$ ruby -v
ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x86_64-linux]

$ bundle install --path vendor/bundle

$ bundle exec rake -T
bundler: failed to load command: rake (/usr/local/ruby-2.7.1/bin/rake)
Gem::Exception: can't find executable rake for gem rake. rake is not currently included in the bundle, perhaps you meant to add it to your Gemfile?
  /usr/local/ruby-2.7.1/lib/ruby/2.7.0/bundler/rubygems_integration.rb:374:in `block in replace_bin_path'
  /usr/local/ruby-2.7.1/lib/ruby/2.7.0/bundler/rubygems_integration.rb:402:in `block in replace_bin_path'
  /usr/local/ruby-2.7.1/bin/rake:23:in `<top (required)>'

$ git diff
diff --git a/.travis.yml b/.travis.yml
index 0d92a15..9d2c642 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,4 +9,4 @@ rvm:
   - "2.6"
   - "2.7"
   - "ruby-head"
-script: rake
+script: bundle exec rake
diff --git a/abrt.gemspec b/abrt.gemspec
index 7b40c32..f3d33fa 100644
--- a/abrt.gemspec
+++ b/abrt.gemspec
@@ -28,6 +28,7 @@ Gem::Specification.new do |s|
     s.cert_chain = ["voxik-public_cert.pem"]
   end
 
+  s.add_development_dependency(%q<rake>)
   s.add_development_dependency(%q<rspec>, ["~> 3.5"])
 end

  1) ABRT handles exception in 'abrt.rb' with RubyGems disabled
     Failure/Error:
       expect { system "ruby --disable-gems #{abrt_rb}" }
         .to output(/\A\Z/).to_stdout_from_any_process
         .and output(output_message_pattern).to_stderr_from_any_process
     
       expected block to output /\A\/builddir\/abrt-0.4.0\/spec\/..\/lib\/abrt.rb:\d+:in `<main>': can't modify frozen Array(: \[1, 2, 3\])? \((FrozenError|RuntimeError)\)\n\Z/ to stderr, but output "/usr/bin/ruby-mri: No such file or directory -- /builddir/abrt-0.4.0/spec/../lib/abrt.rb (LoadError)\n"
     # ./spec/abrt_spec.rb:9:in `block (3 levels) in <top (required)>'

  2) ABRT handles exception in 'abrt.rb' with RubyGems enabled
     Failure/Error:
       expect { system "ruby --disable-gems -rrubygems #{abrt_rb}" }
         .to output(/\A\Z/).to_stdout_from_any_process
         .and output(output_message_pattern).to_stderr_from_any_process
     
       expected block to output /\A\/builddir\/abrt-0.4.0\/spec\/..\/lib\/abrt.rb:\d+:in `<main>': can't modify frozen Array(: \[1, 2, 3\])? \((FrozenError|RuntimeError)\)\n\Z/ to stderr, but output "/usr/bin/ruby-mri: No such file or directory -- /builddir/abrt-0.4.0/spec/../lib/abrt.rb (LoadError)\n"
     # ./spec/abrt_spec.rb:15:in `block (3 levels) in <top (required)>'