acceptance_tests is faied on Ruby 2.4

[cucumber]

acceptance_tests is faied on Ruby 2.4

[mattwynne]

@junaruga thanks so much for digging into this. It looks like the diff-lcs issue is fixed in their 1.3 release. Could you try upgrading and see if you can send us a PR?

[junaruga]

@mattwynne I succeeded the both tests after diff-lcs was upgraded to 1.3.
We do not need to change our code to use diff-lcs 1.3.

$ ruby -v
ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-linux]

$ git pull

$ bundle install --path vendor/bundle

$ bundle list
Gems included by the bundle:
  * aruba (0.14.2)
  * backports (3.6.8)
  * builder (3.2.3)
  * bundler (1.14.3)
  * childprocess (0.5.9)
  * contracts (0.14.0)
  * cucumber (3.0.0.pre.1)
  * cucumber-core (2.0.0)
  * cucumber-wire (0.0.1)
  * diff-lcs (1.3)
  * ffi (1.9.17)
  * gherkin (4.0.0)
  * multi_json (1.12.1)
  * multi_test (0.1.2)
  * rake (12.0.0)
  * rspec (3.5.0)
  * rspec-core (3.5.4)
  * rspec-expectations (3.5.0)
  * rspec-mocks (3.5.0)
  * rspec-support (3.5.0)
  * thor (0.19.4)

$ bundle exec rake unit_tests
...
20 examples, 0 failures

$ bundle exec rake acceptance_tests
...
21 scenarios (21 passed)
120 steps (120 passed)
0m9.730s