On an entry level for a codebase you are not familiar with, how do you introduce testing, an at what levels ?
When introduced to codebases with no tests at all and at the same time being tangled together, it's difficult to measure where it's best to put in the energy.
I often pick a smaller corner to start from but in messy codebases that corner often grows bigger the more I dig into that initial corner. So all of a sudden I have my hands full and from a small corner I find myself refactoring a lot more than I set out to. Which is not a bad idea but I was wondering if I could use another strategy.
I also have a hard time writing tests for something I know I will change over short time, but is this a valid argument ? Is there a sweet spot for when to introducing tests into a messy codebase ?
Thanks a lot!