Cannot run rake test Rails

Question

I'm following Rails Tutorials by Michael Hartl (chapter 3). However, when I edit the Gemfile like he did and then run rake test, rails suggested me to put this line : config.web_console.development_only = false in the application config file. I did that and run bundle exec rake test again, here's the error message:

/home/ys/workspace/sample_app/db/schema.rb doesn't exist yet. Run `rake db:migrate` to create it, then try again. If you do not intend to use a database, you should instead alter /home/ys/workspace/sample_app/config/application.rb to limit the frameworks that will be loaded.
/home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `require': cannot load such file -- guard (LoadError)
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `block in require'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:240:in `load_dependency'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `require'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/guard-minitest-2.4.4/lib/minitest/guard_minitest_plugin.rb:4:in `<top (required)>'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `require'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `block in require'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:240:in `load_dependency'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `require'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/minitest-5.8.4/lib/minitest.rb:91:in `block in load_plugins'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/minitest-5.8.4/lib/minitest.rb:85:in `each'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/minitest-5.8.4/lib/minitest.rb:85:in `load_plugins'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/minitest-5.8.4/lib/minitest.rb:114:in `run'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/minitest-5.8.4/lib/minitest.rb:56:in `block in autorun'

I then proceeded to rake db:migrate, then run rake test again:

Running via Spring preloader in process 15638
/home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `require': cannot load such file -- guard (LoadError)
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `block in require'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:240:in `load_dependency'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `require'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/guard-minitest-2.4.4/lib/minitest/guard_minitest_plugin.rb:4:in `<top (required)>'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `require'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `block in require'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:240:in `load_dependency'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-4.2.6/lib/active_support/dependencies.rb:274:in `require'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/minitest-5.8.4/lib/minitest.rb:91:in `block in load_plugins'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/minitest-5.8.4/lib/minitest.rb:85:in `each'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/minitest-5.8.4/lib/minitest.rb:85:in `load_plugins'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/minitest-5.8.4/lib/minitest.rb:114:in `run'
    from /home/ys/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/minitest-5.8.4/lib/minitest.rb:56:in `block in autorun'

All I can guess is that there is something wrong with Ruby because I upgraded from 2.3.0 to 2.3.1 the other day as rails console complained about buggy, old version when I run bundle install. So, How to fix this?

Answer 1

https://github.com/guard/guard-minitest

Add the guard gem to your gem file.
gem 'guard'