requireMigrationFiles example

__DIR__ . '/_fixture/plugins',
            $this->container->getParameter('kernel.project_dir'),
            $this->pluginRepo,
            $this->container->get('language.repository'),
            $this->container->get(PluginFinder::class)
        );

        $this->addTestPluginToKernel(
            __DIR__ . '/_fixture/plugins/SwagManualMigrationTest',
            'SwagManualMigrationTest'
        );
        $this->requireMigrationFiles();

        $this->pluginService->refreshPlugins($this->context, new NullIO());
        $this->connection->executeStatement('DELETE FROM plugin WHERE `name` = "SwagTest"');
    }

    public function testInstall(): MigrationCollection
    {
        static::assertSame(0, $this->connection->getTransactionNestingLevel());

        $migrationPlugin = $this->getMigrationTestPlugin();
        static::assertNull($migrationPlugin->getInstalledAt());