1 files changed, 14 insertions, 0 deletions
diff --git a/components/script/dom/bindings/codegen/parser/tests/test_optional_constraints.py b/components/script/dom/bindings/codegen/parser/tests/test_optional_constraints.py
new file mode 100644
index 00000000000..1dcdc7fb8a5
--- /dev/null
+++ b/components/script/dom/bindings/codegen/parser/tests/test_optional_constraints.py
@@ -0,0 +1,14 @@
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse("""
+            interface OptionalConstraints1 {
+              void foo(optional byte arg1, byte arg2);
+            };
+        """)
+
+        results = parser.finish()
+    except:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")