Chef 13 is out, to test your code for deprecations, you can put Test Kitchen in a mode where any deprecations cause the chef run to fail.
Ensure your .kitchen.yml includes:
provisioner: deprecations_as_errors: true
and then run Test Kitchen as usual. Test Kitchen will fail if any deprecation errors are issued.
This feature was added in Test Kitchen 1.13, which shipped in ChefDK 1.0.