It appears that Kent Beck has been working in stealth mode on JUnit 4, and if
it wasn’t for a small slip in an interview a couple of months ago, nobody would
know.  It turns out that there already is some new code checked into their
CVS depot and Alexandru and I took a quick look there.

Here is what we found so far:

  • Annotations.  As we observed with
    , annotations let you do away with inheritance of a base class and
    make more sense than trying to cram test information into method names.
  • The @Test annotation has an expected attribute
    (probably similar to @ExpectedExceptions, but it’s hard to tell at
    this point)=.  I also note they only allow one class to be expected
    while TestNG lets you specify more than one).
  • There is a new @Ignore annotations, which we decided to specify
    as an attribute of @Test in TestNG (e.g. @Test(enabled = false)).
  • TestNG’s timeout and invocationCount also seem to be
    planned for JUnit.
  • Finer grained configuration access.  JUnit only allowed to
    around test methods, you can now do this at the suite
    level (TestNG offers even greater flexibility: around classes and around
  • Suites are being deprecated and they are looking for a way to describe
    collections of tests (quite a surprising decision, but may I suggest a file
    called…  I don’t know, junit.xml?).
  • There will be a converter (I invite the JUnit team to start off with
    and tweak the imports it generates
  • Run failures first (TestNG generates a testng-failures.xml for
  • Quoted from the todo file:  "be able to specify the order of
    tests (ewwww….)
    ".  Now that is very interesting…  They are
    just falling short of specifying test dependencies but as much as I find
    this feature crucial for non-unit testing, I question its use for unit
  • Groups!  Yes, that’s right.  A lot of people criticized the
    need for groups when they were introduced in TestNG a year ago, but we have
    definitely seen users like this feature and use it a lot.  It’s good to
    see JUnit follow the same path.

For more information, Alexandru posted a
more detailed
of the various features offered by JUnit 4 with his own comments.

A few comments now…

  • This is a pretty good start, and I am not surprised to see that
    dependent test methods are not planned for JUnit (this feature probably
    doesn’t belong to a unit-testing framework anyway).
  • I didn’t notice any new tests, so they are not using Test-Driven
    Development…  makes you wonder, uh?
  • There is still no separation of static and dynamic models.

    Having test groups is not very useful you can’t specify which groups to
    execute at runtime.  I hope JUnit will provide a less awkward way to
    invoke tests than putting them in a suite() method.  As you
    probably know by now if you are a regular reader of this blog, I still
    firmly believe that I shouldn’t have to recompile Java code if I want to run
    a different set of tests, which is the reason behind the existence of the
    testng.xml file in TestNG.

All in all, this is very exciting but I feel disappointed that no email was
sent to the JUnit mailing-list nor request for feedback posted on any blog: 
the JUnit team seems to have decided to work behind closed doors on this.

The JUnit mailing-list itself has 5800 subscribers (!) and would probably be
an invaluable way for them to get feedback.  I’m not quite sure what is the
driving vision behind JUnit 4 (besides TestNG :-)), but I certainly hope they
will be coming out of stealth mode and discuss it publicly soon.

At any rate, I am quite happy to see that things are finally moving in the
testing area!