Can't lookup a vocabulary from a BNode.

Author: gkellogg

lib/rdf/vocabulary.rb

@@ -304,9 +304,11 @@ def expand_pname(pname)
       # @param [RDF::URI] uri
       # @return [Vocabulary]
       def find(uri)
+        uri = RDF::URI(uri) if uri.is_a?(String)
+        return nil unless uri.uri? && uri.valid?
         RDF::Vocabulary.detect do |v|
           if uri.length >= v.to_uri.length
-            RDF::URI(uri).start_with?(v.to_uri)
+            uri.start_with?(v.to_uri)
           else
             v.to_uri.to_s.sub(%r([/#]$), '') == uri.to_s
           end

spec/vocabulary_spec.rb

@@ -324,6 +324,16 @@
         expect(RDF::Vocabulary.find(term.to_s)).to equal vocab
       end
     end
+    it "returns nil if argument is a BNode" do
+      terms.each do |term, vocab|
+        expect(RDF::Vocabulary.find(RDF::Node.new("a"))).to be_nil
+      end
+    end
+    it "returns nil if argument an invalid URI" do
+      terms.each do |term, vocab|
+        expect(RDF::Vocabulary.find("a b c")).to be_nil
+      end
+    end
   end
 
   describe ".find_term" do