Improve assertions

Author: carusogabriel

Tests/DependencyInjection/FrameworkExtensionTest.php

@@ -1123,7 +1123,7 @@ private function assertCachePoolServiceDefinitionIsCreated(ContainerBuilder $con
         $this->assertFalse($poolDefinition->isAbstract(), sprintf('Service definition "%s" is not abstract.', $id));
 
         $tag = $poolDefinition->getTag('cache.pool');
-        $this->assertTrue(isset($tag[0]['default_lifetime']), 'The default lifetime is stored as an attribute of the "cache.pool" tag.');
+        $this->assertArrayHasKey('default_lifetime', $tag[0], 'The default lifetime is stored as an attribute of the "cache.pool" tag.');
         $this->assertSame($defaultLifetime, $tag[0]['default_lifetime'], 'The default lifetime is stored as an attribute of the "cache.pool" tag.');
 
         $parentDefinition = $poolDefinition;