1 files changed, 18 insertions, 0 deletions
diff --git a/browser/components/resistfingerprinting/test/mochitest/test_iframe.html b/browser/components/resistfingerprinting/test/mochitest/test_iframe.html
new file mode 100644
index 0000000000..f01809b28c
--- /dev/null
+++ b/browser/components/resistfingerprinting/test/mochitest/test_iframe.html
@@ -0,0 +1,18 @@
+<!doctype html>
+<script src="/tests/SimpleTest/SimpleTest.js"></script>
+<link rel="stylesheet" href="/tests/SimpleTest/test.css"/>
+<body>
+<script>
+  add_task(async function() {
+    await SpecialPowers.pushPrefEnv({
+      "set": [["privacy.resistFingerprinting", true]],
+    });
+    is(screen.width, window.innerWidth, "Width should be spoofed");
+    is(screen.height, window.innerHeight, "Height should be spoofed");
+    let iframe = document.createElement("iframe");
+    document.body.appendChild(iframe);
+    is(iframe.contentWindow.screen.width, iframe.contentWindow.innerWidth, "Width should be spoofed in iframe");
+    is(iframe.contentWindow.screen.height, iframe.contentWindow.innerHeight, "Height should be spoofed in iframe");
+  });
+</script>
+</body>