Change method of reporting target data

src/python/pants/goal/run_tracker.py

@@ -429,14 +429,16 @@ def _create_dict_with_nested_keys_and_val(cls, keys, value):
     :param primitive value: The value of the information being stored.
     :return: dict of nested keys leading to the value.
     """
-    current_index = len(keys) - 1
 
     if len(keys) > 1:
-      new_val = {keys[current_index]: value}
-      new_keys = keys[:current_index]
+      new_keys = keys[:-1]
+      new_val = {keys[-1]: value}
       return cls._create_dict_with_nested_keys_and_val(new_keys, new_val)
     elif len(keys) == 1:
-      return {keys[current_index]: value}
+      return {keys[0]: value}
+    else:
+      raise ValueError('Keys must contain at least one key.')
+
 
   @classmethod
   def _merge_list_of_keys_into_dict(cls, data, keys, value, index=0):

src/python/pants/task/testrunner_task_mixin.py

@@ -71,7 +71,7 @@ def report_all_info_for_single_test(self, scope, target, test_name, test_info):
 
     Given the dict of test information
     {'time': 0.124, 'result_code': 'success', 'classname': 'some.test.class'}
-    iterate through each item and report the single item with report_test_info.
+    iterate through each item and report the single item with _report_test_info.
 
     :param string scope: The scope for which we are reporting the information.
     :param Target target: The target that we want to store the test information under.
@@ -80,9 +80,9 @@ def report_all_info_for_single_test(self, scope, target, test_name, test_info):
     """
     for test_info_key, test_info_val in test_info.items():
       key_list = [test_name, test_info_key]
-      self.report_test_info(scope, target, key_list, test_info_val)
+      self._report_test_info(scope, target, key_list, test_info_val)
 
-  def report_test_info(self, scope, target, keys, test_info):
+  def _report_test_info(self, scope, target, keys, test_info):
     """Add test information to target information.
 
     :param string scope: The scope for which we are reporting information.

tests/python/pants_test/goal/test_run_tracker.py

@@ -61,10 +61,8 @@ def test_write_stats_to_json_file(self):
   def test_create_dict_with_nested_keys_and_val(self):
     keys = []
 
-    self.assertEquals(
-      RunTracker._create_dict_with_nested_keys_and_val(keys, 'something'),
-      None
-    )
+    with self.assertRaises(ValueError):
+      RunTracker._create_dict_with_nested_keys_and_val(keys, 'something')
 
     keys += ['one']
     self.assertEquals(