The upstream build.gradle contains the invocation useJUnitPlatform() for the
tests, which is for JUnit5. Yet this is not understood by the current
gradle--junit5 couple in Debian, so I switched to JUnit4 and had to change the
annotations, add some "public" keywords... and I patched build.gradle
accordingly.

As further versions of JUnit5 (and gradle?) will get packaged, one should try again to run the unpatched files.

 -- Pierre Gruet <pgt@debian.org>  Sat, 15 May 2021 07:20:13 +0200
