added keyword to jspg

tests/fixtures/puncs.json

@@ -1067,7 +1067,7 @@
         "schemas": [
           {
             "$id": "polymorphic_org_punc.request",
-            "$ref": "organization.family"
+            "$family": "organization"
           }
         ]
       },
@@ -1080,6 +1080,21 @@
             "$ref": "organization"
           }
         ]
+      },
+      {
+        "name": "invalid_family_punc",
+        "public": false,
+        "schemas": [
+          {
+            "$id": "invalid_family_punc.request",
+            "$family": "organization",
+            "properties": {
+              "extra": {
+                "type": "string"
+              }
+            }
+          }
+        ]
       }
     ],
     "tests": [
@@ -1240,6 +1255,23 @@
             "path": "/first_name"
           }
         ]
+      },
+      {
+        "description": "invalid schema due to family exclusivity violation",
+        "schema_id": "invalid_family_punc.request",
+        "data": {
+          "id": "org-2",
+          "type": "organization",
+          "name": "Strict Corp",
+          "extra": "value"
+        },
+        "valid": false,
+        "expect_errors": [
+          {
+            "code": "INVALID_SCHEMA",
+            "path": ""
+          }
+        ]
       }
     ]
   },