Correct behaviors for open_file:

 * charset should be a downcased string.
 * content_encoding reflects Content-Encoding, as an array of downcased strings.
 * Non-UTF input is transformed to UTF-8, so that `external_encoding` is now "utf-8" with `charset` the original character set.

Author: gkellogg

lib/rdf/spec/http_adapter.rb

@@ -64,19 +64,28 @@
       WebMock.stub_request(:get, uri).to_return(body: "foo", headers: {"Content-Type" => "text/turtle"})
       RDF::Util::File.open_file(uri) do |f|
         expect(f.content_type).to eq "text/turtle"
-        expect(f.charset).to eq Encoding::UTF_8
-        expect(f.content_encoding).to eq "utf-8"
+        expect(f.charset).to eq "utf-8"
         expect(f.external_encoding.to_s.downcase).to eq "utf-8"
         opened.opened
       end
     end
 
-    it "sets content_type and encoding if provided" do
-      WebMock.stub_request(:get, uri).to_return(body: "foo", headers: {"Content-Type" => "text/turtle ; charset=ISO-8859-4"})
+    it "sets content_type and encoding if provided and UTF" do
+      WebMock.stub_request(:get, uri).to_return(body: "foo".force_encoding("UTF-16"), headers: {"Content-Type" => "text/turtle ; charset=UTF-16"})
       RDF::Util::File.open_file(uri) do |f|
         expect(f.content_type).to eq "text/turtle"
-        expect(f.charset).to eq "ISO-8859-4"
-        expect(f.external_encoding.to_s.downcase).to eq "iso-8859-4"
+        expect(f.charset).to eq "utf-16"
+        expect(f.external_encoding.to_s.downcase).to eq "utf-16"
+        opened.opened
+      end
+    end
+
+    it "sets content_type and encoding to UTF-8 if provided and not UTF" do
+      WebMock.stub_request(:get, uri).to_return(body: "foo".force_encoding("ISO-8859-4"), headers: {"Content-Type" => "text/turtle ; charset=ISO-8859-4"})
+      RDF::Util::File.open_file(uri) do |f|
+        expect(f.content_type).to eq "text/turtle"
+        expect(f.charset).to eq "iso-8859-4"
+        expect(f.external_encoding.to_s.downcase).to eq "utf-8"
         opened.opened
       end
     end