1 files changed, 17 insertions, 1 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
index 1dcdc7fb8a5..6217465ce7d 100644
--- a/components/script/dom/bindings/codegen/parser/tests/test_optional_constraints.py
+++ b/components/script/dom/bindings/codegen/parser/tests/test_optional_constraints.py
@@ -11,4 +11,20 @@ def WebIDLTest(parser, harness):
     except:
         threw = True
 
-    harness.ok(threw, "Should have thrown.")
+    harness.ok(not threw,
+               "Should not have thrown on non-optional argument following "
+               "optional argument.")
+
+    parser = parser.reset()
+    parser.parse("""
+        interface OptionalConstraints2 {
+          void foo(optional byte arg1 = 1, optional byte arg2 = 2,
+                   optional byte arg3, optional byte arg4 = 4,
+                   optional byte arg5, optional byte arg6 = 9);
+        };
+    """)
+    results = parser.finish()
+    args = results[0].members[0].signatures()[0][1]
+    harness.check(len(args), 6, "Should have 6 arguments")
+    harness.check(args[5].defaultValue.value, 9,
+                  "Should have correct default value")