Though I was primarily a SYSOP for our internal mini mainframe, I also coded for other sections. To do so we connected using dumb terminals via 300baud to a Boeing datacenter and paid for connection as well as processor time. While it was government work, Reagan was just starting to take money away from the agencies, so we were encouraged to compile and run as little as possible.
Meanwhile, by 1983 there were a couple of COBOL packages for the Atari 800, a machine I happened to have at home. So I'd code on that, allowing me to compile, link, and execute, all in real time!! Every bit of my submitted code was fully tested. The downside was that I had to print it out and then type it back into those fucking dumb terminals where the occasional typo might slip in.
Prior to that I had the misfortune of batch programming on punchcards, dropping off decks of cards to pick up a day or two later with greenbar printouts full of the most obnoxious fatal errors.