1 files changed, 16 insertions, 0 deletions
diff --git a/third_party/WebIDL/tests/test_double_null.py b/third_party/WebIDL/tests/test_double_null.py
new file mode 100644
index 00000000000..a8876a7fd2d
--- /dev/null
+++ b/third_party/WebIDL/tests/test_double_null.py
@@ -0,0 +1,16 @@
+def WebIDLTest(parser, harness):
+    threw = False
+    try:
+        parser.parse(
+            """
+            interface DoubleNull {
+              attribute byte?? foo;
+            };
+        """
+        )
+
+        results = parser.finish()
+    except:
+        threw = True
+
+    harness.ok(threw, "Should have thrown.")