Something many people don’t realize is that I didn’t write the original coverage.py. It was written by Gareth Rees in 2001. I’ve been extending and maintaining it since 2004. This ancient history came up this week, so I grabbed the 2001 version from archive.org to keep it here for posterity.

I already had a copy of Gareth’s original page about coverage.py, which now links to my local copy of coverage.py from 2001. BTW: that page is itself a historical artifact now, with the header from this site as it looked when I first copied the page.

The original coverage.py was a single file, so the “coverage.py” name was literal: it was the name of the file. It only had about 350 lines of code, including a few to deal with pre-2.0 Python! Some of those lines remain nearly unchanged to this day, but most of it has been heavily refactored and extended.

Coverage.py now has about 20k lines of Python in about 100 files. The project now has twice the amount of C code as the original file had Python. I guess in almost 20 years a lot can happen!

It’s interesting to see this code again, and to reflect on how far it’s come.