This reverts commit 8cb3cdff, reversing
changes made to 3bc747bd.

Reason: This test already exists in `SharedGeneratorTests`.
Ref:
https://github.com/rails/rails/blob/master/railties/test/generators/shared_generator_tests.rb#L109..L112
https://github.com/rails/rails/blob/master/railties/test/generators/app_generator_test.rb#L55..L56