1 files changed, 69 insertions, 0 deletions
diff --git a/js/src/tests/non262/Set/is-subset-of.js b/js/src/tests/non262/Set/is-subset-of.js
new file mode 100644
index 0000000000..b6c74126b6
--- /dev/null
+++ b/js/src/tests/non262/Set/is-subset-of.js
@@ -0,0 +1,69 @@
+/*
+ * Any copyright is dedicated to the Public Domain.
+ * https://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+if (typeof getBuildConfiguration === "undefined") {
+    var getBuildConfiguration = SpecialPowers.Cu.getJSTestingFunctions().getBuildConfiguration;
+}
+
+if (typeof getRealmConfiguration === "undefined") {
+    var getRealmConfiguration = SpecialPowers.Cu.getJSTestingFunctions().getRealmConfiguration;
+}
+
+if (getBuildConfiguration()['new-set-methods'] && getRealmConfiguration().enableNewSetMethods) {
+
+    assertEq(typeof Set.prototype.isSubsetOf, 'function');
+    assertEq(Set.prototype.isSubsetOf.length, 1);
+    assertEq(Set.prototype.isSubsetOf.name, 'isSubsetOf');
+
+    assertEq(new Set([1, true, null]).isSubsetOf(new Set()), false);
+
+    assertEq(new Set([1, true, null]).isSubsetOf([1, true, null]), true);
+    assertEq(new Set([1, 2, 3]).isSubsetOf([2, 3, 4]), false);
+    assertEq(new Set([1, 2, 3]).isSubsetOf([1, 2, 3, 4]), true);
+    // Works when the argument is a custom iterable which follows the Symbol.iterator protocol
+    assertEq(new Set([1, 2, 3]).isSubsetOf(makeArrayIteratorWithHasMethod([3, 4])), false);
+
+    // Works when the `this` is a custom iterable which follows the Symbol.iterator protocol
+    assertEq(
+        Set.prototype.isSubsetOf.call(
+            makeArrayIteratorWithHasMethod([1, 2, 3, 3, 2]),
+            makeArrayIteratorWithHasMethod([4, 5, 6])
+        ),
+        false
+    );
+
+    // Does not modify the original set object
+    const set = new Set([1]);
+    assertEq(set.isSubsetOf(new Set([2])) !== set, true);
+
+    // Argument must be iterable and an object
+    assertThrowsInstanceOf(function () {
+        const set = new Set();
+        set.isSubsetOf();
+    }, TypeError);
+    for (const arg of [null, {}, true, 1, undefined, NaN, Symbol(), ""]) {
+        assertThrowsInstanceOf(function () {
+            const set = new Set();
+            set.isSubsetOf(arg);
+        }, TypeError);
+    }
+
+    // `this` must be an Object
+    for (const arg of [null, undefined, Symbol()]) {
+        assertThrowsInstanceOf(function () {
+            Set.prototype.isSubsetOf.call(arg, []);
+        }, TypeError);
+    }
+
+    // `this` must be iterable
+    assertThrowsInstanceOf(function () {
+        Set.prototype.isSubsetOf.call({}, []);
+    }, TypeError);
+} else {
+    assertEq(typeof Set.prototype.isSubsetOf, 'undefined');
+}
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);