1 files changed, 47 insertions, 0 deletions
diff --git a/js/src/tests/non262/Intl/tolower-ascii-equivalent.js b/js/src/tests/non262/Intl/tolower-ascii-equivalent.js
new file mode 100644
index 0000000000..ac3cbfb7d3
--- /dev/null
+++ b/js/src/tests/non262/Intl/tolower-ascii-equivalent.js
@@ -0,0 +1,47 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+
+// Language tags are processed case-insensitive, but unconditionally calling
+// the built-in String.prototype.toLowerCase() or toUpperCase() function
+// before parsing a language tag can map non-ASCII characters into the ASCII
+// range.
+//
+// Validate the Unicode BCP 47 locale identifier parser handles this case
+// (pun intended) correctly by passing language tags which contain
+// U+212A (KELVIN SIGN) and U+0131 (LATIN SMALL LETTER DOTLESS I) to
+// Intl.getCanonicalLocales().
+
+// The lower-case form of "i-ha\u212A" is "i-hak".
+assertEq("i-hak", "i-ha\u212A".toLowerCase());
+
+// The upper-case form of "\u0131-hak" is "I-HAK".
+assertEq("I-HAK", "\u0131-hak".toUpperCase());
+
+// "i-hak" is not a valid Unicode BCP 47 locale identifier.
+assertThrowsInstanceOf(() => Intl.getCanonicalLocales("i-hak"), RangeError);
+
+// And neither is "i-ha\u212A".
+assertThrowsInstanceOf(() => Intl.getCanonicalLocales("i-ha\u212A"), RangeError);
+
+// And also "\u0131-hak" isn't valid.
+assertThrowsInstanceOf(() => Intl.getCanonicalLocales("\u0131-hak"), RangeError);
+
+// The lower-case form of "zh-ha\u212A\u212Aa" is "zh-hakka".
+assertEq("zh-hakka", "zh-ha\u212A\u212Aa".toLowerCase());
+
+// "zh-hakka" is a valid Unicode BCP 47 locale identifier.
+assertEqArray(Intl.getCanonicalLocales("zh-hakka"), ["hak"]);
+
+// But "zh-ha\u212A\u212Aa" is not a valid locale identifier.
+assertThrowsInstanceOf(() => Intl.getCanonicalLocales("zh-ha\u212A\u212Aa"), RangeError);
+
+// The lower-case form of "zh-x\u0131ang" is "ZH-XIANG".
+assertEq("ZH-XIANG", "zh-x\u0131ang".toUpperCase());
+
+// "zh-xiang" is a valid Unicode BCP 47 locale identifier.
+assertEqArray(Intl.getCanonicalLocales("zh-xiang"), ["hsn"]);
+
+// But "zh-x\u0131ang" is not a valid locale identifier.
+assertThrowsInstanceOf(() => Intl.getCanonicalLocales("zh-x\u0131ang"), RangeError);
+
+if (typeof reportCompare === 'function')
+    reportCompare(0, 0);