Laravel5, PHPUnit and Date Mutators: can't use mutator in data provider

I've just noticed that we can't use date mutators in a test data provider. Example

class FooTest extends TestCase {

    /**
     * @dataProvider baz
     */
    public function testBar($baz) {
        $this->assertTrue(true);
    }

    public function baz() {
        $model = new Foo(['someDate' => \Carbon\Carbon::now());
        return [
            [$model]
        ];
    }
}

Given your model like this

class Foo extends Model {

    public function getDates() {
        return ['someDate'];
    }

}

That test will produce the following error

PHP Fatal error:  Call to a member function connection() on null in /var/www/agents/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Model.php on line 3224

That's because in eloquent Model we have

protected function getDateFormat()
{
    return $this->dateFormat ?: $this->getConnection()->getQueryGrammar()->getDateFormat();
}

which is trying to access the connection that is not established in the test data provider.

So, how should we provide that testBar() method an input model?

via Chebli Mohamed