1 files changed, 65 insertions, 0 deletions
diff --git a/js/src/tests/non262/Set/union.js b/js/src/tests/non262/Set/union.js
new file mode 100644
index 0000000000..c7cf8026e5
--- /dev/null
+++ b/js/src/tests/non262/Set/union.js
@@ -0,0 +1,65 @@
+/*
+ * 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.union, 'function');
+    assertEq(Set.prototype.union.length, 1);
+    assertEq(Set.prototype.union.name, 'union');
+
+    assertSetContainsExactOrderedItems(new Set([1, true, null]).union(new Set()), [1, true, null]);
+    assertSetContainsExactOrderedItems(new Set([1, true, null]).union([1, true, null]), [1, true, null]);
+    assertSetContainsExactOrderedItems(new Set([1, 2, 3]).union([2, 3, 4]), [1, 2, 3, 4]);
+    assertSetContainsExactOrderedItems(new Set([1, 2, 3]).union([4]), [1, 2, 3, 4]);
+    // Works when the argument is a custom iterable which follows the Symbol.iterator protocol
+    assertSetContainsExactOrderedItems(new Set([1, 2, 3]).union(makeArrayIterator([3, 4])), [1, 2, 3, 4]);
+    assertSetContainsExactOrderedItems(new Set(['a']).union('abc'), ['a', 'b', 'c']);
+
+    // Works when the `this` is a custom iterable which follows the Symbol.iterator protocol
+    assertSetContainsExactOrderedItems(Set.prototype.union.call(makeArrayIterator([1, 2, 3, 3, 2]), [4, 5, 6]), [1, 2, 3, 4, 5, 6]);
+
+    // Does not modify the original set object
+    const set = new Set([1]);
+    assertEq(set.union([2]) !== set, true);
+
+    // Argument must be iterable
+    assertThrowsInstanceOf(function () {
+        const set = new Set();
+        set.union();
+    }, TypeError);
+    for (const arg of [null, {}, true, 1, undefined, NaN, Symbol()]) {
+        assertThrowsInstanceOf(function () {
+            const set = new Set();
+            set.union(arg);
+        }, TypeError);
+    }
+
+    // `this` must be an Object
+    for (const arg of [null, undefined, Symbol()]) {
+        assertThrowsInstanceOf(function () {
+            Set.prototype.union.call(arg, []);
+        }, TypeError);
+    }
+
+    // `this` must be iterable
+    assertThrowsInstanceOf(function () {
+        Set.prototype.union.call({}, []);
+    }, TypeError);
+} else {
+    assertEq(typeof Set.prototype.union, 'undefined');
+}
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);