test: autoExtension unit test

[Timeless0911]

Summary

Related Links

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

[fi3ework]

Do we need to move fixtures to the root dir from core package? If it's only used by core packages, I think its' good to leave it there.

[Timeless0911]

Do we need to move fixtures to the root dir from core package? If it's only used by core packages, I think its' good to leave it there.

It is only used do some unit test for some core functions in core package, so just leave it here. If we need to add global fixtures, we can add them to e2e folder instead.

For autoExtension case, in e2e test, we check the build artifacts to see if the correct file is generated and in unit tests in core package, we just need to check the return value of getDefaultExtension funtion.

[fi3ework]

Sorry, my mistake. I thought this PR moved to the project root dir (the tree indent is too inconspicuous). LGTM.