Never re-raise NameError and always default to CollectionDecorator (#795)

* minor fix to error raising on collection decoration.

* Don't re-raise NameError in collection_decorator_class.

* Add more tests.

lib/draper/decorator.rb

@@ -223,8 +223,7 @@ module Draper
     def self.collection_decorator_class
       name = collection_decorator_name
       name.constantize
-    rescue NameError => error
-      raise if name && !error.missing_name?(name)
+    rescue NameError
       Draper::CollectionDecorator
     end
 

spec/draper/decorator_spec.rb

@@ -145,13 +145,6 @@ module Draper
           ProductDecorator.decorate_collection([], options)
         end
       end
-
-      context "when a NameError is thrown" do
-        it "re-raises that error" do
-          allow_any_instance_of(String).to receive(:constantize) { Draper::DecoratedEnumerableProxy }
-          expect{ProductDecorator.decorate_collection([])}.to raise_error NameError, /Draper::DecoratedEnumerableProxy/
-        end
-      end
     end
 
     describe ".decorates" do
@@ -230,6 +223,21 @@ module Draper
       end
     end
 
+    describe '.collection_decorator_class' do
+      it 'defaults to CollectionDecorator' do
+        allow_any_instance_of(String).to receive(:constantize) { SomethingThatDoesntExist }
+        expect(ProductDecorator.collection_decorator_class).to be Draper::CollectionDecorator
+      end
+
+      it 'infers collection decorator based on name' do
+        expect(ProductDecorator.collection_decorator_class).to be ProductsDecorator
+      end
+
+      it 'infers collection decorator base on name for namespeced model' do
+        expect(Namespaced::ProductDecorator.collection_decorator_class).to be Namespaced::ProductsDecorator
+      end
+    end
+
     describe ".decorates_association" do
       protect_class Decorator
 

spec/spec_helper.rb

@@ -24,7 +24,7 @@ class OtherDecorator < Draper::Decorator; end
 module Namespaced
   class Product < Model; end
   class ProductDecorator < Draper::Decorator; end
-
+  ProductsDecorator = Class.new(Draper::CollectionDecorator)
   class OtherDecorator < Draper::Decorator; end
 end