I know most test-runners have the capability to run specific test which suggest that any editor that is capable of executing command-line and bind it to something can support my workflow with some annoyance here and there (as you mentioned, your setup isn't as magical as my description ;)). I mean... someone could've written shell scripts that help them run a bunch of things too...
This is akin of the discussion of using ctags and the need to detect file changes and re-run ctags. Last time I google it there were plenty plugins for each editors and ways to set it up (except there's no clear winner ;)).
The whole idea here is that the IDE helps you not to worry about any of that. IntelliJ supports multiple (mainstream) languages that fulfill my workflow nicely.
Good point that I'm sure Emacs can handle way more languages but the steps to set it up and the limitation (filename change? method name change?) feels more static than dynamic to me.