1 files changed, 25 insertions, 0 deletions
diff --git a/js/src/tests/test262/language/module-code/early-dup-assert-key-export.js b/js/src/tests/test262/language/module-code/early-dup-assert-key-export.js
new file mode 100644
index 0000000000..a2be110bf0
--- /dev/null
+++ b/js/src/tests/test262/language/module-code/early-dup-assert-key-export.js
@@ -0,0 +1,25 @@
+// |reftest| shell-option(--enable-import-assertions) skip-if(!xulRuntime.shell) error:SyntaxError module -- requires shell-options
+// Copyright (C) 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+description: AssertClause may not have duplicate keys (export declaration)
+esid: sec-modules
+info: |
+  AssertClause:assert{AssertEntries,opt}
+
+  - It is a Syntax Error if AssertClauseToAssertions of AssertClause has two
+    entries a and b such that a.[[Key]] is b.[[Key]].
+features: [import-assertions]
+flags: [module]
+negative:
+  phase: parse
+  type: SyntaxError
+---*/
+
+$DONOTEVALUATE();
+
+export * from './import-assertion-3_FIXTURE.js' assert {
+  test262_a: '',
+  test262_b: '',
+  'test262_\u0061': ''
+};