Add .find_by! and .find_by methods to Resource

Author: Derek Lindahl

README.md

@@ -349,6 +349,15 @@ like so:
 > Order.find(1)
 # <Order id=1 total=54.47>
 
+> Order.find_by(id:1)
+# <Order id=1 total=54.47>
+
+> Order.find_by!(id:-1, state:'active')
+# Frenetic::ResourceNotFound: Couldn't find Order with id=-1, state=active
+
+> Order.find_by(id:-1)
+# nil
+
 > Order.all
 # [<Order id=1 total=54.47>,<Order id=2 total=42.00>]
 ```

lib/frenetic/concerns/member_rest_methods.rb

@@ -18,6 +18,16 @@ def find(params)
         new(response.body) if response.success?
       end
 
+      def find_by!(params)
+        find(params)
+      end
+
+      def find_by(params)
+        find_by!(params)
+      rescue ClientError
+        nil
+      end
+
       def all
         return [] if test_mode?
         response = api.get(collection_url)

spec/concerns/member_rest_methods_spec.rb

@@ -85,6 +85,25 @@
     end
   end
 
+  describe '.find_by' do
+    before { @stubs.api_description }
+
+    subject { MyTempResource.find_by(id:1) }
+
+    it 'delegates to .find' do
+      allow(MyTempResource).to receive(:find).and_return(nil)
+      subject
+      expect(MyTempResource).to have_received(:find)
+    end
+
+    context 'for an unknown resource' do
+      it 'returns nil' do
+        allow(MyTempResource).to receive(:find).and_raise(Frenetic::ClientError.new({}))
+        expect{subject}.to_not raise_error
+      end
+    end
+  end
+
   describe '.all' do
     before { @stubs.api_description }