src/Neutrino/Support/Facades/Facade.php
protected static function isMock()
    {
        $name = static::getFacadeAccessor();

        return isset(self::$resolvedInstance[$name]) && self::$resolvedInstance[$name] instanceof MockInterface;
    }
protected static function isMock()
    {
        $name = static::getFacadeAccessor();

        return isset(self::$resolvedInstance[$name]) && self::$resolvedInstance[$name] instanceof MockInterface;
    }
Determines whether a mock is set as the instance of the facade.

@return bool