lib/har/archive.rb in har-0.0.3 vs lib/har/archive.rb in har-0.0.4

@@ -11,10 +11,10 @@
     end
 
     def self.by_merging(hars)
       hars = hars.dup
 
-      result = hars.shift
+      result = hars.shift or raise ArgumentError, "no HARs given"
       result = from_file(result) unless result.kind_of? self
 
       hars.each do |har|
         result.merge! har.kind_of?(self) ? har : from_file(har)
       end