If a blank value is passed in for collection, the code inside of install_utils.rb will evaluate implementation.to_sym to null and return an error

[michael-riddle]

We need to surround the code at

beaker_puppet_helpers/lib/beaker_puppet_helpers/install_utils.rb

Line 55 in 75307d3

repos = REPOS[implementation.to_sym][:release]

with a check to ensure the key being evaluated actually exists in the REPOS hash and raise an error if it does not.