1 files changed, 72 insertions, 0 deletions
diff --git a/js/src/tests/test262/intl402/Segmenter/prototype/segment/containing/zero-index.js b/js/src/tests/test262/intl402/Segmenter/prototype/segment/containing/zero-index.js
new file mode 100644
index 0000000000..0e768bd224
--- /dev/null
+++ b/js/src/tests/test262/intl402/Segmenter/prototype/segment/containing/zero-index.js
@@ -0,0 +1,72 @@
+// |reftest| skip-if(!Intl.Segmenter) -- Intl.Segmenter is not enabled unconditionally
+// Copyright 2020 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-%segmentsprototype%.containing
+description: Verifies the cases which the value of index turn into 0.
+info: |
+    %Segments.prototype%.containing ( index )
+
+    6. Let n be ? ToInteger(index).
+    7. If n < 0 or n ≥ len, return undefined.
+    8. Let startIndex be ! FindBoundary(segmenter, string, n, before).
+
+    ToInteger ( argument )
+    1. Let number be ? ToNumber(argument).
+    2. If number is NaN, +0, or -0, return +0.
+    4. Let integer be the Number value that is the same sign as number and whose magnitude is floor(abs(number)).
+    5. If integer is -0, return +0.
+    6. Return integer.
+
+    ToNumber ( argument )
+    Undefined | Return NaN.
+    Null      | Return +0.
+    Boolean   | If argument is true, return 1. If argument is false, return +0.
+
+features: [Intl.Segmenter]
+---*/
+
+const input = "a b c";
+const granularities = [undefined, "grapheme", "word", "sentence"];
+const index_to_zeros = [
+    0,
+    -0,
+    NaN,
+    0.49,
+    -0.49,
+    null,
+    undefined,
+    false,
+    "\ud800\udc00", // surrogate
+    "\ud800", // only leading surrogate
+    "\udc00", // only trailing surrogate
+    "a",
+    "g",
+    "\u00DD",
+    "0",
+    "+0",
+    "-0",
+    "0.49",
+    "+0.49",
+    "-0.49",
+    "4.9e-1",
+    "-4.9e-1",
+    "4.9E-1",
+    "-4.9E-1",
+    { toString(){ return "-0.1"; } },
+    { valueOf(){ return 0.1; } },
+    { [Symbol.toPrimitive](){ return -0.1; } },
+];
+
+granularities.forEach(
+    function(granularity) {
+      const segmenter = new Intl.Segmenter(undefined, {granularity});
+      const segment = segmenter.segment(input);
+      index_to_zeros.forEach(function(index) {
+        const result = segment.containing(index);
+        assert.sameValue(0, result.index);
+        assert.sameValue(input, result.input);
+      });
+    });
+
+reportCompare(0, 0);