1 files changed, 17 insertions, 0 deletions
diff --git a/dom/bindings/parser/tests/test_deduplicate.py b/dom/bindings/parser/tests/test_deduplicate.py
new file mode 100644
index 0000000000..2308f6201e
--- /dev/null
+++ b/dom/bindings/parser/tests/test_deduplicate.py
@@ -0,0 +1,17 @@
+def WebIDLTest(parser, harness):
+    parser.parse(
+        """
+        interface Foo;
+        interface Bar;
+        interface Foo;
+        """
+    )
+
+    results = parser.finish()
+
+    # There should be no duplicate interfaces in the result.
+    expectedNames = sorted(["Foo", "Bar"])
+    actualNames = sorted(map(lambda iface: iface.identifier.name, results))
+    harness.check(
+        actualNames, expectedNames, "Parser shouldn't output duplicate names."
+    )