In case a clue might be gleaned right away from `make test`, I'm posting the final part of the output here:

[394/401/1] test_xmlrpc
../Python-2.7.13/Lib/threading.py:846: DeprecationWarning: sys.exc_clear() not supported in 3.x; use except clauses
  self.__exc_clear()
[395/401/1] test_xpickle
[396/401/1] test_xrange
[397/401/1] test_zipfile
[398/401/1] test_zipfile64
test_zipfile64 skipped -- test requires loads of disk-space bytes and a long time to run
[399/401/1] test_zipimport
[400/401/1] test_zipimport_support
[401/401/1] test_zlib
359 tests OK.
1 test failed:
    test_gdb
1 test altered the execution environment:
    test_import
40 tests skipped:
    test_aepack test_al test_applesingle test_bsddb test_bsddb185
    test_bsddb3 test_cd test_cl test_codecmaps_cn test_codecmaps_hk
    test_codecmaps_jp test_codecmaps_kr test_codecmaps_tw test_curses
    test_dl test_gl test_idle test_imgfile test_kqueue
    test_linuxaudiodev test_macos test_macostools test_msilib
    test_ossaudiodev test_scriptpackages test_smtpnet
    test_socketserver test_startfile test_sunaudiodev test_tcl
    test_timeout test_tk test_ttk_guionly test_ttk_textonly
    test_turtle test_urllib2net test_urllibnet test_winreg
    test_winsound test_zipfile64
8 skips unexpected on linux2:
    test_bsddb test_bsddb3 test_idle test_tcl test_tk test_ttk_guionly
    test_ttk_textonly test_turtle
make: *** [test] Error 1