@hamje32 - I think testing is the most important part of any engineering process, whether you’re talking about hardware engineering or software engineering.
Intel has had its share of fiascos with computer chips that had faults in them; millions of dollars worth of computers and components had to be recalled as a result.
Of course testing the CPU is something that involves a team of engineers I would suppose, not simply one individual. I am sure that they have advanced software testing tools, and strangely enough, there is very little room for error too.
Sometimes a chip will produce an error if it encounters a rare equation that, statistically, it may stumble upon once every 200 years. So you’d think it wouldn’t be a big deal; but even then, the chip manufacturer will issue a recall.