I just attempted to run the test suite in PHP 5.4.9. Eight of the 13 test scripts failed or outright died.
all_test.php : fatal error
dom_testcase.php : 15 assertion failures
element_testcase.php : 5 failures
invalid_testcase.php : fatal error (the cause of all_test.php's death)
mass_test.php : appears to lock up
misc_testcase.php : 2 failures
std_testcase.php : 6 failures
strip_testcase.php : 2 failures
We have never really "supported" the tests. They were given to us by someone else.
Please feel free to submit updated versions of them.
Closing because PHP 5.4 is outdated by now.