現象
$ pear install phpunit/PHPUnit_SkeletonGenerator
すると以下のエラーがでてハマった。
attempting to discover channel "phpunit"...
Attempting fallback to https instead of http on channel "phpunit"...
unknown channel "phpunit" in "phpunit/PHPUnit_SkeletonGenerator"
invalid package name/package file "phpunit/PHPUnit_SkeletonGenerator"
install failed
解決策
チャネルが登録できていなかったらしい。
$ sudo pear channel-discover pear.phpunit.de
$ sudo pear install phpunit/PHPUnit_SkeletonGenerator