PHPUnit

phpunit 3.5.14 includes a testing framework (for creating dummy DB records and for faking a FE), Selenium support, a now-working VFS and many bug fixes.

Thanks to Waidelich, Carsten Koenig, Patrick Shriner, Christopher Lörken and Christian Kuhn who have contributed code and bug fixes.

From the changelog:

2010-04-27 Oliver Klee <typo3-coding@oliverklee.de>
    * Release version 3.4.12.
    * Fixed Bug #7230: Update PHPUnit to the latest version
    * Fixed Bug #7234: Update some things in the manual

2010-04-15 Oliver Klee <typo3-coding@oliverklee.de>
    * Fixed Bug #5544: Invalid IDs for the checkboxes

2010-04-14 Oliver Klee <typo3-coding@oliverklee.de>
    * Fixed Bug #7228: Typo in the CSS file

2010-04-13 Oliver Klee <typo3-coding@oliverklee.de>
    * Fixed Bug #5560: "All extensions" cannot be selected

2010-04-12 Oliver Klee <typo3-coding@oliverklee.de>
    * Fixed Task #6922: Rename the test cases from *_testcase to *Test

2010-03-19 Oliver Klee <typo3-coding@oliverklee.de>
    * Fixed Bug #5550: Convert all locallang files to XML
    * Add Feature #5553: Make the PHP comments warning a flash message

2010-03-18 Oliver Klee <typo3-coding@oliverklee.de>
    * Fixed Bug #5902: Link for running single test doesn't work from within running a testcase

2010-03-03 Oliver Klee <typo3-coding@oliverklee.de>
    * Fixed Bug #6638: Support for *Test.php names instead of _testcase.php, patch by Sebastian Kurfürst
    * Fixed Bug #6672: Files included twice, patch by Ingo Renner
    * Fixed Bug #6561: Remove the .project file from SVN

2010-02-18 Oliver Klee <typo3-coding@oliverklee.de>
    * Fixed Bug #5542: Add CDATA for all script tags
    * Fixed Bug #5569: Add and clean up the class documentation comments
    * Fixed Bug #6452: Update PHPUnit version 3.4.7 to 3.4.11
    * Fixed Bug #5511: Show a warning if PHP comments are stripped

2010-01-25 Oliver Klee <typo3-coding@oliverklee.de>
    * Fixed Bug #5836: Don't use makeInstanceClassName in TYPO3 4.3

2010-01-19 Oliver Klee <typo3-coding@oliverklee.de>
    * Fixed Bug #5557: Drop the display of the changelog
    * Fixed bug #5900: Update PHPUnit to 3.4.7
    * Fixed Bug #5555: Register all classes for the autoloader
    * Fixed Bug #5950: Remove the mentioning of the ECT from the extension description

2010-01-18 Oliver Klee <typo3-coding@oliverklee.de>
    * Fixed Bug #5510: Make sure all phpunit tests actually run

2010-01-06 Oliver Klee <typo3-coding@oliverklee.de>
    * Fixed bug #5568: Change all tests to use the @test annotation

The phpunit extension for Typo3 version 4.x has gained several contributors over the last year. Since Kasper Ligaard is busy, Oliver Klee has stepped up as new release manager for the phpunit extension. He, along with Kasper Ligaard and Michael Klapper are now all co-leaders of the extension.

The upgrading to PHPUnit 3.3.0 (from 3.2.21) is not expected to cause any issues. If you do run into trouble, then remember that you can point phpunit at a PHPUnit 3.x of you own choosing. Do this from the Extension Manager. Thus, if you run in to any issues with PHPUnit 3.3.0, then you can switch back and forth between PHPUnit versions, while you sort out your problems.

The phpunit extension will switch to including PHPUnit version 3.3, as soon as it is final. If you want to use another version of PHPUnit, then remember that this can be setup in the extension manager.
You can verify which version of PHPUnit you are running at the top of thep phpunit back-end interface.