perl-Test-Unit-0.25-32.fc31 fails build with perl 5.30 because a test started to fail:

$ perl -Ilib t/assert.t                                    
STARTING TEST RUN                                                                         
1..40                                                                                     
[...]
ok PASS test_assert_raises

not ok ERROR test_numericness
t/tlib/AssertTest.pm:48 - test_numericness(Class::Inner::__A26)
For string '0xF00', expect f but got t
ok PASS test_fail_assert_null

That's caused by a change in perl. Perl 5.28 handles it as string:

$ perl -e 'print qq{YES\n} if q{0xF00} == 0'
YES

While perl 5.30 handles it as a number:

$ perl -e 'print qq{YES\n} if q{0xF00} == 0'

The failing test has a relevant notice at t/tlib/AssertTest.pm:37:

    '0xF00' => 'f', # controversial?  but if you +=10 then it's == 10