Hey everyone, a while ago we (thanks to many contributors that helped here) started migrating tests from JUnit4 to JUnit5. While most things are straightforward to migrate, parameterized tests are not.
JUnit5 doesn't support parameterization at the class level yet <https://github.com/junit-team/junit5/issues/878>, which makes it difficult to migrate existing parameterized tests to JUnit5. There are a few possible options and I'd like to see what the community thinks here: 1) When migrating to JUnit5, parameterized testing is moved to every test method, meaning that every test method would have a *@ParameterizedTest* and a *@ValueSource/@MethodSource *annotation. This is the official JUnit5 approach that is recommended. However, it is quite repetitive, as every single test method now needs to define its own parameters. One example of this approach can be seen in #9185 <https://github.com/apache/iceberg/pull/9185>, where *TestFlinkScan* is migrated to JUnit5. 2) We could introduce a similar approach that the Flink community did with https://issues.apache.org/jira/browse/FLINK-25315 / apache/flink#20145 <https://github.com/apache/flink/pull/20145>. This would introduce a custom *ParameterizedTestExtension* with two additional *@Parameter / **@Parameters* annotations to mimic the same behavior that JUnit4 provided. One example of this approach can be seen in #9161 <https://github.com/apache/iceberg/pull/9161>, where *TestDictionaryRowGroupFilter* is migrated to use this way of parameterized testing. I guess another option would be to wait until this is properly supported by JUnit5, but it is unclear when that will be. Eduard
