firefly-iii/tests/TestCase.php

<?php
/**
 * Class TestCase
 */
class TestCase extends Illuminate\Foundation\Testing\TestCase
{

    /**
     * Creates the application.
     *
     * @return \Illuminate\Foundation\Application
     */
    public function createApplication()
    {
        $app = require __DIR__ . '/../bootstrap/app.php';

        $app->make('Illuminate\Contracts\Console\Kernel')->bootstrap();

        return $app;
    }

    /**
     * @param string $class
     *
     * @return mixed
     */
    public function mock($class)
    {
        $mock = Mockery::mock($class);

        $this->app->instance($class, $mock);

        return $mock;
    }

}