Add tests to make sure that value objects and expanded term definitions have only a single value for @type, unless framing in the case of value objects.

Fixes #484.

Author: gkellogg

lib/json/ld/expand.rb

@@ -146,13 +146,16 @@ def expand(input, active_property, context,
             # Otherwise, if the value of result's @value member is not a string and result contains the key @language, an invalid language-tagged value error has been detected (only strings can be language-tagged) and processing is aborted.
             raise JsonLdError::InvalidLanguageTaggedValue,
                   "when @language is used, @value must be a string: #{output_object.inspect}"
-          elsif framing && !Array(output_object['@type']).all? {|t|
-                  t.is_a?(String) && RDF::URI(t).valid? && !t.start_with?('_:') ||
-                  t.is_a?(Hash) && t.empty?}
+          elsif output_object['@type'] &&
+            (!Array(output_object['@type']).all? {|t|
+                t.is_a?(String) && RDF::URI(t).valid? && !t.start_with?('_:') ||
+                t.is_a?(Hash) && t.empty?} ||
+             !framing && !output_object['@type'].is_a?(String))
             # Otherwise, if the result has a @type member and its value is not an IRI, an invalid typed value error has been detected and processing is aborted.
             raise JsonLdError::InvalidTypedValue,
                   "value of @type must be an IRI or '@json': #{output_object.inspect}"
-          elsif !framing && !output_object.fetch('@type', '').is_a?(String)
+          elsif !framing && !output_object.fetch('@type', '').is_a?(String) &&
+                  RDF::URI(t).valid? && !t.start_with?('_:')
             # Otherwise, if the result has a @type member and its value is not an IRI, an invalid typed value error has been detected and processing is aborted.
             raise JsonLdError::InvalidTypedValue,
                   "value of @type must be an IRI or '@json': #{output_object.inspect}"