Question

I have just added Cucumber to my Rails app via the following steps:

Adding

group :test do
  gem 'cucumber'
end

to my Gemfile.

Running bundle install

Followed by rails generate cucumber:install

When there are no features, Cucumber seems to run as expected.

But when I add a feature file and run bundle exec cucumber I get the following

uninitialized constant Gherkin::Parser::Parser (NameError)
/Users/purinkle/.rvm/gems/ruby-1.9.3-p286@radfords/gems/cucumber-1.2.1/lib/cucumber/feature_file.rb:34:in parse'
/Users/purinkle/.rvm/gems/ruby-1.9.3-p286@radfords/gems/cucumber-1.2.1/lib/cucumber/runtime/features_loader.rb:28:inblock in load’
/Users/purinkle/.rvm/gems/ruby-1.9.3-p286@radfords/gems/cucumber-1.2.1/lib/cucumber/runtime/features_loader.rb:26:in each'
/Users/purinkle/.rvm/gems/ruby-1.9.3-p286@radfords/gems/cucumber-1.2.1/lib/cucumber/runtime/features_loader.rb:26:inload’
/Users/purinkle/.rvm/gems/ruby-1.9.3-p286@radfords/gems/cucumber-1.2.1/lib/cucumber/runtime/features_loader.rb:14:in features'
/Users/purinkle/.rvm/gems/ruby-1.9.3-p286@radfords/gems/cucumber-1.2.1/lib/cucumber/runtime.rb:170:infeatures’
/Users/purinkle/.rvm/gems/ruby-1.9.3-p286@radfords/gems/cucumber-1.2.1/lib/cucumber/runtime.rb:46:in run!'
/Users/purinkle/.rvm/gems/ruby-1.9.3-p286@radfords/gems/cucumber-1.2.1/lib/cucumber/cli/main.rb:43:inexecute!’
/Users/purinkle/.rvm/gems/ruby-1.9.3-p286@radfords/gems/cucumber-1.2.1/lib/cucumber/cli/main.rb:20:in execute'
/Users/purinkle/.rvm/gems/ruby-1.9.3-p286@radfords/gems/cucumber-1.2.1/bin/cucumber:14:in‘
/Users/purinkle/.rvm/gems/ruby-1.9.3-p286@radfords/bin/cucumber:23:in load'
/Users/purinkle/.rvm/gems/ruby-1.9.3-p286@radfords/bin/cucumber:23:in‘

Answer 1

You probably have some other gem that implements Gherkin.

If you have spinach installed, for example, that will create a conflict: when cucumber requires Gherkin, it will pull from the spinach gem instead of from gherkin

Cucumber‘s Gherkin::Parser is a module with a Parser class in it [1].

Spinach uses gherkin-ruby [2], which implements the whole thing in a different way, but using the same names [3] (poor implementation IMO).

Try uninstalling spinach (removing it from your Gemfile and a bundle update should be enough) or whatever you have that might be causing a name clash.

• [1] https://github.com/cucumber/gherkin/blob/master/lib/gherkin/parser/parser.rb#L14
• [2] https://github.com/codegram/gherkin-ruby
• [3] https://github.com/codegram/gherkin-ruby/blob/master/lib/gherkin/parser/parser.rb#L13