I think in this context it boils down to the email client supporting media queries. Testing should be fairly easy - set up a media query in the head with specific styles applied to a reliably rendering element, check to see if those styles are applied. Unfortunately, support for media queries is lacking in a lot of email clients.
Jason Rodriguez
@rodriguezcommaj
rodriguezcommaj.com
modernhtmlemail.com
From: Charles McCathie Nevile Charles McCathie Nevile
Reply: Charles McCathie Nevile chaals@yandex-team.ru
Date: February 6, 2014 at 12:46:02 PM
To: Stig Morten Myre stigm@campaignmonitor.com
Subject: Campaign Monitor compatibility chart
Hi,
I'm trying to use it as a starting point for a compatibility table. But I
am wondering what "Responsive" really means…
(and what a test for that looks like)
cheers
Chaals
--
Charles McCathie Nevile - Consultant (web standards) CTO Office, Yandex
chaals@yandex-team.ru Find more at http://yandex.com