testing README instructions no longer work

[sneakyimp]

The README file in the tests folder outlines a process which no longer works. In particular, the first command doesn't work:

pear channel-discover pear.phpunit.de

It fails, the error complaint mentioning an invalid channel file:

$ pear channel-discover pear.phpunit.de
Error: No version number found in <channel> tag
Discovering channel pear.phpunit.de over http:// failed with message: channel-add: invalid channel.xml file
Trying to discover channel pear.phpunit.de over https:// instead
Error: No version number found in <channel> tag
Discovery of channel "pear.phpunit.de" failed (channel-add: invalid channel.xml file)

There's a stackoverflow post addressing this problem which says you can't install phpunit using pear anymore. PHPUnit documentation suggests installing either via composer or by downloading a PHAR file.