Rake db:migrateを実行できない

Question

ubuntsでruby on railsを動かしたく、ドットインストールのRuby On Rails入門に沿って
①rails new app
②Gemfileの gem 'therubyracer',platform: :rubyをコメントアウトから外す

③appフォルダ内でrails sでサーバーの立ち上げ

④rails generate scaffold User name:string score:integer
まで実行し、いずれもエラーなく動きました。
しかし、次にrake db:migrateを実行しようとしたら、
rake aborted!
Don't know how to build task 'test:recent' (see --tasks)
というエラーが発生し、rake db:createなど多くのrakeコマンド(?)を実行しても必ず上記と同じエラーが発生してしまいました。
エラーを検索して、'test;recent'が出ている質問があまりないことや、rakeやbundleをアップデートするなどの方法を試しました。が、いずれもうまくいかなかったので質問させていただきました。よろしくお願いいたします。

---rake vesion---
rake, version 11.2.0

---ruby version---
ruby 2.3.1p112 (2016-04-26 revision 54768) [i386-linux-gnu]

---rails version---
Rails 4.0.2

---rake db;migrateを実行したときのエラー---
rake aborted!
Don't know how to build task 'test:recent' (see --tasks)
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/test_unit/testing.rake:98:in block in <top (required)>' /var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/test_unit/testing.rake:65:in <top (required)>'
/var/lib/gems/2.3.0/gems/activesupport-4.0.2/lib/active_support/dependencies.rb:223:in load' /var/lib/gems/2.3.0/gems/activesupport-4.0.2/lib/active_support/dependencies.rb:223:in block in load'
/var/lib/gems/2.3.0/gems/activesupport-4.0.2/lib/active_support/dependencies.rb:214:in load_dependency' /var/lib/gems/2.3.0/gems/activesupport-4.0.2/lib/active_support/dependencies.rb:223:in load'
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/test_unit/railtie.rb:15:in block in <class:TestUnitRailtie>' /var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/railtie.rb:201:in instance_exec'
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/railtie.rb:201:in block in run_tasks_blocks' /var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/railtie.rb:201:in each'
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/railtie.rb:201:in run_tasks_blocks' /var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/application.rb:243:in block in run_tasks_blocks'
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/engine/railties.rb:17:in each' /var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/engine/railties.rb:17:in each'
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/application.rb:243:in run_tasks_blocks' /var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/engine.rb:446:in load_tasks'
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/railtie/configurable.rb:30:in method_missing' /home/zico/app2/Rakefile:6:in <top (required)>'
/var/lib/gems/2.3.0/gems/rake-11.2.0/exe/rake:27:in `<top (required)>'
(See full trace by running task with --trace)

Answer 1

どうやら、rake test:recentはtest/unitに依存したタスクのようで、しかもtest/unitはRuby 2.2以降ではGemとして入れないといけないようです。

Gemfileにgem 'test-unit'を書き足してみてください。

Comments

[itsuki]

回答ありがとうございます。Gemfileにgem 'test-unit'を追加した後にrake db:migrateコマンドを実行しました。すると、
Could not find gem 'test-unit (>= 0) ruby' in the gems available on this machine.
Run `bundle install` to install missing gems.
が表示され、bundle installを行い、再びrake db:migrateコマンドを実行すると、
rake aborted!
Don't know how to build task 'test:recent' (see --tasks)
が出ました。

---rake db:migrate---

rake aborted!
Don't know how to build task 'test:recent' (see --tasks)
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/test_unit/testing.rake:98:in `block in <top (required)>'
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/test_unit/testing.rake:65:in `<top (required)>'
/var/lib/gems/2.3.0/gems/activesupport-4.0.2/lib/active_support/dependencies.rb:223:in `load'
/var/lib/gems/2.3.0/gems/activesupport-4.0.2/lib/active_support/dependencies.rb:223:in `block in load'
/var/lib/gems/2.3.0/gems/activesupport-4.0.2/lib/active_support/dependencies.rb:214:in `load_dependency'
/var/lib/gems/2.3.0/gems/activesupport-4.0.2/lib/active_support/dependencies.rb:223:in `load'
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/test_unit/railtie.rb:15:in `block in <class:TestUnitRailtie>'
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/railtie.rb:201:in `instance_exec'
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/railtie.rb:201:in `block in run_tasks_blocks'
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/railtie.rb:201:in `each'
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/railtie.rb:201:in `run_tasks_blocks'
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/application.rb:243:in `block in run_tasks_blocks'
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/engine/railties.rb:17:in `each'
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/engine/railties.rb:17:in `each'
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/application.rb:243:in `run_tasks_blocks'
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/engine.rb:446:in `load_tasks'
/var/lib/gems/2.3.0/gems/railties-4.0.2/lib/rails/railtie/configurable.rb:30:in `method_missing'
/home/zico/app2/Rakefile:6:in `<top (required)>'
/var/lib/gems/2.3.0/gems/rake-11.2.0/exe/rake:27:in `<top (required)>'
(See full trace by running task with --trace)

[itsuki]

・sudo gem update rake
・bundle update rake
・rake db:migtate
で実行できました!(何が原因か分かりませんでしたけど・・・)
ありがとうございました!