Update the `TestCompiler` so that classes can be defined using
a `Lookup`. This update allows package-private classes to be
accessed without needing a quite so unusual classloader setup.
The `@CompileWithTargetClassAccess` should be added to any
test that needs to use `Lookup` based defines. The test will
run with a completed forked classloader so not to pollute the
main classloader.
This commit also adds some useful additional APIs.
See gh-28120
Add a new unpublished `spring-core-test` module to support testing of
generated code. The module include a `TestCompiler` class which can be
used to dynamically compile generated Java code. It also include an
AssertJ friendly `SourceFile` class which uses qdox to provide targeted
assertions on specific parts of a generated source file.
See gh-28120
