Reload class with include-CodePudding

In the following situation, where include_class is a preference, can I somehow dynamically change the value of include_class and reload Image such that it instead includes the new value of include_class?

module Foo
  included do
    @test_var = :foo
  end
end

module Bar
  included do
    @test_var = :bar
  end
end

Config.include_class = Foo

class Image
  include Config.include_class
end

# ... run tests with default configuration for Image, where Image.test_var = :foo

Config.include_class = OtherClass

# ... how can I reload or re-evaluate Image such that Image.test_var = :bar?

Context

I am trying to test whether a configuration option (that is normally set by an initializer) has the correct effects on the application. Because this is part of a test suite the the modules and classes might be loaded before and all configuration changes need to be reset after the test.

CodePudding user response：

I'd suggest to use refinements instead, in this case class will be reset after the test (on any other stuff). I implemented an example without active_concern, but the idea should be clear. This example can be executed with plain ruby as a single script.

# This part is just to keep close to your example
class Config
  def self.include_class=(klass)
    @@include_class = klass
  end

  def self.include_class
    @@include_class ||= nil
  end
end

# Assuming Bar is a default module and Foo will be used in tests
module Bar
  def print_something
    puts 'I am Bar'
  end
end

module Foo
  def print_something
    puts 'I am Foo'
  end
end

# Setting default module
Config.include_class = Bar

# Defining Image class
class Image
  include Config.include_class
end

#Changing config
Config.include_class = Foo

# This is a refinement
module ImagePatch
  # It will include current Config.include_class
  # Note that methods from Bar that are not present in Foo will not be removed
  refine Image do
    include Config.include_class
  end
end

# Here we will create module where refinement is activated
module TestEnv
  # Activating the patch
  using ImagePatch
  Image.new.print_something #=>I am Foo
end

#Outside of the TestEnv module we enjoy the default Image class
Image.new.print_something #=>I am Bar