refactor: pull out _read_json_from_file()

facilitates test mocking

pipeline/feature_extractors.py

@@ -356,6 +356,14 @@ class JSONFeatureExtractor(FeatureExtractor):
     def _source_from_dict(self, d):
         return Source(d["source"], d["path"], d["provider"])
 
+    def _read_json_from_file(self, file):
+        """Read a JSON file and return the contents
+
+        Method exists to allow for mocking in tests
+        """
+        with open(file, "r") as f:
+            return json.load(f)
+
     def run(self):
 
         # only pipeline JSON format for now