Five 1.5.6 testbrowser and recent version of mechanize

Doing development with Plone 3.1, I encountered a KeyError when I tried to use Five.testbrowser.Browser:

Browser()
KeyError: '_seek'

I eventually found that my system (currently Ubuntu 8.04) had the package "python-mechanize" 0.1.7b, which masks the one provided by Zope 2.10 (0.1.2b). Unfortunatly there has been API changes between 0.1.2b and 0.1.7b... (see classes UserAgent/UserAgentBase)

The solution is to tell buildout to get mechanize egg 0.1.2b: this way it will mask the system library.

[buildout]
versions = versions
eggs=
   ...
   mechanize

[versions]
mechanize = 0.1.2b

Et voila!