Merge pull request #195 from rspec/myron/ruby-2-5

Add Ruby 2.5 to travis build.

Author: myronmarston

travis/.travis.yml

@@ -5,6 +5,7 @@ cache:
   directories:
     - ../bundle
 before_install:
+  - gem update --system # https://github.com/travis-ci/travis-ci/issues/8978#issuecomment-354036443
   - unset _JAVA_OPTIONS
   - "script/clone_all_rspec_repos"
   # Note this doesn't work on JRUBY 2.0.0 mode so we don't do it, the excluded versions are broken on Ruby 2.3
@@ -21,6 +22,7 @@ rvm:
   - 2.2.9
   - 2.3.6
   - 2.4.3
+  - 2.5.0
   - ruby-head
   - ree
   - rbx-3

travis/script/functions.sh

@@ -80,11 +80,7 @@ function run_spec_suite_for {
       pushd ../$1
       unset BUNDLE_GEMFILE
       bundle_install_flags=`cat .travis.yml | grep bundler_args | tr -d '"' | grep -o " .*"`
-      if is_mri_192_plus; then
-        travis_retry eval "RUBYOPT=$RUBYOPT:'--enable rubygems' bundle install $bundle_install_flags"
-      else
-        travis_retry eval "bundle install $bundle_install_flags"
-      fi
+      travis_retry eval "(unset RUBYOPT; exec bundle install $bundle_install_flags)"
       run_specs_and_record_done
       popd
     else