Hey package authors and contributors:
Keep in mind, many people are potentially relying on your packages for mission-critical applications. When you make updates, please test in multiple browsers, and in Internet Explorer—not necessarily version 9 or below, but absolutely version 10 and up.
Microsoft offers free virtual machines of Windows running IE 6 through 11, so there’s no excuse. 
Thank you.
I do agree with you that packages should be tested extensively on all fronts. Testing client side functionality against targeted browsers is definitely a must for a high quality package.
That being said, in an open source ecosystem, that’s also your job as a developer who relies on a package for mission critical apps.
The authors already does have a lot on their plates and they’re mostly investing their own personal time. So the way to contribute back and say thank you is test, report, collaborate with the author for a solution, or even better yet provide a pull request.
Of course! And if I hadn’t double-checked and tested myself, I would’ve promoted a totally failing build to production. 
For all the jokes on Microsoft, I wish Apple would do the same. Someone reported a bug that only happened on iPhone (even IE8 was fine). Since I don’t have an iPhone or Mac, I had no way to test it other than asking a friend for an iPhone.
AFAIK, the only/best way would be to run a Hackintosh on Windows, install Xcode on it, then run the iOS Simulator.
I tried that but the stars weren’t aligned. I gave up after a couple of hours of installing and reinstalling OSX on VirtualBox. The last straw for me was when I managed to run an image of Mountain Lion without errors but when I tried to install XCode it said I needed to upgrade the OS before using it.
Ahh, I didn’t know you could install a virtual OS X on Windows. You may want to try VMware Fusion Pro. VirtualBox was being buggy for me, so I decided to ditch it and picked up Fusion Pro. Well worth the money. (not 100% sure VMware Windows can run OS X guests, but the Mac version can)
I won’t try again unless someone comes up with turn key VM, like Microsoft offers for testing on Windows. In the meantime iPhone users should do the testing on their platform like serkandurusoy suggests.
The default inclusion of es5-shims with Meteor 1.2 will also reduce problems with differences in JavaScript APIs. Using autoprefix for CSS deals with CSS differences. So having those two tools in place should take care of most potential issues that are caused by browser differences in modern browsers (excluding old versions).
Microsoft have http://dev.modern.ie/tools/screenshots/
which covers a lot of devices including apple
Unfortunately it doesn’t let you use your website so it’s more to check if the design is working or not. It might well be that your site does render okay on a device but when you click a button it doesn’t work as expected.