Define Environment

If you need to add something early in the application bootstrapping process (which executed between registering service providers and booting service providers) you could use the defineEnvironment() method:

/**
 * Define environment setup.
 *
 * @param  \Illuminate\Foundation\Application  $app
 * @return void
 */
protected function defineEnvironment($app)
{
    // Setup default database to use sqlite :memory:
    $app['config']->set('database.default', 'testbench');
    $app['config']->set('database.connections.testbench', [
        'driver'   => 'sqlite',
        'database' => ':memory:',
        'prefix'   => '',
    ]);
}

It's an alias to getEnvironmentSetup()

Instead of defineEnvironment(), you can still use predecessor method getEnvironmentSetup().

Using Annotation

You can also use @define-env annotation to customise use of defineEnvironment() for specific test.

protected function usesMySqlConnection($app) 
{
    $app->config->set('database.default', 'mysql');
}

protected function usesSqliteConnection($app)
{
    $app->config->set('database.default', 'sqlite');
}

/**
 * @test
 * @define-env usesMySqlConnection
 */
public function it_can_be_connected_with_mysql()
{
    // write your tests
}

/**
 * @test
 * @define-env usesSqliteConnection
 */
public function it_can_be_connected_with_sqlite()
{
    // write your tests
}