3 files changed, 108 insertions, 0 deletions
diff --git a/modules/libpref/test/browser/browser.ini b/modules/libpref/test/browser/browser.ini
new file mode 100644
index 0000000000..f657000718
--- /dev/null
+++ b/modules/libpref/test/browser/browser.ini
@@ -0,0 +1,9 @@
+[DEFAULT]
+
+support-files =
+  file_access_sanitized_pref.html
+
+[browser_sanitization_events.js]
+skip-if = ccov
+          tsan
+          (os == 'linux' && asan)
diff --git a/modules/libpref/test/browser/browser_sanitization_events.js b/modules/libpref/test/browser/browser_sanitization_events.js
new file mode 100644
index 0000000000..f71bd04879
--- /dev/null
+++ b/modules/libpref/test/browser/browser_sanitization_events.js
@@ -0,0 +1,89 @@
+"use strict";
+
+const { TelemetryTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/TelemetryTestUtils.sys.mjs"
+);
+
+// eslint-disable-next-line
+const ROOT = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content",
+  "https://example.com"
+);
+const PAGE_URL = ROOT + "file_access_sanitized_pref.html";
+
+async function waitForEventCount(
+  count,
+  process = "content",
+  category = "security",
+  method = "prefUsage"
+) {
+  // eslint-disable-next-line mozilla/no-arbitrary-setTimeout
+  await new Promise(resolve => setTimeout(resolve, 100));
+  let returned_events = await TestUtils.waitForCondition(() => {
+    let events = Services.telemetry.snapshotEvents(
+      Ci.nsITelemetry.DATASET_PRERELEASE_CHANNELS,
+      false
+    )[process];
+
+    if (!events) {
+      return null;
+    }
+
+    events = events.filter(e => e[1] == category && e[2] == method);
+    dump(`Waiting for ${count} events, got ${events.length}\n`);
+    return events.length >= count ? events : null;
+  }, "waiting for telemetry event count of: " + count);
+  return returned_events;
+}
+
+add_task(async function sanitized_pref_test() {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["fission.omitBlocklistedPrefsInSubprocesses", true],
+      ["fission.enforceBlocklistedPrefsInSubprocesses", false],
+    ],
+  });
+
+  Services.telemetry.setEventRecordingEnabled("security", true);
+  Services.telemetry.clearEvents();
+
+  TelemetryTestUtils.assertNumberOfEvents(0, { process: "content" });
+
+  await BrowserTestUtils.withNewTab(
+    { gBrowser, url: PAGE_URL },
+    async function (browser) {}
+  );
+
+  // Needed because otherwise we advance too quickly
+  await waitForEventCount(1);
+
+  let events = TelemetryTestUtils.getEvents(
+    { category: "security", method: "prefUsage", object: "contentProcess" },
+    { process: "content" }
+  );
+
+  let count = 0,
+    foundIt = false;
+  for (let i = 0; i < events.length; i++) {
+    if (events[i].value == "extensions.webextensions.uuids") {
+      foundIt = true;
+      count++;
+    }
+  }
+
+  // We may have more than one event entries because we take two paths in the preference code
+  // in this access pattern, but in other patterns we may only take one of those
+  // paths, so we happen to count it twice this way.  No big deal. Sometimes we even have 4
+  // or 6 based on timing
+  dump(
+    `We found ${events.length} events, ${count} of which were 'extensions.webextensions.uuids'.`
+  );
+
+  // eslint-disable-next-line
+  Assert.ok(
+    foundIt,
+    "We did not find an event for 'extensions.webextensions.uuids'"
+  );
+
+  await SpecialPowers.popPrefEnv();
+});
diff --git a/modules/libpref/test/browser/file_access_sanitized_pref.html b/modules/libpref/test/browser/file_access_sanitized_pref.html
new file mode 100644
index 0000000000..ae21abb2ad
--- /dev/null
+++ b/modules/libpref/test/browser/file_access_sanitized_pref.html
@@ -0,0 +1,10 @@
+
+
+<!DOCTYPE HTML>
+<html>
+<body>
+	<script>
+	  SpecialPowers.getCharPref("extensions.webextensions.uuids", "<na>");
+	</script>
+</body>
+</html>