Previously, spring-webmvc and spring-webflux both contained tests
that would create gzipped files, write them to the filesystem
alongside the project's compiled test classes, and configure them to
be deleted on JVM exit. The output location placed the files on the
classpath, polluting it for every subsequent test that used the same
ClassLoader. The test-sources plugin combined with Gradle's use of
worker JVMs, broadens the scope of this pollution to other, downstream
projects in the same build. For example, the tests for
spring-websocket will have a different classpath depending on whether
or not the tests for spring-webmvc have already been run on the same
worker as part of the current build.
This commit updates the spring-webmvc and spring-webflux modules to
introduce a new JUnit Jupiter extension, GzipSupport. This extension
allows gzipped files to be created via an injectable GzippedFiles
class and automatically deletes each created file in an after-each
callback. This ensures that a gzipped file only exists on the
classpath for the duration of the test that needs it, avoiding the
pollution of the classpath of any subsequent tests.
Closes gh-23970
f7bc8c8268