Add missing regression test for #561

Author: fatso83

package.json

@@ -83,6 +83,7 @@
     ]
   },
   "browser": {
+    "vm": false,
     "node:timers": false,
     "node:timers/promises": false,
     "timers": false,

test/issue-561-test.js

@@ -0,0 +1,35 @@
+"use strict";
+
+const vm = require("vm");
+const { FakeTimers, assert, refute } = require("./helpers/setup-tests");
+
+describe("issue #561 - cross-realm Date passed to setSystemTime", function () {
+    let clock;
+
+    before(function () {
+        if (typeof vm.runInNewContext !== "function") {
+            this.skip();
+        }
+    });
+
+    afterEach(function () {
+        if (clock) {
+            clock.uninstall();
+            clock = undefined;
+        }
+    });
+
+    it("accepts a Date from another realm", function () {
+        clock = FakeTimers.install();
+        const crossRealmDate = vm.runInNewContext(
+            "new Date('2026-04-02T00:00:00.000Z')",
+        );
+
+        refute.exception(function () {
+            clock.setSystemTime(crossRealmDate);
+        });
+
+        assert.same(clock.now, crossRealmDate.getTime());
+        assert.same(new Date().getTime(), crossRealmDate.getTime());
+    });
+});