Merge pull request #39 from ruby-rdf/feature/delete_enum

Test `RDF::Enumerable` handling in `Mutable#delete`

lib/rdf/spec/mutable.rb

@@ -106,6 +106,13 @@
  end
  end
 
+ it 'handles Enumerables' do
+ if subject.mutable?
+ subject.delete(@statements)
+ expect(subject.find { |s| subject.has_statement?(s) }).to be_nil
+ end
+ end
+
  it "is_expected.to support wildcard deletions" do
  if subject.mutable?
  # nothing deleted