test yielding block of default_main_content

spec/unit/views/pages/show_spec.rb

@@ -5,16 +5,29 @@
   describe "the resource" do
     let(:helpers) { double resource: resource }
     let(:arbre_context) { Arbre::Context.new({}, helpers) }
+    subject(:page) { ActiveAdmin::Views::Pages::Show.new(arbre_context) }
 
     context 'when the resource does not respond to #decorator' do
       let(:resource) { 'Test Resource' }
 
       it "normally returns the resource" do
-        page = ActiveAdmin::Views::Pages::Show.new(arbre_context)
         expect(page.resource).to eq 'Test Resource'
       end
     end
 
+    context 'when you pass a block to main content' do
+      let(:block) { lambda { } }
+      let(:resource_class) { double(columns: [double('column', name: 'field')]) }
+      let(:resource) { double('resource', class: resource_class) }
+
+      before { allow(page).to receive(:active_admin_config).and_return(double(comments?: false))}
+
+      it 'appends it to the output' do
+        expect(page).to receive(:attributes_table).with(:field).and_yield
+        page.default_main_content(&block)
+      end
+    end
+
   end
 
 end