desc "Merges the assemblies"
task :merge do
  mkdir DEPLOY_DIR unless File.exists?(DEPLOY_DIR)
  cp "xunit.dll".expand_to(:build_dir), "xunit.dll".expand_to(:deploy_dir)
  cp "Rhino.Mocks.dll".expand_to(:build_dir), "Rhino.Mocks.dll".expand_to(:deploy_dir)
  assemblies_to_merge = ["xUnit.BDDExtensions.dll", "StructureMap.dll", "StructureMap.AutoMocking.dll"]
  ilmerge "xunit.bddextensions.dll", assemblies_to_merge
end

Ruby is a fantastic language. The more I learn about it the more I actually like it. Let’s have a look at how this task is implemented. First of all I opened up Ruby’s string class and added new methods to it (this is called MonkeyPatching, and worth a blog post on its own )

class String
  def escape
    "\"#{self.to_s}\""
  end

  def expand_to dir_symbol
    case dir_symbol
      when :build_dir
        path = BUILD_DIR
      when :source_dir
        path = SOURCE_DIR
      when :externals_dir
        path = EXTERNALS_DIR
      when :deploy_dir
        path = DEPLOY_DIR
    end    

    File.join(path, self.to_s)
  end
end

And here is the actual ilmerge – method. It simply gets the complete path to the ILMerge.exe (not shown here), expands the name to all assemblies that have to be merged and escapes them, before the actual call to ILMerge is issued over the console …

def ilmerge(output_name, assemblies)
  ilmerge = get_tool :ILMerge
  expanded_assemblies = assemblies.map do |x|
    x.expand_to(:build_dir).escape
  end

  sh "#{ilmerge.escape} /out:#{output_name.expand_to(:deploy_dir).escape} #{expanded_assemblies.join(" ")}"
end

Currently 3 assemblies pop out of the Rake build. These are xunit.dll, xunit.bddextensions.dll and Rhino.Mocks.dll. While it’s technically no problem to merge them into a single assembly (and of course I would love to have it that way) there are two problems currently not solved. The R# runner dynamically loads the xunit.dll to run the tests and StructureMap.AutoMocking.dll dynamically loads Rhino.Mocks.dll. That’s the reason why I’m currently not able to merge it.

Any suggestions how to solve that?