don't modify the parameter string in Entity.entity_class

lib/diaspora_federation/entity.rb

@@ -119,11 +119,11 @@ module DiasporaFederation
     #
     # @see .entity_name
     #
-    # @param [String] class_name "snake_case" class name
+    # @param [String] entity_name "snake_case" class name
     # @return [Class] entity class
-    def self.entity_class(class_name)
-      raise InvalidEntityName, "'#{class_name}' is invalid" unless class_name =~ /^[a-z]*(_[a-z]*)*$/
-      class_name.sub!(/^[a-z]/, &:upcase)
+    def self.entity_class(entity_name)
+      raise InvalidEntityName, "'#{entity_name}' is invalid" unless entity_name =~ /^[a-z]*(_[a-z]*)*$/
+      class_name = entity_name.sub(/^[a-z]/, &:upcase)
       class_name.gsub!(/_([a-z])/) { Regexp.last_match[1].upcase }
 
       raise UnknownEntity, "'#{class_name}' not found" unless Entities.const_defined?(class_name)

spec/lib/diaspora_federation/entity_spec.rb

@@ -211,6 +211,12 @@ XML
         expect(Entity.entity_class("test_entity")).to eq(Entities::TestEntity)
       end
 
+      it "should not change the input string" do
+        entity_name = "test_entity"
+        Entity.entity_class(entity_name)
+        expect(entity_name).to eq("test_entity")
+      end
+
       it "raises an error when the entity name contains special characters" do
         expect {
           Entity.entity_class("te.st-enti/ty")