A Software Library with No Code by Drew Breunig

the whenwords library contains no code. Instead, whenwords contains specs and tests, specifically:

• SPEC.md: A detailed description of how the library should behave and how it should be implemented.
• tests.yaml: A list of language-agnostic test cases, defined as input/output pairs, that any implementation must pass.
• INSTALL.md: Instructions for building whenwords, for you, the human.

Drew goes on to list a bunch of scenarios when this will not be useful. But it’s an interesting way to look at libraries.