One team I worked with had tests for the product we made ranging from IE6 to IE11, for example. We did demos in-company where people would poke at the products before launch, play with it. When it reached production, it was rock solid stuff. Our motto was "quality is non-negotiable": we were willing to cut scope but never rush things.

I think things changed since then. "Move fast and break things" was a change, and the bill always comes.