Outdated integration test?

[StudioMaX]

Hey!
I've tries to fix a few deprecations with MicroKernelTrait in my code after updating to Symfony 5.1 and tried to see how this was fixed in custom bundles.
Look here:

webpack-encore-bundle/tests/IntegrationTest.php

Lines 267 to 281 in 5c0f659

	if (method_exists(AbstractWebpackEncoreIntegrationTestKernel::class, 'configureRouting')) {
	class WebpackEncoreIntegrationTestKernel extends AbstractWebpackEncoreIntegrationTestKernel {
	protected function configureRouting(RoutingConfigurator $routes): void
	{
	$routes->add('/foo', 'kernel:'.(parent::VERSION_ID >= 40100 ? ':' : '').'renderFoo');
	}
	}
	} else {
	class WebpackEncoreIntegrationTestKernel extends AbstractWebpackEncoreIntegrationTestKernel {
	protected function configureRoutes(RouteCollectionBuilder $routes)
	{
	$routes->add('/foo', 'kernel:'.(parent::VERSION_ID >= 40100 ? ':' : '').'renderFoo');
	}
	}
	}

configureRouting(RoutingConfigurator $routes) will be implemented when configureRouting will exist, or configureRoutes(RouteCollectionBuilder $routes) when it does not exist.

Looks like this configureRouting was implemented here (probably in some of 5.1-dev), but then it was reverted here (when Symfony 5.1 was released).

So, configureRouting will never actually exist, and method configureRoutes(RouteCollectionBuilder $routes) will always be implemented.

But RouteCollectionBuilder was deprecated since 5.1 and we must use some sort of

if (^5.1) {
    protected function configureRoutes(RoutingConfigurator $routes): void { ... }
} else {
    protected function configureRoutes(RouteCollectionBuilder $routes) { ... }
}

We cannot simply omit the type declaration (protected function configureRoutes($routes)), as it is checked by the BC layer:
https://github.com/symfony/symfony/blob/e5b5d9ea14ef8141c20b79bbeaae360f1afbdc55/src/Symfony/Bundle/FrameworkBundle/Kernel/MicroKernelTrait.php#L168-L174

Do you have any ideas how to check this without using version comparison?