STSPG-2386: Dynamic hermes weights

Author: duane

lib/hermes/deliverer.rb

@@ -82,7 +82,7 @@ def aggregate_weight_for_type(type, filter: [])
       }
 
       # then sum up all of the weights across our providers
-      providers.map(&:weight).inject(0, :+)
+      providers.count == 1 ? 1 : providers.map(&:weight).inject(0, :+)
     end
 
     def weighted_provider_for_type(type, filter: [])
@@ -99,7 +99,9 @@ def weighted_provider_for_type(type, filter: [])
         filter.empty? || filter.include?(provider_instance.class)
       }
 
-      # if we end up with an empty list we're in troubl
+      return providers.first if providers.count == 1
+
+      # if we end up with an empty list we're in trouble
       raise ProviderNotFoundError, "Empty provider list found for type:#{type} filter:#{filter}" unless providers.any?
 
       # get the aggregate weight, and make sure it's more than 0 after the filter