no hiring manager would ever give you this feedback. I call BS.
The funny thing is, casual clothes often take more thought. With a suit you can blend in, with casual clothes, even if they're not great, they're /yours/; no hiding from your choices. Sure you can screw up a suit too, but it takes a lot more trying. As long as it fits well and it's not weird, it's a suit. There's not a lot to think about. It's basically like the classical Jobs' uniform of jeans+turtle neck, but way better looking. Unfortunately it now has the stigma of being "stuffy".
In Sydney, I find it impossible not to see the suit and tie as an arbitrary cultural hold-over from a different climate.
The suit causes the company to waste thousands of dollars on air-conditioning, and introduces a gendered Cold War, because we simultaneously make the female staff wear clothes that strike a delicate balance between professional and attractive.
The suit is so impractical and stupid in this climate that it's hard not to think negatively about an office culture that demands it, or those who haven't questioned its place as a status symbol.
All of our suburbs have peaked, ceramic tiled roofs. That design makes perfect sense when you have regular snowfall, which you need to run off the roof.
Here, a slightly sloping concrete roof would be a pleasant roof-top garden, or a more easily accessible place to put a solar-powered hot water tank.
The tiled roofs are expensive, costly when they're damaged by our frequent, heavy hale, and a good place for possums to get trapped and die.
All because our architects regularly pretend we're in England.
Suits are admired because they developed from the dress of the aristocracy and military and represent established wealth and power. They are a clumsy design, full of anachronisms, for example the buttons on the cuffs of a suit coat originate from Napoleon trying to stop soldiers from wiping their noses on their clothes. The second pocket on the right of many jackets is a ticket pocket introduced to hold an English gentleman's railway ticket in the time when rail was an exclusive way to travel.
If they really represented an evolved ideal way to make the human body look 'good' we'd all love to wear them and this debate wouldn't be happening.
This is correct IMO, because in my experience when I wear a suit or a tuxedo I feel sort of superior to others around me. This could have something to do with my personality or with the images that I have been fed or both. The idea has been implanted that "suits" == "good jobs" and "good jobs" == "good money" or "suits" == "obedience" and "obendience" == "climbing the success ladder". When I wear my black sweatshirt everyday to my engineering job, I wear it for comfort and it in no way make me look or feel inferior to other people.
Obviously this wasn't because the suit made my body look great.
If you do it at an interview or something, you'll get a lot of people questioning your competence and fit.
I've also interviewed many people wearing a wide variety of clothing, and no one cares about that either. If we judged interviews based on what people wore, drove, ate, etc. we'd never get any competent engineers. A good culture fit means they interested in technology and our product, not that they fit some (in my experience false) stereotype.
As for your test, if there is a big change in how you dress (in any way) after people know you, it will garner notice.
I think you'd find that an amicable suit-wearing programmer could easily do well at an interview.