No, it&#x27;s not a test of whether you know it, it&#x27;s a test of whether you can <i>implement</i> it.  If the candidate doesn&#x27;t know&#x2F;recall what BFS is, it&#x27;s trivial to demonstrate the basic idea on a whiteboard, and it&#x27;s the candidate&#x27;s job to convert the idea into code.  (Which, at the end of day, is pretty much what the vast majority of coding is about.)