【Ruby】invalid byte sequence in US-ASCII (ArgumentError) が出たとき【Rails】

RailsRubyでもですが)を使っていて例えば何かの画像を開こうとFile.openメソッドを使った時に

/usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/lib/rspec/core/notifications.rb:228:in `split': invalid byte sequence in US-ASCII (ArgumentError)
        from /usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/lib/rspec/core/notifications.rb:228:in `failure_lines'
        from /usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/lib/rspec/core/notifications.rb:164:in `colorized_message_lines'
        from /usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/lib/rspec/core/notifications.rb:191:in `fully_formatted'
        from /usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/lib/rspec/core/notifications.rb:95:in `block in fully_formatted_failed_examples'
        from /usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/lib/rspec/core/notifications.rb:94:in `each'
        from /usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/lib/rspec/core/notifications.rb:94:in `each_with_index'
        from /usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/lib/rspec/core/notifications.rb:94:in `fully_formatted_failed_examples'
        from /usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/lib/rspec/core/formatters/base_text_formatter.rb:34:in `dump_failures'
        from /usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/lib/rspec/core/reporter.rb:134:in `block in notify'
        from /usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/lib/rspec/core/reporter.rb:133:in `each'
        from /usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/lib/rspec/core/reporter.rb:133:in `notify'
        from /usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/lib/rspec/core/reporter.rb:114:in `finish'
        from /usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/lib/rspec/core/reporter.rb:55:in `report'
        from /usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/lib/rspec/core/runner.rb:107:in `run_specs'
        from /usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/lib/rspec/core/runner.rb:85:in `run'
        from /usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/lib/rspec/core/runner.rb:69:in `run'
        from /usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/lib/rspec/core/runner.rb:37:in `invoke'
        from /usr/local/rvm/gems/ruby-2.1.2/gems/rspec-core-3.1.4/exe/rspec:4:in `<top (required)>'
        from /usr/local/rvm/gems/ruby-2.1.2/bin/rspec:23:in `load'
        from /usr/local/rvm/gems/ruby-2.1.2/bin/rspec:23:in `<main>'
        from /usr/local/rvm/gems/ruby-2.1.2/bin/ruby_executable_hooks:15:in `eval'
        from /usr/local/rvm/gems/ruby-2.1.2/bin/ruby_executable_hooks:15:in `<main>'

のようなエラーが出た場合の解決法としてFile.openメソッドの第二引数に

"r:UTF-8"

"rb:UTF-8"

 

等を指定するというのは調べるとよく出てきますが、それでもうまくいかない場合は以下の2つも確認してみると良いかもしれません。

  1. そもそもパスが間違っている
  2. macのプレビューの「書き出し」などで拡張子を変換した(jpg -> png)などの画像を開こうとしている

この2つでもinvalid byte sequence in US-ASCII (ArgumentError) が出ます。

1.の場合にはもう少し違うエラーが出て欲しい...。