Email test case for testing emails with Mailtrap.io in Phpunit

EmailExampleTest.php

<?php
/*
|--------------------------------------------------------------------------
| EmailExampleTest
|--------------------------------------------------------------------------
|
| Email test case for testing emails with Mailtrap.io in Phpunit
|
| Requirements: 
| - Laravel 5.1
| - Guzzle
| - Faker
| - Mailtrap
|
| Inspired by that awesome gist: https://gist.github.com/DavertMik/7969053
|
*/


use Illuminate\Foundation\Testing\WithoutMiddleware;
use Illuminate\Foundation\Testing\DatabaseMigrations;
use Illuminate\Foundation\Testing\DatabaseTransactions;

use Faker\Factory as Faker;

use GuzzleHttp\Client;

class EmailExampleTest extends TestCase
{

    public function setUp()
    {

      parent::setUp();

      // Create connection mailtrap.io
      $this->mailtrap = new Client([
            'base_uri' => getenv('MAILTRAP_API_BASE_URI'),
            'headers' => [
                'Api-Token' => getenv('MAILTRAP_API_TOKEN')
            ]
        ]);

      $this->mailtrap_inbox = getenv('MAILTRAP_API_INBOX');

      // Clean messages of mailtrap between each tests
      $this->cleanMessages();

      // Faker
      $this->faker = Faker::create();

    }

    public function test_it_send_contact_email()
    {  

        $this->visit('/contact')
            ->type($this->faker->email, 'email')
            ->type($this->faker->paragraph(50), 'message')
            ->press('contact us')
            ->seePageIs('/contact')
            ->see('alert --success');

        // Check if email sent (here it's where the magic happens)
        $this->assertEmailIsSent('Email didn\'t send');

    }

    /*
    |--------------------------------------------------------------------------
    | Super simple mailtrap API used in new asserts created
    |--------------------------------------------------------------------------
    |
    */

    /**
     * Fetch messages of the mailtrap inbox
     * @return json The messages of the inbox given
     */
    private function getMessages()
    {
        $response = $this->mailtrap->request('GET', "inboxes/$this->mailtrap_inbox/messages");
        return json_decode((string) $response->getBody());
    }

    /**
     * Fetch the last message received in mailtrap inbox
     * @return object Message
     */
    private function getLastMessage()
    {
        $messages = $this->getMessages();

        if (empty($messages))
        {
            $this->fail('Api Mailtrap: No messages found.');
        }

        return $messages[0];
    }

    /**
     * Clean Messages of the mailtrap inbox
     * @return void
     */
    private function cleanMessages()
    {
        $response = $this->mailtrap->request('PATCH', "inboxes/$this->mailtrap_inbox/clean");
    }

    /*
    |--------------------------------------------------------------------------
    | Asserts for mails (mailtrap)
    |--------------------------------------------------------------------------
    |
    */
    public function assertEmailIsSent($description = '')
    {
        $this->assertNotEmpty($this->getMessages(), $description);
    }

    /**
     * Write here your awesome assert .....
     *
     * you can find inspiration assert here: https://gist.github.com/DavertMik/7969053
     */
   
}

One does not simply access the env values directly - you have to do this via config(); method .