Make output placeholders like json.output index-able by name.

recipe_modules/raw_io/test_api.py

Index: recipe_modules/raw_io/test_api.py
diff --git a/recipe_modules/raw_io/test_api.py b/recipe_modules/raw_io/test_api.py
index d5affe4eaa7c47bfde7df9d4b9dac0d096f55f51..312afa89c10e61965626034deb066c1c04efafbe 100644
--- a/recipe_modules/raw_io/test_api.py
+++ b/recipe_modules/raw_io/test_api.py
@@ -7,19 +7,20 @@ from recipe_engine import recipe_test_api
 class RawIOTestApi(recipe_test_api.RecipeTestApi): # pragma: no cover
   @recipe_test_api.placeholder_step_data
   @staticmethod
-  def output(data, retcode=None):
-    return data, retcode
+  def output(data, retcode=None, name=None):
+    return data, retcode, name
 
   @recipe_test_api.placeholder_step_data
   @staticmethod
-  def output_dir(files_dict, retcode=None):
+  def output_dir(files_dict, retcode=None, name=None):
     assert type(files_dict) is dict
     assert all(type(key) is str for key in files_dict.keys())
     assert all(type(value) is str for value in files_dict.values())
-    return files_dict, retcode
+    return files_dict, retcode, name
 
-  def stream_output(self, data, stream='stdout', retcode=None):
+  def stream_output(self, data, stream='stdout', retcode=None, name=None):
     ret = recipe_test_api.StepTestData()
     assert stream in ('stdout', 'stderr')
-    setattr(ret, stream, self.output(data, retcode).unwrap_placeholder())
+    step_data = self.output(data, retcode=retcode, name=name)
+    setattr(ret, stream, step_data.unwrap_placeholder())
     return ret