Rails 4.2 concern content ignored in test environment - ruby-on-rails

Question

I'm stuck in a really weird issue. I recently updated from rails 4.1 to 4.2. In 4.1 everything worked fine. But now, in 4.2, it seems model concern content is beig ignored, even if the concern is found.
Putting it simple. I have a Client model which belongs to an Address, relationship that is defined in an Addressable concern:
app/models/client.rb
class Client < ActiveRecord::Base
include Addressable
end
app/models/address.rb
class Address < ActiveRecord::Base
end
app/models/concerns/addressable.rb
module Addressable
extend ActiveSupport::Concern
included do
belongs_to :address
end
No problem in development environment. I can do Client.new.address without problems. But in test environment that same line gives me an unknow method address error. If I move belongs_to :address to Client then it works again. The module is being included, because there is no error about this, and if I change the name to Adressabledewdewded then, of course, there is an error.
Same happens with validation methods, etc.
I have been debugging this but I don't find the root. I have copied my development.rb as test.rb and restarted the server but still. I can't reproduce this in a freshly new Rails 4.2 application, so it has to have something to do with my application or the updating process, but no idea where.
Anyone has a clue?
Thanks
UPDATE
This is the stack trace on doing Client.new.address in the console in test environment (in development it works):
NoMethodError: undefined method `address' for #<Client:0xbc89dac0>
from /home/marc/.gem/ruby/2.1.3/gems/activemodel-4.2.0/lib/active_model/attribute_methods.rb:433:in `method_missing'
from (irb):3
from /home/marc/.gem/ruby/2.1.3/gems/railties-4.2.0/lib/rails/commands/console.rb:110:in `start'
from /home/marc/.gem/ruby/2.1.3/gems/railties-4.2.0/lib/rails/commands/console.rb:9:in `start'
from /home/marc/.gem/ruby/2.1.3/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:68:in `console'
from /home/marc/.gem/ruby/2.1.3/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
from /home/marc/.gem/ruby/2.1.3/gems/railties-4.2.0/lib/rails/commands.rb:17:in `<top (required)>'
from /home/marc/.gem/ruby/2.1.3/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:274:in `require'
from /home/marc/.gem/ruby/2.1.3/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:274:in `block in require'
from /home/marc/.gem/ruby/2.1.3/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:240:in `load_dependency'
from /home/marc/.gem/ruby/2.1.3/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:274:in `require'
from /home/marc/projects/clients_webs/a_project/bin/rails:8:in `<top (required)>'
from /home/marc/.gem/ruby/2.1.3/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:268:in `load'
from /home/marc/.gem/ruby/2.1.3/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:268:in `block in load'
from /home/marc/.gem/ruby/2.1.3/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:240:in `load_dependency'
from /home/marc/.gem/ruby/2.1.3/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:268:in `load'
from /home/marc/.gem/ruby/2.1.3/gems/spring-1.3.1/lib/spring/commands/rails.rb:6:in `call'
from /home/marc/.gem/ruby/2.1.3/gems/spring-1.3.1/lib/spring/command_wrapper.rb:38:in `call'
from /home/marc/.gem/ruby/2.1.3/gems/spring-1.3.1/lib/spring/application.rb:183:in `block in serve'
from /home/marc/.gem/ruby/2.1.3/gems/spring-1.3.1/lib/spring/application.rb:156:in `fork'
from /home/marc/.gem/ruby/2.1.3/gems/spring-1.3.1/lib/spring/application.rb:156:in `serve'
from /home/marc/.gem/ruby/2.1.3/gems/spring-1.3.1/lib/spring/application.rb:131:in `block in run'
from /home/marc/.gem/ruby/2.1.3/gems/spring-1.3.1/lib/spring/application.rb:125:in `loop'
from /home/marc/.gem/ruby/2.1.3/gems/spring-1.3.1/lib/spring/application.rb:125:in `run'
from /home/marc/.gem/ruby/2.1.3/gems/spring-1.3.1/lib/spring/application/boot.rb:18:in `<top (required)>'
from /home/marc/.rubies/ruby-2.1.3/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /home/marc/.rubies/ruby-2.1.3/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
UPDATE
Result of Client.ancestors in both environments is (without the only difference of instance identity, of course):
=> [Client (call 'Client.connection' to establish a connection), Trader, Addressable, Kaminari::ConfigurationMethods, Kaminari::ActiveRecordModelExtension, Client::GeneratedAssociationMethods, #<#<Class:0xba3b1c70>:0xba3b1d24>, ActiveRecord::Base, Kaminari::ActiveRecordExtension, GlobalID::Identification, ActiveRecord::Store, ActiveRecord::Serialization, ActiveModel::Serializers::Xml, ActiveModel::Serializers::JSON, ActiveModel::Serialization, ActiveRecord::Reflection, ActiveRecord::NoTouching, ActiveRecord::Transactions, ActiveRecord::Aggregations, ActiveRecord::NestedAttributes, ActiveRecord::AutosaveAssociation, ActiveModel::SecurePassword, ActiveRecord::Associations, ActiveRecord::Timestamp, ActiveModel::Validations::Callbacks, ActiveRecord::Callbacks, ActiveRecord::AttributeMethods::Serialization, ActiveRecord::AttributeMethods::Dirty, ActiveModel::Dirty, ActiveRecord::AttributeMethods::TimeZoneConversion, ActiveRecord::AttributeMethods::PrimaryKey, ActiveRecord::AttributeMethods::Query, ActiveRecord::AttributeMethods::BeforeTypeCast, ActiveRecord::AttributeMethods::Write, ActiveRecord::AttributeMethods::Read, ActiveRecord::Base::GeneratedAssociationMethods, #<#<Class:0xb8df1c14>:0xb8df1c50>, ActiveRecord::AttributeMethods, ActiveModel::AttributeMethods, ActiveRecord::Locking::Pessimistic, ActiveRecord::Locking::Optimistic, ActiveRecord::AttributeDecorators, ActiveRecord::Attributes, ActiveRecord::CounterCache, ActiveRecord::Validations, ActiveModel::Validations::HelperMethods, ActiveSupport::Callbacks, ActiveModel::Validations, ActiveRecord::Integration, ActiveModel::Conversion, ActiveRecord::AttributeAssignment, ActiveModel::ForbiddenAttributesProtection, ActiveRecord::Sanitization, ActiveRecord::Scoping::Named, ActiveRecord::Scoping::Default, ActiveRecord::Scoping, ActiveRecord::Inheritance, ActiveRecord::ModelSchema, ActiveRecord::ReadonlyAttributes, ActiveRecord::Persistence, ActiveRecord::Core, Object, PP::ObjectMixin, ActiveSupport::Dependencies::Loadable, JSON::Ext::Generator::GeneratorMethods::Object, Kernel, BasicObject]
And doing Client.reflections.keys makes address to appear in development but not in test.

Answer 1

I got it. The thing is that a gem that is present only in my test environment (json-schema), has addressable gem as a dependency, which is defining an Addressable module. When Rails tries to autoload Addressable it finds the class defined by addressable instead of my concern class. The module is being included but it is not the one I thought.
When updating my Gemfile, json-schema has been updated and now depends on addresable, since November 2014.
Hard one to catch :)