Having high quality, reusable test suites for common patterns and operations will make it easier to replace tools with a better version.
My inspiration for this is WPT.
I think there are two main benefits :
authors of tools can win a lot of time by not having to write all the tests and do all the investigations for high quality test corpora.
users of tools can compare two similar tools and check how they both score against the same test suite.
Authors of tools can still choose to deviate and fail specific test cases.
It might make sense in their context to optimize specific things and fail others.
When writing the tokenizer for csstools I was surprised that there weren't any test suites I could adopt to verify my work.
To help others I created https://github.com/romainmenke/css-tokenizer-tests
I never advertised this, but it still seemed to work as this test suite was adopted by https://github.com/keithamus/csslex
Having high quality, reusable test suites for common patterns and operations will make it easier to replace tools with a better version.
My inspiration for this is WPT.
I think there are two main benefits :
Authors of tools can still choose to deviate and fail specific test cases.
It might make sense in their context to optimize specific things and fail others.