have_db_column of_type can't compare types with activerecord-jdbc-adapter/rails 5

[wintersolutions]

When I run the following spec in MRI everything works:

it { is_expected.to have_db_column(:example).of_type(:string) }

When I run it on JRuby 9.1.2 and with activerecord-jdbc-adapter (github: 'jruby/activerecord-jdbc-adapter', branch: 'rails-5') I get:

Expected Keyword to have db column named language_code of type string of limit 2 (FooBar has a db column named example of type #ActiveModel::Type::String:0x4c082a7d, not string.)

This seems to be the case for all types of attributes, not only strings. A possible workaround, i.e. comparing to ActiveModel::Type::String on JRuby, is not possible since were getting a instance instead of class when we call to_s i.e. ActiveModel::Type::String:0x4c082a7d.

That means shoulda-matchers will not be compatible with rails 5 on JRuby.

Relevant line:
https://github.com/thoughtbot/shoulda-matchers/blob/v3.1.1/lib/shoulda/matchers/active_record/have_db_column_matcher.rb#L152

[wintersolutions]

Found similar issues with have_db_column(:example).with_options(limit: 42) and enum_for matchers. I wrote the following monkeypatch to get my specs running again:

if RUBY_PLATFORM == 'java'
  class Shoulda::Matchers::ActiveRecord::HaveDbColumnMatcher

    protected

    def correct_column_type?
      return true unless @options.key?(:column_type)

      if matched_column.type.class.to_s =~ /#{@options[:column_type].to_s}/i
        true
      else
        @missing = "#{model_class} has a db column named #{@column} " <<
            "of type #{matched_column.type.class.to_s} which did not match #{@options[:column_type]}."
        false
      end
    end

    def correct_limit?
      return true unless @options.key?(:limit)

      if matched_column.type.limit.to_s == @options[:limit].to_s
        true
      else
        @missing = "#{model_class} has a db column named #{@column} " <<
            "of limit #{matched_column.type.limit}, " <<
            "not #{@options[:limit]}."
        false
      end
    end
  end

  class Shoulda::Matchers::ActiveRecord::DefineEnumForMatcher

    protected

    def column_type_is_integer?
      column.type.class.to_s =~ /Integer/
    end
  end
end

[mcmire]

@wintersolutions Unfortunately, we don't officially support JRuby and haven't in quite some time. I'm not sure when this will be addressed, but I will keep this here in the meantime. Sorry I can't give you more :(