Cannot generate a generator spec when generating a generator

[tragiclifestories]

(Sorry for the crazy Dr Seuss issue name - and sorry if this has been reported before, it's very difficult to search for ... )

What Ruby, Rails and RSpec versions are you using?

Ruby version: 2.5.3p105
Rails version: 5.2.2
Rspec version: 3.8

• rspec-core 3.8.0
• rspec-expectations 3.8.2
• rspec-mocks 3.8.0
• rspec-rails 3.8.2
• rspec-support 3.8.0

Observed behaviour

With RSpec as the project-wide default test framework, rails generate generator always errors out.

$ bin/rails g generator foobar
Running via Spring preloader in process 45230
      create  lib/generators/foobar
      create  lib/generators/foobar/foobar_generator.rb
      create  lib/generators/foobar/USAGE
      create  lib/generators/foobar/templates
       error  rspec [not found]

I think this is because there is not a generator spec generator, so the rails generator generator is looking for something that isn't there.

Expected behaviour

A spec/lib/generators/foobar_generator_spec.rb file is generated with the helpers from spec/support/generators (run_generator and friends) available (I guess that would need to be required in spec_helper by default as well).

Can you provide an example app?

https://github.com/tragiclifestories/rspec-generator-issue

[tragiclifestories]

Digging around I discovered that this project is using ammeter which has solved my immediate problem. However, it would still be nice if RSpec would generate a spec file on rails g generator foo ... I leave it to you folks to decide whether it's worth the time to implement.

[JonRowe]

This would be a great easy PR for someone, you can either use one of our existing templates to produce this or you can make it skip.

[ConSou]

I can work on this issue.

[JonRowe]

Generator spec generators are now available on master.