diff --git a/browser/components/resistfingerprinting/test/mochitest/mochitest.ini b/browser/components/resistfingerprinting/test/mochitest/mochitest.ini
index d108c764d1cf27549c3d9cbee3bee5fd8b52cf9b..55a5db7753022da5ad8a93331cd732f00981ac88 100644
--- a/browser/components/resistfingerprinting/test/mochitest/mochitest.ini
+++ b/browser/components/resistfingerprinting/test/mochitest/mochitest.ini
@@ -1,5 +1,6 @@
[DEFAULT]
tags = resistfingerprinting
+
support-files =
worker_child.js
worker_grandchild.js
@@ -13,3 +14,4 @@ scheme = https
support-files = test_hide_gamepad_info_iframe.html
[test_speech_synthesis.html]
[test_bug1382499_touch_api.html]
+[test_bug863246_resource_uri.html]
diff --git a/browser/components/resistfingerprinting/test/mochitest/test_bug863246_resource_uri.html b/browser/components/resistfingerprinting/test/mochitest/test_bug863246_resource_uri.html
new file mode 100644
index 0000000000000000000000000000000000000000..13dad300ff055f900d9e285f9d441e417c0f2865
--- /dev/null
+++ b/browser/components/resistfingerprinting/test/mochitest/test_bug863246_resource_uri.html
@@ -0,0 +1,51 @@
+<!DOCTYPE html>
+<meta charset="utf8">
+<script src="/tests/SimpleTest/SimpleTest.js"></script>
+<script src="/tests/SimpleTest/SpawnTask.js"></script>
+<script>
+/* global SimpleTest SpecialPowers add_task */
+
+function waitForDOMContentLoaded() {
+ return new Promise((aResolve) => {
+ document.addEventListener("DOMContentLoaded", aResolve);
+ });
+}
+
+function testResourceUri(aTest, aUri, aContentAccessible) {
+ return new Promise((aResolve) => {
+ let link = document.createElement("link");
+ link.rel = "stylesheet";
+ link.onload = () => {
+ SimpleTest.ok(aContentAccessible, aTest);
+ aResolve();
+ };
+ link.onerror = () => {
+ SimpleTest.ok(!aContentAccessible, aTest);
+ aResolve();
+ };
+ link.href = aUri;
+ document.head.appendChild(link);
+ });
+}
+
+add_task(async function() {
+ await waitForDOMContentLoaded();
+ await testResourceUri(
+ "resource://content-accessible is content-accessible",
+ "resource://content-accessible/viewsource.css",
+ true);
+ await testResourceUri(
+ "resource://gre-resources is not content-accessible",
+ "resource://gre-resources/html.css",
+ false);
+ await SpecialPowers.pushPrefEnv({
+ set: [
+ ["security.all_resource_uri_content_accessible", true]
+ ]
+ });
+ await testResourceUri(
+ "security.all_resource_uri_content_accessible = true, resource://gre-resources is now content-accessible",
+ "resource://gre-resources/html.css",
+ true);
+});
+</script>