[DRE-maint] Bug#888174: ruby-whitequark-parser: FTBFS on ruby2.5: Update test_current for 2.5.0

[Chris West (Faux)]

Source: ruby-whitequark-parser
Version: 2.3.3.1-1
Severity: important
User: debian-ruby at lists.debian.org
Usertags: ruby2.5

Dear Maintainer,

This package fails to build against ruby2.5. Soon, there will
be a transition to ruby2.5, and this package will FTBFS in sid.

There may be some details on the wiki about common problems:
https://wiki.debian.org/Teams/Ruby/Ruby25Transition

Build log excerpt:

Finished in 4.243802s, 201.7059 runs/s, 17410.8037 assertions/s.

  1) Failure:
TestCurrent#test_current [/build/ruby-whitequark-parser-2.3.3.1/test/test_current.rb:22]:
Update test_current for 2.5.0

856 runs, 73888 assertions, 1 failures, 0 errors, 0 skips
rake aborted!
Command failed with status (1): [ruby -w -I"test"  "/usr/lib/ruby/vendor_ruby/rake/rake_test_loader.rb" "test/bug_163/test_runner_rewrite.rb" "test/test_base.rb" "test/test_current.rb" "test/test_diagnostic.rb" "test/test_diagnostic_engine.rb" "test/test_encoding.rb" "test/test_lexer.rb" "test/test_lexer_stack_state.rb" "test/test_parse_helper.rb" "test/test_parser.rb" "test/test_source_buffer.rb" "test/test_source_comment.rb" "test/test_source_comment_associator.rb" "test/test_source_map.rb" "test/test_source_range.rb" "test/test_source_rewriter.rb" "test/test_source_rewriter_action.rb" "test/test_static_environment.rb" -v]

Tasks: TOP => default
(See full trace by running task with --trace)
ERROR: Test "ruby2.5" failed. Exiting.
dh_auto_install: dh_ruby --install /build/ruby-whitequark-parser-2.3.3.1/debian/ruby-whitequark-parser returned exit code 1
debian/rules:6: recipe for target 'binary' failed
make: *** [binary] Error 1
dpkg-buildpackage: error: debian/rules binary subprocess returned exit status 2

Full build log:
https://rbuild.fau.xxx/2018-01-23/ruby-whitequark-parser.log

Please fix it!

Cheers,
Chris.