diff --git a/tests/parse/templates.py b/tests/parse/templates.py
index d66d2e2..c108c1e 100644
--- a/tests/parse/templates.py
+++ b/tests/parse/templates.py
@@ -39,7 +39,7 @@
 # - The parse function generates the expected error
 # - The parse function uses the parse context as a parent
 def template_test_invalid(parser, context, tokens, expected):
-    stream = TokenStream(tokens)
+    stream = TokenStream(tokens.copy())
     error = None
     try:
         parsed = parser(stream, context)