Windows being used to make Macs? is not a big deal

We all know that Apple makes Mac computers but using rival operating system Microsoft Windows to do so appears to be a big surprise for many of the tech company's avid fans. Yeah but software developers and engineers uses several OS for testing. So what's the big deal? 
Macs running what appeared to be Windows XP or 7 were shown in a photo tweeted by no less than Apple CEO Tim Cook over weekend.

Watching the Mac Pro come together in Austin yesterday,thanks to a team loaded with American manufacturing expertise.


It all began late Friday, June 6, with what at first seemed to be an innocuous tweet by Cook of Apple's Mac Pro assembly line:

Well Tech companies need each other like Google uses the iPhone, iPad and Windows to test its apps, and Cook’s tweet is thus "not really a slip up, but rather an admission (albeit inadvertent) that Apple is well part of this coterie, and not an island.".