Added rspec tests for the new behaviour of merge accepting empty strings
Added rspec tests for the new behaviour of merge accepting empty strings

added test that '' is accepted
changed a test that a number is correctly rejected with a type error

HelenCampbell/puppetlabs-stdlib,yadavnikhil/puppetlabs-stdlib,puppetlabs/puppetlabs-stdlib,fuel-infra/puppetlabs-stdlib,jbondpdx/puppetlabs-stdlib,DavidS/puppetlabs-stdlib