ThrowingExtension example

$this->expectExceptionMessage('Using a cast in "env(int:FOO)" is incompatible with resolution at compile time in "Symfony\Component\DependencyInjection\Tests\Compiler\BarExtension". The logic in the extension should be moved to a compiler pass, or an env parameter with no cast should be used instead.');
        $container = new ContainerBuilder();
        $container->registerExtension(new BarExtension());
        $container->prependExtensionConfig('bar', []);

        (new MergeExtensionConfigurationPass())->process($container);
    }

    public function testThrowingExtensionsGetMergedBag()
    {
        $container = new ContainerBuilder();
        $container->registerExtension(new ThrowingExtension());
        $container->prependExtensionConfig('throwing', ['bar' => '%env(FOO)%']);

        try {
            $pass = new MergeExtensionConfigurationPass();
            $pass->process($container);
            $this->fail('An exception should have been thrown.');
        } catch (\Exception $e) {
        }

        $this->assertSame(['FOO'], array_keys($container->getParameterBag()->getEnvPlaceholders()));
    }