Easily test your Laravel middleware classes. Blog post: http://blog.stidges.com/post/testing-your-laravel-middleware

TestCase.php

<?php

namespace Tests;

use Illuminate\Foundation\Testing\TestResponse;
use Illuminate\Foundation\Testing\TestCase as BaseTestCase;
use PHPUnit\Framework\Assert;

abstract class TestCase extends BaseTestCase
{
    use CreatesApplication;
    
    /**
     * Setup the test environment.
     *
     * @return void
     */
    protected function setUp()
    {
        parent::setUp();

        TestResponse::macro('assertMiddlewarePassed', function () {
            Assert::assertEquals('__passed__', $this->content());
        });
    }

    /**
     * Call the given middleware.
     *
     * @param  string|string[]  $middleware
     * @param  string  $method
     * @param  array  $data
     * @return \Illuminate\Foundation\Testing\TestResponse
     */
    protected function callMiddleware($middleware, $method = 'GET', array $data = [])
    {
        return $this->call(
            $method, $this->makeMiddlewareRoute($method, $middleware), $data
        );
    }

    /**
     * Call the given middleware using a JSON request.
     *
     * @param  string|string[]  $middleware
     * @param  string  $method
     * @param  array  $data
     * @return \Illuminate\Foundation\Testing\TestResponse
     */
    protected function callMiddlewareJson($middleware, $method = 'GET', array $data = [])
    {
        return $this->json(
            $method, $this->makeMiddlewareRoute($method, $middleware), $data
        );
    }

    /**
     * Make a dummy route with the given middleware applied.
     *
     * @param  string  $method
     * @param  string|string[]  $middleware
     * @return string
     */
    protected function makeMiddlewareRoute($method, $middleware)
    {
        $method = strtolower($method);

        return $this->app->make('router')->{$method}('/__middleware__', [
            'middleware' => $middleware, 
            function () {
                return '__passed__';
            }
        ])->uri();
    }
}