Customize HTTP header in Lumen unit test

CustomHeaderRequestTrait.php

<?php

use Illuminate\Testing\TestResponse;
use Symfony\Component\HttpFoundation\Request as SymfonyRequest;

trait ApiTokenRequestTrait
{
    public function call($method, $uri, $parameters = [], $cookies = [], $files = [], $server = [], $content = null, $headers = [])
    {
        $symfonyRequest = SymfonyRequest::create(
            $uri,
            $method,
            $parameters,
            $cookies,
            $files,
            $server,
            $content
        );
        foreach ($headers as $key => $value) {
            $symfonyRequest->headers->set($key, $value);
        }
        $this->app['request'] = \Laravel\Lumen\Http\Request::createFromBase($symfonyRequest);
        return TestResponse::fromBaseResponse(
            $this->app->prepareResponse($this->app->handle($this->app['request']))
        );
    }
}