An apparatus, system, and method are provided for facilitating port testing of a multi-port host adapter. The present invention includes a scheduler that schedules execution of a plurality of threads to test a first port and a plurality of threads to test a second port of a multi-port adapter. The port test routine is divided into threads such that execution time and switching overhead is minimized. A multithreading module provides multithreaded execution of the plurality of threads such that the port test of the first port and the port test of the second port are performed in parallel. The apparatus further includes a communication module that takes the first port and the second port off-line. A third port remains on-line for Input/Output (I/O) communications that are multithreaded with the plurality of threads involving the first port and the second port.