diff --git a/tests/test_fields_mitigate_collision.py b/tests/test_fields_mitigate_collision.py
index 7830fcd9..a28d393e 100644
--- a/tests/test_fields_mitigate_collision.py
+++ b/tests/test_fields_mitigate_collision.py
@@ -31,5 +31,6 @@ class TestMessage(proto.Message):
     obj.eggs = "has_eggs"
     assert obj.spam_ == "has_spam"
 
+    # Test that `spam` is coerced to `spam_`
     modified_obj = TestMessage({"spam": "has_spam", "eggs": "has_eggs"})
     assert modified_obj.spam_ == "has_spam"