Error running tests

[panta]

I'm not familiar with ruby, so I apologize in advance if I am doing something terribly stupid.

I'm trying to run the tests, but it always give me the same error:

$ gem install bundler
$ bundle install --with=development
$ bundle exec rake test
/usr/local/bin/ruby -w -I"lib:lib:test" -I"/gems/gems/rake-12.3.0/lib" "/gems/gems/rake-12.3.0/lib/rake/rake_test_loader.rb" "test/fixtures/schema.rb" "test/plugin/test_in_sql.rb" "test/plugin/test_out_sql.rb"
/gems/gems/activesupport-4.2.10/lib/active_support/core_ext/enumerable.rb:20: warning: method redefined; discarding old sum

File does not exist:

rake aborted!
Command failed with status (1): [ruby -w -I"lib:lib:test" -I"/gems/gems/rake-12.3.0/lib" "/gems/gems/rake-12.3.0/lib/rake/rake_test_loader.rb" "test/fixtures/schema.rb" "test/plugin/test_in_sql.rb" "test/plugin/test_out_sql.rb" ]
/gems/gems/rake-12.3.0/exe/rake:27:in `<top (required)>'
/usr/local/bin/bundle:23:in `load'
/usr/local/bin/bundle:23:in `<main>'
Tasks: TOP => test
(See full trace by running task with --trace)

This happens both on my machine (OSX) and in a debian Docker container I've put together to exclude local problems (in the docker container I've installed libpq-dev and postgres, and created the database user and db).

[repeatedly]

I and travis-ci setup doesn't happen this problem so your ruby setup is something wrong. Sorry I don't know what is the wrong.

[panta]

Probably I'm doing something wrong, because it happens on both my OSX machine and on the dockerized debian. I'm using ruby 2.4.1 btw.

Is the following the correct procedure?

$ gem install bundler
$ bundle install --with=development
$ bundle exec rake test