tests are included in npm release.

[Raynos]

The tests are tiny, its ok to include them.

It means cd node_modules/memoize && npm i && npm t works.

It means npm test memoize works.

This is a useful feature of npm.

[medikoo]

As @Raynos mentioned, it's expected and intended. Developers need to be able to test the package they want to use.