Merge remote-tracking branch 'ms2ger/rtf-formatToParts-type'

* ms2ger/rtf-formatToParts-type:
  Intl.RelativeTimeFormat: Add tests for the type of formatToParts results.

test/intl402/RelativeTimeFormat/prototype/formatToParts/result-type.js

+// Copyright 2018 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-Intl.RelativeTimeFormat.prototype.formatToParts
+description: Checks the handling of plural unit arguments to Intl.RelativeTimeFormat.prototype.formatToParts().
+info: |
+    FormatRelativeTimeToParts ( relativeTimeFormat, value, unit )
+
+    3. Let n be 0.
+    4. For each part in parts, do:
+        a. Let O be ObjectCreate(%ObjectPrototype%).
+        b. Perform ! CreateDataPropertyOrThrow(O, "type", part.[[Type]]).
+        c. Perform ! CreateDataPropertyOrThrow(O, "value", part.[[Value]]).
+        d. If part has a [[Unit]] field,
+            i. Perform ! CreateDataPropertyOrThrow(O, "unit", part.[[Unit]]).
+        e. Perform ! CreateDataPropertyOrThrow(result, ! ToString(n), O).
+        f. Increment n by 1.
+
+features: [Intl.RelativeTimeFormat]
+includes: [propertyHelper.js]
+---*/
+
+const rtf = new Intl.RelativeTimeFormat("en-US");
+
+assert.sameValue(typeof rtf.formatToParts, "function", "formatToParts should be supported");
+
+const parts = rtf.formatToParts(3, "second");
+
+assert.sameValue(Object.getPrototypeOf(parts), Array.prototype, "parts: prototype");
+assert.sameValue(Array.isArray(parts), true, "parts: isArray");
+assert.sameValue(parts.length, 3, "parts: length");
+
+assert.sameValue(Object.getPrototypeOf(parts[0]), Object.prototype, "parts[0]: prototype");
+verifyProperty(parts[0], "type", {
+  value: "literal",
+  writable: true,
+  enumerable: true,
+  configurable: true,
+});
+verifyProperty(parts[0], "value", {
+  value: "in ",
+  writable: true,
+  enumerable: true,
+  configurable: true,
+});
+
+
+assert.sameValue(Object.getPrototypeOf(parts[1]), Object.prototype, "parts[1]: prototype");
+verifyProperty(parts[1], "type", {
+  value: "integer",
+  writable: true,
+  enumerable: true,
+  configurable: true,
+});
+verifyProperty(parts[1], "value", {
+  value: "3",
+  writable: true,
+  enumerable: true,
+  configurable: true,
+});
+verifyProperty(parts[1], "unit", {
+  value: "second",
+  writable: true,
+  enumerable: true,
+  configurable: true,
+});
+
+
+assert.sameValue(Object.getPrototypeOf(parts[2]), Object.prototype, "parts[2]: prototype");
+verifyProperty(parts[2], "type", {
+  value: "literal",
+  writable: true,
+  enumerable: true,
+  configurable: true,
+});
+verifyProperty(parts[2], "value", {
+  value: " seconds",
+  writable: true,
+  enumerable: true,
+  configurable: true,
+});