Now that we're going for Java 5, I took some time this evening to poke at using Junit4. I've done enough for proof of concept (POC), but before going further I wondered if there's enough interest or cautions or objections.
It's actually not bad. I was afraid that we'd have to do an "all or none" conversion, but Junit3 and Junit4 co-exist quite happily both in IntelliJ and in ant. I managed to get all of the tests in ...test/org/apache/lucene/search/function to run under junit4, while all the rest of the tests are running under Junit3.... The short form is that I made a copy of LuceneTestCase called LuceneTestCaseJ4 that does NOT derive from TestCase but preserves (almost) all of the other functionality. There's some pesky nonsense with the constructor that takes a parameter (apparently disallowed by Junit4, and for POC I'm not going to worry about it, I'm not sure this is anything more than an artifact of Junit3 and can be removed). From there, it was just a matter of making the relevant test cases inherit from LuceneTestCaseJ4 and resolving some visibility issues (e.g. the setup and teardown (i.e. @Before and @After) in LTCJ4 had to be public), and resolving imports. I had to hack the common-build.xml a bit (warning, I'm no Ant expert) to include both junit jars, but that seems to work fine. So I *claim* that we can gradually migrate to junit4 if we want to without having to do a massive migration. I really haven't looked very carefully at the base LuceneTestCase class, but I can successfully comingle Junit3 and Junit4 testcases so I thought it was worth discussing. Note that I didn't do *anything* except get the tests to run. That is, other than adding things like @Before and @After and @Test, I didn't take advantage of any of the Junit4 features. If there's enough interest, I'll clean some things up, make a JIRA (I don't see anything in there already on this topic) and submit a patch in the next week. And this is *really* something I'd like someone else's eyes on.... Best Erick
