Inline snapshots

[aszenz]

Inline snapshots are a way to create a snapshot of the output when running an expression in a test.

It's similar to snapshot testing but the expected output is stored inline within the source.

It requires phpunit to modify the test program to add the output.

See:
https://jestjs.io/docs/snapshot-testing#inline-snapshots

[sebastianbergmann]

This is outside the scope of this project.