Only one test will pass at a time (5.1)

I tried to post this a bit ago but I think the original post got lost in the nether thanks to some pasted smart quotes. If this is a double-post I do apologize.

I'm making a point to work on testing early on with a new project, but having a pretty rough time.

If I run either one of the tests below on their own, it will pass. However, when I attempt to run both tests, I am greeted with:

exception 'ErrorException' with message 'Undefined variable: errors’ in <compiled template path>

The views have some basic validation error rendering using this method: {{$errors->first('email')}}

<?php

class AuthTest extends TestCase {

    function __construct()
    {
        parent::setUp();
    }

    protected $baseUrl = "http://portal.dev";

    public function testUserRegistration()
    {
        $this->visit('/register')
             ->type('valid@email.com', 'email')
             ->press('Register')
             ->seePageIs('/login')
             ->see('The supplied email is already in the system. Login?');
    }

    public function testUserLogin()
    {
        $this->visit('/login')
                 ->seePageIs('/login')
                 ->type('valid@email.com', 'email')
                 ->type('goodpass', 'password')
                 ->press('Sign-In')
                 ->seePageIs('/dashboard'));
    }

}

It would appear something is going haywire with middleware and/or sessions, but I'm quite a bit green when it comes to phpunit, let alone testing Laravel.

Any guidance or clues are appreciated. Thanks!