Question about test score

[Farenheith]

Hello!

The team I work on right now maintains a package called @codibre/fluent-iterable (analysis here: https://api.npms.io/v2/package/%40codibre%2Ffluent-iterable and our GitHub link https://github.com/Codibre/fluent-iterable/).
We have pretty good coverage and unit tests overall, as far as we know, but the score for tests is only 0.6
Could you give us some guidance on how we can do better with that score?

Reading the documentation, I couldn't see what we're missing on that specific indicator, as all those questions we have satisfactory answers: Has tests? What's their coverage %? Is the build passing?

Thank you!