Comment 7 for bug 1176147

There is no possibility of keeping packages "locally" as this concept does not really exist in our setting. Travis-CI (and other hosted CI services) provide a fresh and clean VM with each build. This is a superior in terms of finding bugs in a project's packaging and installation process, and corresponds to an effective way of deploying a cloud service, so artifacts of prior installs cannot interfere with an updated version. This is also superior in terms of finding bugs in a project's packaging, and

However, because of lxml and a variety of other such large libraries, the rather monolithic project I am working on has resorted to pre-building a virtualenv compatible with Travis, which we then clone to travis for each build. We lose the testing of our packaging, but gain a more fluid workflow by skipping the install time. A good tradeoff today, but one that I can hope will not be permanent.