Ideally, commenting out any part of your code will produce a test failure. Mutation testing works on this principle.
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What are the most interesting upcoming scripting languages? Scripting remains an important part of the programming language ecosystem.
Optimise time to first feature. Allow mutation of the running system to experiment. Interactive inspection of data.
"Example Driven Development" using Glamorous and Pharo Smalltalk: https://medium.com/feenk/an-example-of-example-driven-development-4dea0d995920
Tests returning values and composing is a really interesting model. It establishes structure and shows which test failure is the most 'fundamental'.
I'm increasingly doubtful that commit messages should be entirely immutable.
I sometimes find myself editing or commenting on merged pull requests, to help future readers.
Phabricator appended a URL to commit messages, which helped. In principle PR merging could do the same thing.