Whitelist allowed test names

recipe_engine/recipe_test_api.py

Index: recipe_engine/recipe_test_api.py
diff --git a/recipe_engine/recipe_test_api.py b/recipe_engine/recipe_test_api.py
index e9e0431d86c7a4a68f8649ee32ff4315d0dbe768..d4186fb2af50f626863c37061d9953fb52dbf365 100644
--- a/recipe_engine/recipe_test_api.py
+++ b/recipe_engine/recipe_test_api.py
@@ -4,6 +4,7 @@
 
 import contextlib
 import inspect
+import re
 
 from collections import namedtuple, defaultdict
 
@@ -187,9 +188,18 @@ PostprocessHook = namedtuple(
   'PostprocessHook', 'func args kwargs filename lineno')
 
 
+def is_valid_test_name(name):
+  return bool(re.match(r'^(\w)+$', name))
+
+
 class TestData(BaseTestData):
   def __init__(self, name=None):
     super(TestData, self).__init__()
+    # Allow empty names; sometimes we create test datas to merge two test datas
+    # together.
+    if name and not is_valid_test_name(name):
+      raise ValueError("Invalid test name %r" % name)
+
     self.name = name
     self.properties = {}  # key -> val
     self.mod_data = defaultdict(ModuleTestData)