1 files changed, 37 insertions, 0 deletions
diff --git a/js/src/tests/non262/Intl/NumberFormat/StringBuffer.js b/js/src/tests/non262/Intl/NumberFormat/StringBuffer.js
new file mode 100644
index 0000000000..70aaa7bd75
--- /dev/null
+++ b/js/src/tests/non262/Intl/NumberFormat/StringBuffer.js
@@ -0,0 +1,37 @@
+// |reftest| skip-if(!this.hasOwnProperty("Intl"))
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// The implementation of the format function uses the C++ StringBuffer class,
+// which changes its storage model at 32 characters, and uses it in a way which
+// also means that there's no room for null-termination at this limit.
+// This test makes sure that none of this affects the output.
+
+var format = new Intl.NumberFormat("it-IT", {minimumFractionDigits: 1});
+
+assertEq(format.format(1123123123123123123123.1), "1.123.123.123.123.123.100.000,0");
+assertEq(format.format(12123123123123123123123.1), "12.123.123.123.123.122.000.000,0");
+assertEq(format.format(123123123123123123123123.1), "123.123.123.123.123.120.000.000,0");
+
+// Ensure the ICU output matches Number.prototype.toFixed.
+function formatToFixed(x) {
+    var mfd = format.resolvedOptions().maximumFractionDigits;
+    var s = x.toFixed(mfd);
+
+    // To keep it simple we assume |s| is always in exponential form.
+    var m = s.match(/^(\d)\.(\d+)e\+(\d+)$/);
+    assertEq(m !== null, true);
+    s = m[1] + m[2].padEnd(m[3], "0");
+
+    // Group digits and append fractional part.
+    m = s.match(/\d{1,3}(?=(?:\d{3})*$)/g);
+    assertEq(m !== null, true);
+    return m.join(".") + ",0";
+}
+
+assertEq(formatToFixed(1123123123123123123123.1), "1.123.123.123.123.123.100.000,0");
+assertEq(formatToFixed(12123123123123123123123.1), "12.123.123.123.123.122.000.000,0");
+assertEq(formatToFixed(123123123123123123123123.1), "123.123.123.123.123.120.000.000,0");
+
+reportCompare(0, 0, "ok");