Saw that testing type came up in a couple threads. I’m working on a design tool that lets you test fonts (either yours, or from other providers) in the browser responsively and save out HTML samples/specimens. It basically lets you get the important things down quickly with an eye towards responsive type.
That said, i’m working on it completely independently so any feedback would be much appreciated, just shoot me an email! http://typeshiftapp.com/
Typeshift stays as out of the way as possible so you can quickly see relationships between typefaces, flexible widths, and viewport units in the same way text is set on the web:
Here i’m matching Founders Grotesk with Yrsa set in viewport width units. From there I can export as many lockups as I want to test on different browsers or hide the panels and resize the browser window to see how things work responsively.
(Edit:) Again built this on my own over the past several months so would love to hear people’s thoughts – definitely not fully baked.