A system and method to test a host bus adapter's ("HBAs") ability to handle stream of invalid characters is provided. A data presenter module presents data to a HBA without being aware of a data format. A data producer module that is aware of the data format and schedules special characters so that the HBA can perform alignment operations. A bit offset change module changes a bit offset that is used by the data presenter module and causes to send random serial data to the HBA, which results in loss of alignment in the HBA and causes the HBA to decode invalid characters.