Learnings

Request spec failure (`render_template` matcher missing)

Context: My request spec failed: Failure/Error: expect(response).to render_template(:new) ... assert_template has been extracted to a gem. To continue using it, add gem 'rails-controller-testing' to your Gemfile. The render_template matcher in RSpec request specs relies on functionality (assert_template) that is no longer part of Rails core.
Resolution: I added gem 'rails-controller-testing' to the :test group in the Gemfile and ran bundle install.
Learning: I learned to be aware that testing helpers previously included in Rails core might be extracted into separate gems in newer versions. Error messages usually indicate the required gem (rails-controller-testing for render_template, assigns, assert_template).