365a0128..5954044a63 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Compiler/AutowirePassTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Compiler/AutowirePassTest.php
@@ -12,7 +12,6 @@
 namespace Symfony\Component\DependencyInjection\Tests\Compiler;
 
 use PHPUnit\Framework\TestCase;
-use PHPUnit\Framework\Warning;
 use Psr\Log\LoggerInterface;
 use Psr\Log\NullLogger;
 use Symfony\Component\Config\FileLocator;
@@ -350,12 +349,11 @@ class AutowirePassTest extends TestCase
         }
     }
 
+    /**
+     * @runInSeparateProcess https://github.com/symfony/symfony/issues/32995
+     */
     public function testParentClassNotFoundThrowsException()
     {
-        if (\PHP_VERSION_ID >= 70400) {
-            throw new Warning('PHP 7.4 breaks this test, see https://bugs.php.net/78351.');
-        }
-
         $container = new ContainerBuilder();
 
         $aDefinition = $container->register('a', __NAMESPACE__.'\BadParentTypeHintedArgument');
@@ -627,12 +625,11 @@ class AutowirePassTest extends TestCase
         ];
     }
 
+    /**
+     * @runInSeparateProcess https://github.com/symfony/symfony/issues/32995
+     */
     public function testIgnoreServiceWithClassNotExisting()
     {
-        if (\PHP_VERSION_ID >= 70400) {
-            throw new Warning('PHP 7.4 breaks this test, see https://bugs.php.net/78351.');
-        }
-
         $container = new ContainerBuilder();
 
         $container->register('class_not_exist', __NAMESPACE__.'\OptionalServiceClass');
@@ -833,12 +830,11 @@ class AutowirePassTest extends TestCase
         }
     }
 
+    /**
+     * @runInSeparateProcess https://github.com/symfony/symfony/issues/32995
+     */
     public function testExceptionWhenAliasDoesNotExist()
     {
-        if (\PHP_VERSION_ID >= 70400) {
-            throw new Warning('PHP 7.4 breaks this test, see https://bugs.php.net/78351.');
-        }
-
         $container = new ContainerBuilder();
 
         // multiple I instances... but no IInterface alias
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Compiler/ResolveBindingsPassTest.php b/src/Symfony/Component/DependencyInjection/Tests/Compiler/ResolveBindingsPassTest.php
index 99a4a060ee..aa470f1e25 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Compiler/ResolveBindingsPassTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Compiler/ResolveBindingsPassTest.php
@@ -62,13 +62,13 @@ class ResolveBindingsPassTest extends TestCase
         $pass->process($container);
     }
 
+    /**
+     * @runInSeparateProcess https://github.com/symfony/symfony/issues/32995
+     */
     public function testMissingParent()
     {
         $this->expectException('Symfony\Component\DependencyInjection\Exception\InvalidArgumentException');
         $this->expectExceptionMessage('A binding is configured for an argument named "$quz" for service "Symfony\Component\DependencyInjection\Tests\Fixtures\ParentNotExists", but no corresponding argument has been found. It may be unused and should be removed, or it may have a typo.');
-        if (\PHP_VERSION_ID >= 70400) {
-            throw new Warning('PHP 7.4 breaks this test, see https://bugs.php.net/78351.');
-        }
 
         $container = new ContainerBuilder();
 
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Dumper/PhpDumperTest.php b/src/Symfony/Component/DependencyInjection/Tests/Dumper/PhpDumperTest.php
index 2cf47e66a2..c3cf3cfd1a 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Dumper/PhpDumperTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Dumper/PhpDumperTest.php
@@ -12,7 +12,6 @@
 namespace Symfony\Component\DependencyInjection\Tests\Dumper;
 
 use PHPUnit\Framework\TestCase;
-use PHPUnit\Framework\Warning;
 use Psr\Container\ContainerInterface;
 use Symfony\Component\Config\FileLocator;
 use Symfony\Component\DependencyInjection\Argument\IteratorArgument;
@@ -1044,12 +1043,11 @@ class PhpDumperTest extends TestCase
         $this->assertStringEqualsFile(self::$fixturesPath.'/php/services_inline_self_ref.php', $dumper->dump(['class' => 'Symfony_DI_PhpDumper_Test_Inline_Self_Ref']));
     }
 
+    /**
+     * @runInSeparateProcess https://github.com/symfony/symfony/issues/32995
+     */
     public function testHotPathOptimizations()
     {
-        if (\PHP_VERSION_ID >= 70400) {
-            throw new Warning('PHP 7.4 breaks this test, see https://bugs.php.net/78351.');
-        }
-
         $container = include self::$fixturesPath.'/containers/container_inline_requires.php';
         $container->setParameter('inline_requires', true);
         $container->compile();
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Loader/FileLoaderTest.php b/src/Symfony/Component/DependencyInjection/Tests/Loader/FileLoaderTest.php
index 622248fae1..b5a6911254 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Loader/FileLoaderTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Loader/FileLoaderTest.php
@@ -12,7 +12,6 @@
 namespace Symfony\Component\DependencyInjection\Tests\Loader;
 
 use PHPUnit\Framework\TestCase;
-use PHPUnit\Framework\Warning;
 use Psr\Container\ContainerInterface as PsrContainerInterface;
 use Symfony\Component\Config\FileLocator;
 use Symfony\Component\Config\Loader\LoaderResolver;
@@ -107,12 +106,11 @@ class FileLoaderTest extends TestCase
         );
     }
 
+    /**
+     * @runInSeparateProcess https://github.com/symfony/symfony/issues/32995
+     */
     public function testRegisterClassesWithExclude()
     {
-        if (\PHP_VERSION_ID >= 70400) {
-            throw new Warning('PHP 7.4 breaks this test, see https://bugs.php.net/78351.');
-        }
-
         $container = new ContainerBuilder();
         $container->setParameter('other_dir', 'OtherDir');
         $loader = new TestFileLoader($container, new FileLocator(self::$fixturesPath.'/Fixtures'));
@@ -140,12 +138,11 @@ class FileLoaderTest extends TestCase
         );
     }
 
+    /**
+     * @runInSeparateProcess https://github.com/symfony/symfony/issues/32995
+     */
     public function testRegisterClassesWithExcludeAsArray()
     {
-        if (\PHP_VERSION_ID >= 70400) {
-            throw new Warning('PHP 7.4 breaks this test, see https://bugs.php.net/78351.');
-        }
-
         $container = new ContainerBuilder();
         $container->setParameter('sub_dir', 'Sub');
         $loader = new TestFileLoader($container, new FileLocator(self::$fixturesPath.'/Fixtures'));
@@ -163,12 +160,11 @@ class FileLoaderTest extends TestCase
         $this->assertFalse($container->has(DeeperBaz::class));
     }
 
+    /**
+     * @runInSeparateProcess https://github.com/symfony/symfony/issues/32995
+     */
     public function testNestedRegisterClasses()
     {
-        if (\PHP_VERSION_ID >= 70400) {
-            throw new Warning('PHP 7.4 breaks this test, see https://bugs.php.net/78351.');
-        }
-
         $container = new ContainerBuilder();
         $loader = new TestFileLoader($container, new FileLocator(self::$fixturesPath.'/Fixtures'));
 
@@ -195,12 +191,11 @@ class FileLoaderTest extends TestCase
         $this->assertFalse($alias->isPrivate());
     }
 
+    /**
+     * @runInSeparateProcess https://github.com/symfony/symfony/issues/32995
+     */
     public function testMissingParentClass()
     {
-        if (\PHP_VERSION_ID >= 70400) {
-            throw new Warning('PHP 7.4 breaks this test, see https://bugs.php.net/78351.');
-        }
-
         $container = new ContainerBuilder();
         $container->setParameter('bad_classes_dir', 'BadClasses');
         $loader = new TestFileLoader($container, new FileLocator(self::$fixturesPath.'/Fixtures'));
diff --git a/src/Symfony/Component/VarExporter/Tests/VarExporterTest.php b/src/Symfony/Component/VarExporter/Tests/VarExporterTest.php
index a069bcf421..8a70d02be5 100644
--- a/src/Symfony/Component/VarExporter/Tests/VarExporterTest.php
+++ b/src/Symfony/Component/VarExporter/Tests/VarExporterTest.php
@@ -76,9 +76,6 @@ class VarExporterTest extends TestCase
      */
     public function testExport(string $testName, $value, bool $staticValueExpected = false)
     {
-        if (\PHP_VERSION_ID >= 70400 && 'datetime' === $testName) {
-            throw new Warning('PHP 7.4 breaks this test, see https://bugs.php.net/78383.');
-        }
         if (\PHP_VERSION_ID >= 70400 && \in_array($testName, ['spl-object-storage', 'array-object-custom', 'array-iterator', 'array-object', 'final-array-iterator'])) {
             throw new Warning('PHP 7.4 breaks this test.');
         }