fix 'undefined method for nil:NilClass' on wrong xmls

Author: Alexander Zagaynov

lib/nori.rb

@@ -46,6 +46,8 @@ def parse(xml)
 
     parser = load_parser @options[:parser]
     parser.parse(cleaned_xml, @options)
+  rescue NoMethodError => e
+    raise ArgumentError, "Parsing error, might be malformed xml"
   end
 
   private

spec/nori/nori_spec.rb

@@ -640,6 +640,11 @@
         expect(parse(' ')).to eq({})
       end
 
+
+      it "handle incorrect xml string" do
+        incorrect_xml = "<?xml version=\"1.0\" encoding=\"utf-8\">\n<request>\n <opcode>0</opcode>\n</request>\n"
+        expect { parse(incorrect_xml) }.to raise_error(ArgumentError, /Parsing error/)
+      end
     end
   end