Bug#962727: libwww-mechanize-perl: build fails on IPv6-only buildds

[Adrian Bunk]

Source: libwww-mechanize-perl
Version: 2.00-1
Severity: serious
Tags: ftbfs

https://buildd.debian.org/status/fetch.php?pkg=libwww-mechanize-perl&arch=all&ver=2.00-1&stamp=1591965277&raw=0

...
# Test server http://127.0.0.1:39495 as PID 1878

#   Failed test 'First fetch works'
#   at t/cookies.t line 74.
#          got: '500'
#     expected: '200'

#   Failed test 'First cookie matches'
#   at t/cookies.t line 78.
#          got: undef
#     expected: 'Cookie #1'

#   Failed test 'Right title'
#   at t/cookies.t line 79.
#          got: undef
#     expected: 'Home of Cookie #1'

#   Failed test 'Second fetch works'
#   at t/cookies.t line 84.
#          got: '500'
#     expected: '200'

#   Failed test 'Second cookie matches'
#   at t/cookies.t line 88.
#          got: undef
#     expected: 'Cookie #2'

#   Failed test 'Right title'
#   at t/cookies.t line 89.
#          got: undef
#     expected: 'Home of Cookie #2'

#   Failed test 'Cookie did not change...'
#   at t/cookies.t line 97.
#          got: undef
#     expected: 'Cookie #2'

#   Failed test '... but back to the first page title'
#   at t/cookies.t line 98.
#          got: undef
#     expected: 'Home of Cookie #1'

#   Failed test 'Cookie did not change...'
#   at t/cookies.t line 106.
#          got: undef
#     expected: 'Cookie #2'

#   Failed test 'On the proper 3rd page'
#   at t/cookies.t line 107.
#          got: undef
#     expected: 'No cookies sent'

#   Failed test 'Got the third cookie'
#   at t/cookies.t line 115.
#          got: undef
#     expected: 'Cookie #3'

#   Failed test 'Title is correct'
#   at t/cookies.t line 116.
#          got: undef
#     expected: 'Home of Cookie #3'
# Looks like you failed 12 tests of 14.
t/cookies.t ..............................
1..14
TestServer: You can connect to your server at http://localhost:39495/
ok 1 - An object of class 'WWW::Mechanize' isa 'WWW::Mechanize'
not ok 2 - First fetch works
not ok 3 - First cookie matches
not ok 4 - Right title
not ok 5 - Second fetch works
not ok 6 - Second cookie matches
not ok 7 - Right title
not ok 8 - Cookie did not change...
not ok 9 - ... but back to the first page title
not ok 10 - Cookie did not change...
not ok 11 - On the proper 3rd page
not ok 12 - Got the third cookie
not ok 13 - Title is correct
ok 14 - Signaled the child process
Dubious, test returned 12 (wstat 3072, 0xc00)
Failed 12/14 subtests
...
Test Summary Report
-------------------
t/cookies.t                            (Wstat: 3072 Tests: 14 Failed: 12)
  Failed tests:  2-13
  Non-zero exit status: 12
Files=61, Tests=798, 83 wallclock secs ( 0.29 usr  0.10 sys + 15.79 cusr  2.28 csys = 18.46 CPU)
Result: FAIL
Failed 1/61 test programs. 12/798 subtests failed.
make[2]: *** [Makefile:948: test_dynamic] Error 255


See #962019 for discussion of a similar problem in a different package.