Chefspec 3.2.0 introduced berkshelf integration lately.  However this will decrease the test speed as chefspec will setup and teardown berkshelf all the time. 

Below is a snipped to similar chefspec#242 .  But in addition, I removed the vendoring of the cookbook in development.   Here is my rake task to do that build:

task :build do
  File.open("chefignore", "a").write("*aspnet_skeleton*")
  berksfile.install path: "vendor/cookbooks"
  FileUtils.rmdir "vendor/cookbooks/aspnet_skeleton"
end

This approach has several advantages: [1] chefspec doesn’t need to build the vendored directory everytime rspec is invoked, [2] you can run the test against the source code directory for a fast TDD feedback cycle, and [3]  build and test phases for your CI pipeline can be separated.

Here’s how chefspec consumes the vendored cookbook_path and cookbook-in-development simultaenously:

RSpec.configure do |config|
  config.cookbook_path = %w(vendor/cookbooks ../)
end