Fix block support in example.duplicate_with

Update spec to verify block exists in cloned example

Author: bootstraponline

lib/rspec/core/example.rb

@@ -138,8 +138,10 @@ def duplicate_with(metadata_overrides={})
 
         # don't clone the example group because the new example
         # must belong to the same example group (not a clone).
+        #
+        # block is nil in new_metadata so we have to get it from metadata.
         Example.new(example_group, description.clone,
-                    new_metadata, new_metadata[:block])
+                    new_metadata, metadata[:block])
       end
 
       # @private

spec/rspec/core/example_spec.rb

@@ -84,13 +84,17 @@ def metadata_hash(*args)
 
   describe '#duplicate_with' do
     it 'successfully duplicates an example' do
-      example = example_group.example { raise 'first' }
+      error_string = 'first'
+      example = example_group.example { raise error_string }
       example2 = example.duplicate_with({ :custom_key => :custom_value })
 
       # ensure metadata is unique for each example
       expect(example.metadata.object_id).to_not eq(example2.metadata.object_id)
       expect(example.metadata[:custom_key]).to eq(nil)
+      expect(&example.metadata[:block]).to raise_error(error_string)
+
       expect(example2.metadata[:custom_key]).to eq(:custom_value)
+      expect(&example2.metadata[:block]).to raise_error(error_string)
 
       # cloned examples must have unique ids
       expect(example.id).to_not eq(example2.id)