attempting to cast a string that isn't a valid real number leads to the exception:

Error while parsing smartvar
 | NoMethodError: undefined method `cast_value_integer' for #<Foreman::Parameters::Caster:0x000000107a4da0>
 | /home/tbrisker/foreman/app/services/foreman/parameters/caster.rb:84:in `cast_real'
 | /home/tbrisker/foreman/app/services/foreman/parameters/caster.rb:33:in `casted_value'
 | /home/tbrisker/foreman/app/services/foreman/parameters/caster.rb:17:in `cast!'
 | /home/tbrisker/foreman/app/models/lookup_value.rb:71:in `validate_and_cast_value'
... snipped rest of stacktrace