improve unicode support

recipe_engine/third_party/expect_tests/serialize.py

Index: recipe_engine/third_party/expect_tests/serialize.py
diff --git a/recipe_engine/third_party/expect_tests/serialize.py b/recipe_engine/third_party/expect_tests/serialize.py
index 7324a47b9d1a006a7051f4cef97c47e05e2be6b6..95d17ffd8e88180a9d181cc3dd6b96f45a21980e 100644
--- a/recipe_engine/third_party/expect_tests/serialize.py
+++ b/recipe_engine/third_party/expect_tests/serialize.py
@@ -28,8 +28,8 @@ def re_encode(obj):
     return {re_encode(k): re_encode(v) for k, v in obj.iteritems()}
   elif isinstance(obj, list):
     return [re_encode(i) for i in obj]
-  elif isinstance(obj, unicode):
-    return obj.encode('utf-8')
+  elif isinstance(obj, str):
+    return obj.decode('utf-8')
   else:
     return obj