Add scopedRef to metaschema. Tweak test.

Author: Peter Amstutz

schema_salad/metaschema/metaschema.yml

@@ -139,6 +139,16 @@ $graph:
         the item is transformed to a JSON object with the key assigned to the
         field specified by `mapSubject` and the value assigned to the field
         specified by `mapPredicate`.
+    - name: scopedRef
+      type: ["null", boolean]
+      doc: |
+        If the field contains a relative reference, it must be resolved by
+        searching for valid document references in each successive parent
+        scope.  For example, a reference of "foo" in the context "#foo/bar/baz"
+        will first check for the existence of "#foo/bar/baz/foo", followed
+        by "#foo/bar/foo", then "#foo/foo" and then finally "#foo".  The first
+        valid URI in the search order shall be used as the fully resolved value
+        of the identifier.
 
 - name: SpecializeDef
   type: record

tests/test_examples.py

@@ -119,20 +119,34 @@ def test_scoped_ref(self):
             "id": "foo",
             "blurb": {
                 "id": "bar",
+                "blurg": {
+                    "id": "quux",
+                    "blurb": {
+                        "id": "q2"
+                    }
+                },
                 "blurb": {
                     "id": "baz",
-                    "ref": ["foo", "bar", "baz"]
+                    "ref": ["foo", "bar", "baz", "quux", "quux/q2"]
                 }
             }
         }, "http://example2.com/")
 
         self.assertEquals({'id': 'http://example2.com/#foo',
                            'blurb': {
                                'id': 'http://example2.com/#foo/bar',
+                               "blurg": {
+                                   "id": "http://example2.com/#foo/bar/quux",
+                                   "blurb": {
+                                       "id": "http://example2.com/#foo/bar/quux/q2"
+                                   }
+                               },
                                'blurb': {
                                    'ref': ['http://example2.com/#foo',
                                            'http://example2.com/#foo/bar',
-                                           'http://example2.com/#foo/bar/baz'],
+                                           'http://example2.com/#foo/bar/baz',
+                                           'http://example2.com/#foo/bar/quux',
+                                           'http://example2.com/#foo/bar/quux/q2'],
                                    'id': 'http://example2.com/#foo/bar/baz'}}},
                           ra)