使用Laravel5.5的Testing做api测试的时候，发现无论怎么设置请求的都是本地的url。查看源码发现

vendor/laravel/framework/src/Illuminate/Foundation/Testing/Concerns/MakesHttpRequests.php

文件下有段代码

/**
 * Call the given URI and return the Response.
 *
 * @param  string  $method
 * @param  string  $uri
 * @param  array  $parameters
 * @param  array  $cookies
 * @param  array  $files
 * @param  array  $server
 * @param  string  $content
 * @return \Illuminate\Foundation\Testing\TestResponse
 */
public function call($method, $uri, $parameters = [], $cookies = [], $files = [], $server = [], $content = null)
{
    $kernel = $this->app->make(HttpKernel::class);

    $files = array_merge($files, $this->extractFilesFromDataArray($parameters));

    $symfonyRequest = SymfonyRequest::create(
        $this->prepareUrlForRequest($uri), $method, $parameters,
        $cookies, $files, array_replace($this->serverVariables, $server), $content
    );

    $response = $kernel->handle(
        $request = Request::createFromBase($symfonyRequest)
    );

    if ($this->followRedirects) {
        $response = $this->followRedirects($response);
    }

    $kernel->terminate($request, $response);

    return $this->createTestResponse($response);
}

其中

$response = $kernel->handle(
        $request = Request::createFromBase($symfonyRequest)
    );

我猜测laravel根本没有发送远程请求，而是直接构造$requset灌入kernel执行，没有发起http请求就意味着没有经过nginx，apache之类的web服务器。这样的测试跟实际生产环境有相当差异。

PS: PHP发起http请求几种方式

file_get_contents
curl
fsocket
GuzzleHttp

没有查到$kernel->handle($request);之后有执行远程请求的