Don't resolve @base if it is an absolute IRI.

Author: gkellogg

lib/json/ld/context.rb

@@ -196,7 +196,9 @@ def empty?
     def base=(value)
       if value
         raise JsonLdError::InvalidBaseIRI, "@base must be a string: #{value.inspect}" unless value.is_a?(String) || value.is_a?(RDF::URI)
-        @base = @base ? @base.join(value) : RDF::URI(value).dup
+        value = RDF::URI(value).dup
+        value = @base.join(value) if @base && value.relative?
+        @base = value
         @base.canonicalize! if @options[:canonicalize]
         raise JsonLdError::InvalidBaseIRI, "@base must be an absolute IRI: #{value.inspect}" unless @base.absolute? || !@options[:validate]
         @base

spec/api_spec.rb

@@ -95,7 +95,7 @@
             end if File.exist?(framed) && File.exist?(frame)
 
             it "toRdf" do
-              expect(RDF::Repository.load(filename, adapter: adapter, debug: @debug)).to be_equivalent_graph(RDF::Repository.load(ttl), trace: @debug)
+              expect(RDF::Repository.load(filename, format: :jsonld, adapter: adapter, debug: @debug)).to be_equivalent_graph(RDF::Repository.load(ttl), trace: @debug)
             end if File.exist?(ttl)
           end
         end

spec/suite_helper.rb

@@ -179,7 +179,7 @@ def run(rspec_example = nil)
       def to_quad(thing)
         case thing
         when RDF::URI
-          thing.canonicalize.to_ntriples
+          thing.to_ntriples
         when RDF::Node
           escaped(thing)
         when RDF::Literal::Double