--- a/browser/components/resistfingerprinting/test/browser/browser.ini
+++ b/browser/components/resistfingerprinting/test/browser/browser.ini
@@ -1,12 +1,13 @@
 [DEFAULT]
 tags = resistfingerprinting
 support-files =
   file_dummy.html
+  file_workerPerformance.js
   head.js
 
 [browser_performanceAPI.js]
 [browser_roundedWindow_dialogWindow.js]
 [browser_roundedWindow_newWindow.js]
 [browser_roundedWindow_open_max.js]
 [browser_roundedWindow_open_mid.js]
 [browser_roundedWindow_open_min.js]

--- a/browser/components/resistfingerprinting/test/browser/browser_performanceAPI.js
+++ b/browser/components/resistfingerprinting/test/browser/browser_performanceAPI.js
@@ -24,21 +24,23 @@ const PERFORMANCE_TIMINGS = [
   "domInteractive",
   "domContentLoadedEventStart",
   "domContentLoadedEventEnd",
   "domComplete",
   "loadEventStart",
   "loadEventEnd",
 ];
 
-add_task(async function runTests() {
+add_task(async function setup() {
   await SpecialPowers.pushPrefEnv({"set":
     [["privacy.resistFingerprinting", true]]
   });
+});
 
+add_task(async function runTests() {
   let tab = await BrowserTestUtils.openNewForegroundTab(
     gBrowser, TEST_PATH + "file_dummy.html");
 
   await ContentTask.spawn(tab.linkedBrowser, PERFORMANCE_TIMINGS, async function(list) {
     // Check that whether the performance timing API is correctly spoofed.
     for (let time of list) {
       is(content.performance.timing[time], 0, `The timing(${time}) is correctly spoofed.`);
     }
@@ -52,8 +54,32 @@ add_task(async function runTests() {
     is(content.performance.getEntries().length, 0, "No entries for performance.getEntries()");
     is(content.performance.getEntriesByType("resource").length, 0, "No entries for performance.getEntriesByType()");
     is(content.performance.getEntriesByName("Test", "mark").length, 0, "No entries for performance.getEntriesByName()");
 
   });
 
   await BrowserTestUtils.removeTab(tab);
 });
+
+add_task(async function runTestsForWorker() {
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser, TEST_PATH + "file_dummy.html");
+
+  await ContentTask.spawn(tab.linkedBrowser, null, async function() {
+    await new Promise(resolve => {
+      let worker = new content.Worker("file_workerPerformance.js");
+      worker.onmessage = function(e) {
+        if (e.data.type == "status") {
+          ok(e.data.status, e.data.msg);
+        } else if (e.data.type == "finish") {
+          resolve();
+        } else {
+          ok(false, "Unknown message type");
+          resolve();
+        }
+      }
+      worker.postMessage({type: "runTests"});
+    });
+  });
+
+  await BrowserTestUtils.removeTab(tab);
+});

new file mode 100644
--- /dev/null
+++ b/browser/components/resistfingerprinting/test/browser/file_workerPerformance.js
@@ -0,0 +1,33 @@
+function ok(a, msg) {
+  postMessage({type: "status", status: !!a, msg});
+}
+
+function is(a, b, msg) {
+  ok(a === b, msg);
+}
+
+function finish() {
+  postMessage({type: "finish"});
+}
+
+function runTests() {
+  // Try to add some entries.
+  performance.mark("Test");
+  performance.mark("Test-End");
+  performance.measure("Test-Measure", "Test", "Test-End");
+
+  // Check that no entries for performance.getEntries/getEntriesByType/getEntriesByName.
+  is(performance.getEntries().length, 0, "No entries for performance.getEntries() for workers");
+  is(performance.getEntriesByType("resource").length, 0, "No entries for performance.getEntriesByType() for workers");
+  is(performance.getEntriesByName("Test", "mark").length, 0, "No entries for performance.getEntriesByName() for workers");
+
+  finish();
+}
+
+self.onmessage = function(e) {
+  if (e.data.type === "runTests") {
+    runTests();
+  } else {
+    ok(false, "Unknown message type");
+  }
+}