This new script contains reusable logic extracted from
`integration-tests/checkstyle.sh`, facilitating the introduction of additional
integration tests.
Summary of changes:
- Update the set of expected changes for compatibility with the latest
features, except for the `ErrorProneRuntimeClasspath` check.
- Test against version 10.12.7 rather than 10.13.0.
- Omit the targeted tag from file names, so that similar upgrade PRs can be
tested using an `/integration-test` GitHub comment.
The new `integration-tests/checkstyle-10.12.4.sh` script can be executed
locally or by adding a comment containing the string `/integration-test`
to a pull request.
The integration test comprises a shell script that:
1. Checks out a Checkstyle release tag.
2. Applies a small patch to enable Error Prone Support.
3. Runs the build in Error Prone patch mode, until no further changes
are applied.
4. Validates that:
- The build (including tests) still passes.
- The set of changes matches a pre-recorded diff.
- The set of Error Prone Support-emitted warnings matches a
pre-recorded list.
The script also has a `--sync` mode using which the expected diff and
warnings can be updated. Combined, the script makes it easy to assess
and track the impact of changes to Error Prone Support in relation to
the Checkstyle code base.
Over time this setup will be generalized to include integration tests
against other code bases.
