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diff --git a/js/src/tests/non262/Intl/variant-with-preferred-value.js b/js/src/tests/non262/Intl/variant-with-preferred-value.js
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+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+// Per UTS 35, computing the canonical form for Unicode BCP 47 locale identifiers
+// includes replacing deprecated variant mappings. The other UTS 35 canonicalisation
+// algorithm ("BCP 47 Language Tag to Unicode BCP 47 Locale Identifier") doesn't
+// support deprecated variant mappings.
+// https://github.com/tc39/ecma402/issues/330
+
+const languageTags = {
+    // The preferred value of "hy-arevela" is "hy" per CLDR.
+    "hy-arevela": "hy",
+    "hy-Armn-arevela": "hy-Armn",
+    "hy-AM-arevela": "hy-AM",
+    "hy-arevela-fonipa": "hy-fonipa",
+    "hy-fonipa-arevela": "hy-fonipa",
+
+    // The preferred value of "hy-arevmda" is "hyw" per CLDR.
+    "hy-arevmda": "hyw",
+    "hy-Armn-arevmda": "hyw-Armn",
+    "hy-AM-arevmda": "hyw-AM",
+    "hy-arevmda-fonipa": "hyw-fonipa",
+    "hy-fonipa-arevmda": "hyw-fonipa",
+
+    // The preferred value of "ja-Latn-hepburn-heploc" is "ja-Latn-alalc97" per CLDR and
+    // IANA.
+    "ja-Latn-hepburn-heploc": "ja-Latn-alalc97",
+    "ja-Latn-JP-hepburn-heploc": "ja-Latn-JP-alalc97",
+
+    // Variant subtag replacements not present in IANA.
+    "sv-aaland": "sv-AX",
+    "el-polytoni": "el-polyton",
+
+    // Additional cases when more variant subtags are present.
+
+    // 1. The preferred variant is already present.
+    "ja-Latn-alalc97-hepburn-heploc": "ja-Latn-alalc97",
+    "ja-Latn-hepburn-alalc97-heploc": "ja-Latn-alalc97",
+    "ja-Latn-hepburn-heploc-alalc97": "ja-Latn-alalc97",
+
+    // 2. The variant subtags aren't in the expected order per IANA. (CLDR doesn't care
+    //    about the order of variant subtags.)
+    "ja-Latn-heploc-hepburn": "ja-Latn-alalc97",
+
+    // 3. IANA expects both variant subtags to be present, CLDR also accepts single "heploc".
+    "ja-Latn-heploc": "ja-Latn-alalc97",
+
+    // 4. Test for cases when the same variant subtag position needs to be checked more
+    //    than once when replacing deprecated variant subtags.
+    "ja-Latn-aaland-heploc": "ja-Latn-AX-alalc97",
+    "ja-Latn-heploc-polytoni": "ja-Latn-alalc97-polyton",
+};
+
+for (let [tag, canonical] of Object.entries(languageTags)) {
+    assertEq(Intl.getCanonicalLocales(tag)[0], canonical);
+}
+
+if (typeof reportCompare === "function")
+    reportCompare(0, 0);