I regret that this post is the top of the page. I failed to anticipate that people will take any opportunity to have yet another boring static typing debate.
But to be clear, in my day job I work on an app with 350k lines of Python in it and the reason I know it mostly works is due to our test coverage. As someone else mentioned in this thread, a lack of tests should not give you confidence regardless of the language.
"There is no roadmap. I mostly implement the stuff which I need or interests me, or which gives me the opportunity to learn."
Pretty much says it all. Seems it was primarily written to satisfy personal needs, not be the end-all, be-all of professionally written software. It is, incidentally, potentially interesting to others who might want to learn from it, or use it, knowing the background.
So, you might cut the guy a break. The requirements for personal projects aren't the same.
But to be clear, in my day job I work on an app with 350k lines of Python in it and the reason I know it mostly works is due to our test coverage. As someone else mentioned in this thread, a lack of tests should not give you confidence regardless of the language.