1 files changed, 63 insertions, 0 deletions
diff --git a/js/src/tests/non262/Set/difference.js b/js/src/tests/non262/Set/difference.js
new file mode 100644
index 0000000000..edcaec7608
--- /dev/null
+++ b/js/src/tests/non262/Set/difference.js
@@ -0,0 +1,63 @@
+/*
+ * 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.difference, 'function');
+    assertEq(Set.prototype.difference.length, 1);
+    assertEq(Set.prototype.difference.name, 'difference');
+
+    assertSetContainsExactOrderedItems(new Set([1, true, null]).difference(new Set()), [1, true, null]);
+    assertSetContainsExactOrderedItems(new Set([1, true, null]).difference([1, true, null]), []);
+    assertSetContainsExactOrderedItems(new Set([1, 2, 3]).difference([2, 3, 4]), [1]);
+    assertSetContainsExactOrderedItems(new Set([1, 2, 3]).difference([4]), [1, 2, 3]);
+    // Works when the argument is a custom iterable which follows the Symbol.iterator protocol
+    assertSetContainsExactOrderedItems(new Set([1, 2, 3]).difference(makeArrayIterator([3, 4])), [1, 2]);
+    assertSetContainsExactOrderedItems(new Set(['a','d']).difference('abc'), ['d']);
+
+    // Works when the `this` is a custom iterable which follows the Symbol.iterator protocol
+    assertSetContainsExactOrderedItems(Set.prototype.difference.call(makeArrayIterator([1, 2, 3, 3, 2]), [4, 5, 6]), [1, 2, 3]);
+
+    // Does not modify the original set object
+    const set = new Set([1]);
+    assertEq(set.difference([1]) !== set, true);
+
+    // Argument must be iterable
+    assertThrowsInstanceOf(function () {
+        const set = new Set();
+        set.difference();
+    }, TypeError);
+    for (const arg of [null, {}, true, 1, undefined, NaN, Symbol()]) {
+        assertThrowsInstanceOf(function () {
+            const set = new Set();
+            set.difference(arg);
+        }, TypeError);
+    }
+
+    // `this` must be an Object
+    for (const arg of [null, undefined, Symbol()]) {
+        assertThrowsInstanceOf(function () {
+            Set.prototype.difference.call(arg, []);
+        }, TypeError);
+    }
+
+    // `this` must be iterable
+    assertThrowsInstanceOf(function () {
+        Set.prototype.difference.call({}, []);
+    }, TypeError);
+} else {
+    assertEq(typeof Set.prototype.difference, 'undefined');
+}
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);