Test fixes for build_test 3.0.0

[davidmorgan]

For builder package maintainers.

When you use build_runner 2.5.0 you'll also need to update to build_test 3.0.0, which has breaking change.

Sorry about that! build_test depends a lot on build_runner internals, so it was not possible to keep it working exactly the same through the huge internal refactor. Hopefully, some of the changes are improvements :)

See the changelog.

Here are some example fixes:

built_value: google/built_value.dart#1367
source_gen: dart-lang/source_gen#761

Any questions, or if any changes could help smooth the transition, I'll be happy to help :)

FAQ

Why is my test no longer reading real sources on disk?

This no longer happens automatically, for testBuilder the way to do it is

final readerWriter = TestReaderWriter();
await readerWriter.loadIsolateSources();
testBuilder(
  yourBuilder,
  {} /* test assets here */,
  readerWriter: readerWriter,
);

and for resolveSources, pass nonInputsToReadFromFilesystem to read specific additional files. I have a work-in-progress PR adding a way to read all the files as before here.

Other Notes

The testBuilder generateFor parameter now restricts the set of visible sources, not just the set of input sources; this is broken, if someone needs it to work please let me know and I'll fix it. However, the defaults are now much closer to a real build, so please first try removing generateFor altogether, like I do in the source_gen PR above.