From 53e1df5c3ee169144a2778c6d2ee13cc6af99429 Mon Sep 17 00:00:00 2001
From: Patrick McNeill <pmcneill@berklee.edu>
Date: Fri, 17 May 2013 17:57:57 -0400
Subject: [PATCH] Adds 'decorator_class?' method

Indicates whether a class can be decorated or not without resorting to a
rescue in application-level code.
---
 lib/draper/decoratable.rb       | 10 ++++++++++
 spec/draper/decoratable_spec.rb | 20 ++++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/lib/draper/decoratable.rb b/lib/draper/decoratable.rb
index 70ae4f90..2c39dd66 100644
--- a/lib/draper/decoratable.rb
+++ b/lib/draper/decoratable.rb
@@ -23,6 +23,10 @@ def decorator_class
       self.class.decorator_class
     end
 
+    def decorator_class?
+      self.class.decorator_class?
+    end
+
     # The list of decorators that have been applied to the object.
     #
     # @return [Array<Class>] `[]`
@@ -56,6 +60,12 @@ def decorate(options = {})
         decorator_class.decorate_collection(collection, options.reverse_merge(with: nil))
       end
 
+      def decorator_class?
+        decorator_class
+      rescue Draper::UninferrableDecoratorError
+        false
+      end
+
       # Infers the decorator class to be used by {Decoratable#decorate} (e.g.
       # `Product` maps to `ProductDecorator`).
       #
diff --git a/spec/draper/decoratable_spec.rb b/spec/draper/decoratable_spec.rb
index e880acbd..46ef1036 100644
--- a/spec/draper/decoratable_spec.rb
+++ b/spec/draper/decoratable_spec.rb
@@ -46,6 +46,26 @@ module Draper
       end
     end
 
+    describe "#decorator_class?" do
+      it "returns true for decoratable model" do
+        expect(Product.new.decorator_class?).to be_true
+      end
+
+      it "returns false for non-decoratable model" do
+        expect(Model.new.decorator_class?).to be_false
+      end
+    end
+
+    describe ".decorator_class?" do
+      it "returns true for decoratable model" do
+        expect(Product.decorator_class?).to be_true
+      end
+
+      it "returns false for non-decoratable model" do
+        expect(Model.decorator_class?).to be_false
+      end
+    end
+
     describe "#decorator_class" do
       it "delegates to .decorator_class" do
         product = Product.new