3.6RC4 has a bug in line 288 of TextUI/Command.php. --coverage-html option isn’t parsed correctly. Even I fixes the misspelling it causes another error, and also the latest source code on Github looks very different from RC4, so I just gave up to use RC4.
Upgrade to 3.6RC4 from 3.5 took some time and downgrade as well.
% pear uninstall phpunit/PHPUnit % pear config-set preferred_state beta % pear install phpunit/PHPUnit % pear upgrade --alldeps -f
% pear uninstall ... # Not sure if this was the easiest way, I just uninstall all dependencies individually % pear config-set preferred_state stable % pear install --alldeps phpunit/PHPUnit
% phpunit --coverage-html ./report BankAccountTest % cd report % python -m SimpleHTTPServer 9090