The tests for yesod-core and http-conduit have started to fail lately on Debian, when the packages are built on IPv6-only hosts.
See here and here for the build logs, as well as here and here for the corresponding bug reports.

I believe that the tests are failing because streaming-common is using the AI_ADDRCONFIG flag on the getPossibleAddrs and or the bindPortGenEx functions. Could you please consider removing this flag? See also a discussion on http-client package which had the same problem and removed the above flag.