diff --git a/browser/components/resistfingerprinting/test/browser/browser.ini b/browser/components/resistfingerprinting/test/browser/browser.ini
index 05801c9c19bb..5f7fda69b1f7 100644
--- a/browser/components/resistfingerprinting/test/browser/browser.ini
+++ b/browser/components/resistfingerprinting/test/browser/browser.ini
@@ -2,9 +2,12 @@
 tags = resistfingerprinting
 support-files =
   file_dummy.html
+  file_navigator.html
+  file_navigatorWorker.js
   file_workerPerformance.js
   head.js
 
+[browser_navigator.js]
 [browser_performanceAPI.js]
 [browser_roundedWindow_dialogWindow.js]
 [browser_roundedWindow_newWindow.js]
diff --git a/browser/components/resistfingerprinting/test/browser/browser_navigator.js b/browser/components/resistfingerprinting/test/browser/browser_navigator.js
new file mode 100644
index 000000000000..6a67d7a84baa
--- /dev/null
+++ b/browser/components/resistfingerprinting/test/browser/browser_navigator.js
@@ -0,0 +1,122 @@
+/**
+ * Bug 1333651 - A test case for making sure the navigator object has been
+ *   spoofed/disabled correctly.
+ */
+
+const { classes: Cc, Constructor: CC, interfaces: Ci, utils: Cu } = Components;
+
+const TEST_PATH = "http://example.net/browser/browser/" +
+                  "components/resistfingerprinting/test/browser/"
+
+var spoofedUserAgent;
+
+const SPOOFED_APPNAME        = "Netscape";
+const SPOOFED_APPVERSION     = "5.0 (Windows)";
+const SPOOFED_PLATFORM       = "Win32";
+const SPOOFED_OSCPU          = "Windows NT 6.1";
+const SPOOFED_BUILDID        = "20100101";
+const SPOOFED_HW_CONCURRENCY = 2;
+
+const CONST_APPCODENAME = "Mozilla";
+const CONST_PRODUCT     = "Gecko";
+const CONST_PRODUCTSUB  = "20100101";
+const CONST_VENDOR      = "";
+const CONST_VENDORSUB   = "";
+
+async function testNavigator() {
+  // Open a tab to collect result.
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser, TEST_PATH + "file_navigator.html");
+
+  let result = await ContentTask.spawn(tab.linkedBrowser, null, function() {
+    return content.document.getElementById("result").innerHTML;
+  });
+
+  result = JSON.parse(result);
+
+  is(result.appName, SPOOFED_APPNAME, "Navigator.appName is correctly spoofed.");
+  is(result.appVersion, SPOOFED_APPVERSION, "Navigator.appVersion is correctly spoofed.");
+  is(result.platform, SPOOFED_PLATFORM, "Navigator.platform is correctly spoofed.");
+  is(result.userAgent, spoofedUserAgent, "Navigator.userAgent is correctly spoofed.");
+  is(result.mimeTypesLength, 0, "Navigator.mimeTypes has a length of 0.");
+  is(result.pluginsLength, 0, "Navigator.plugins has a length of 0.");
+  is(result.oscpu, SPOOFED_OSCPU, "Navigator.oscpu is correctly spoofed.");
+  is(result.buildID, SPOOFED_BUILDID, "Navigator.buildID is correctly spoofed.");
+  is(result.hardwareConcurrency, SPOOFED_HW_CONCURRENCY, "Navigator.hardwareConcurrency is correctly spoofed.")
+
+  is(result.appCodeName, CONST_APPCODENAME, "Navigator.appCodeName reports correct constant value.");
+  is(result.product, CONST_PRODUCT, "Navigator.product reports correct constant value.");
+  is(result.productSub, CONST_PRODUCTSUB, "Navigator.productSub reports correct constant value.");
+  is(result.vendor, CONST_VENDOR, "Navigator.vendor reports correct constant value.");
+  is(result.vendorSub, CONST_VENDORSUB, "Navigator.vendorSub reports correct constant value.");
+
+  await BrowserTestUtils.removeTab(tab);
+}
+
+async function testWorkerNavigator() {
+  // Open a tab to collect result from worker.
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser, TEST_PATH + "file_dummy.html");
+
+  let result = await ContentTask.spawn(tab.linkedBrowser, null, async function() {
+    let worker = new content.SharedWorker("file_navigatorWorker.js", "WorkerNavigatorTest");
+
+    let res = await new Promise(resolve => {
+      worker.port.onmessage = function(e) {
+        resolve(e.data);
+      };
+    });
+
+    return res;
+  });
+
+  result = JSON.parse(result);
+
+  is(result.appName, SPOOFED_APPNAME, "Navigator.appName is correctly spoofed.");
+  is(result.appVersion, SPOOFED_APPVERSION, "Navigator.appVersion is correctly spoofed.");
+  is(result.platform, SPOOFED_PLATFORM, "Navigator.platform is correctly spoofed.");
+  is(result.userAgent, spoofedUserAgent, "Navigator.userAgent is correctly spoofed.");
+  is(result.hardwareConcurrency, SPOOFED_HW_CONCURRENCY, "Navigator.hardwareConcurrency is correctly spoofed.")
+
+  is(result.appCodeName, CONST_APPCODENAME, "Navigator.appCodeName reports correct constant value.");
+  is(result.product, CONST_PRODUCT, "Navigator.product reports correct constant value.");
+
+  await BrowserTestUtils.removeTab(tab);
+}
+
+add_task(async function setup() {
+  await SpecialPowers.pushPrefEnv({"set":
+    [["privacy.resistFingerprinting", true]]
+  });
+
+  let appInfo = Cc["@mozilla.org/xre/app-info;1"].getService(Ci.nsIXULAppInfo);
+  let appVersion = parseInt(appInfo.version);
+  let spoofedVersion = appVersion - (appVersion % 10);
+  spoofedUserAgent = `Mozilla/5.0 (Windows NT 6.1; rv:${spoofedVersion}.0) Gecko/20100101 Firefox/${spoofedVersion}.0`;
+});
+
+add_task(async function runNavigatorTest() {
+  await testNavigator();
+});
+
+add_task(async function runWorkerNavigatorTest() {
+  await testWorkerNavigator();
+});
+
+// This tests that 'general.*.override' should not override spoofed values.
+add_task(async function runOverrideTest() {
+  await SpecialPowers.pushPrefEnv({"set":
+    [
+      ["general.appname.override", "appName overridden"],
+      ["general.appversion.override", "appVersion overridden"],
+      ["general.platform.override", "platform overridden"],
+      ["general.useragent.override", "userAgent overridden"],
+      ["general.oscpu.override", "oscpu overridden"],
+      ["general.buildID.override", "buildID overridden"],
+    ]
+  });
+
+  await testNavigator();
+
+  await testWorkerNavigator();
+});
diff --git a/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_newWindow.js b/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_newWindow.js
index 8a278ec95260..3e572d10ee73 100644
--- a/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_newWindow.js
+++ b/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_newWindow.js
@@ -6,7 +6,7 @@
 const { classes: Cc, Constructor: CC, interfaces: Ci, utils: Cu } = Components;
 
 const TEST_DOMAIN = "http://example.net/";
-const TEST_PATH = TEST_DOMAIN + "browser/browser/components/resistFingerprinting/test/browser/";
+const TEST_PATH = TEST_DOMAIN + "browser/browser/components/resistfingerprinting/test/browser/";
 
 let gMaxAvailWidth;
 let gMaxAvailHeight;
diff --git a/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_open_max.js b/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_open_max.js
index a1738fe67b1a..2cf9f5a4c1fb 100644
--- a/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_open_max.js
+++ b/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_open_max.js
@@ -7,7 +7,7 @@
 const { classes: Cc, Constructor: CC, interfaces: Ci, utils: Cu } = Components;
 
 const TEST_DOMAIN = "http://example.net/";
-const TEST_PATH = TEST_DOMAIN + "browser/browser/components/resistFingerprinting/test/browser/";
+const TEST_PATH = TEST_DOMAIN + "browser/browser/components/resistfingerprinting/test/browser/";
 
 let gMaxAvailWidth;
 let gMaxAvailHeight;
diff --git a/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_open_mid.js b/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_open_mid.js
index e623e49242fe..fea81803d361 100644
--- a/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_open_mid.js
+++ b/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_open_mid.js
@@ -7,7 +7,7 @@
 const { classes: Cc, Constructor: CC, interfaces: Ci, utils: Cu } = Components;
 
 const TEST_DOMAIN = "http://example.net/";
-const TEST_PATH = TEST_DOMAIN + "browser/browser/components/resistFingerprinting/test/browser/";
+const TEST_PATH = TEST_DOMAIN + "browser/browser/components/resistfingerprinting/test/browser/";
 
 let gMaxAvailWidth;
 let gMaxAvailHeight;
diff --git a/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_open_min.js b/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_open_min.js
index 3dcdd30a8ebd..50b655c42e30 100644
--- a/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_open_min.js
+++ b/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_open_min.js
@@ -7,7 +7,7 @@
 const { classes: Cc, Constructor: CC, interfaces: Ci, utils: Cu } = Components;
 
 const TEST_DOMAIN = "http://example.net/";
-const TEST_PATH = TEST_DOMAIN + "browser/browser/components/resistFingerprinting/test/browser/";
+const TEST_PATH = TEST_DOMAIN + "browser/browser/components/resistfingerprinting/test/browser/";
 
 let gMaxAvailWidth;
 let gMaxAvailHeight;
diff --git a/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_windowSetting_max.js b/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_windowSetting_max.js
index c06dc568f8b9..112df4eeb872 100644
--- a/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_windowSetting_max.js
+++ b/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_windowSetting_max.js
@@ -7,7 +7,7 @@
 const { classes: Cc, Constructor: CC, interfaces: Ci, utils: Cu } = Components;
 
 const TEST_DOMAIN = "http://example.net/";
-const TEST_PATH = TEST_DOMAIN + "browser/browser/components/resistFingerprinting/test/browser/";
+const TEST_PATH = TEST_DOMAIN + "browser/browser/components/resistfingerprinting/test/browser/";
 
 let gMaxAvailWidth;
 let gMaxAvailHeight;
diff --git a/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_windowSetting_mid.js b/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_windowSetting_mid.js
index c3deb1500bfd..a406a2411ce0 100644
--- a/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_windowSetting_mid.js
+++ b/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_windowSetting_mid.js
@@ -7,7 +7,7 @@
 const { classes: Cc, Constructor: CC, interfaces: Ci, utils: Cu } = Components;
 
 const TEST_DOMAIN = "http://example.net/";
-const TEST_PATH = TEST_DOMAIN + "browser/browser/components/resistFingerprinting/test/browser/";
+const TEST_PATH = TEST_DOMAIN + "browser/browser/components/resistfingerprinting/test/browser/";
 
 let gMaxAvailWidth;
 let gMaxAvailHeight;
diff --git a/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_windowSetting_min.js b/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_windowSetting_min.js
index 098c32c1df55..a18a52a2b9f0 100644
--- a/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_windowSetting_min.js
+++ b/browser/components/resistfingerprinting/test/browser/browser_roundedWindow_windowSetting_min.js
@@ -7,7 +7,7 @@
 const { classes: Cc, Constructor: CC, interfaces: Ci, utils: Cu } = Components;
 
 const TEST_DOMAIN = "http://example.net/";
-const TEST_PATH = TEST_DOMAIN + "browser/browser/components/resistFingerprinting/test/browser/";
+const TEST_PATH = TEST_DOMAIN + "browser/browser/components/resistfingerprinting/test/browser/";
 
 let gMaxAvailWidth;
 let gMaxAvailHeight;
diff --git a/browser/components/resistfingerprinting/test/browser/browser_timezone.js b/browser/components/resistfingerprinting/test/browser/browser_timezone.js
index 966b3589f916..c75778ddd9d3 100644
--- a/browser/components/resistfingerprinting/test/browser/browser_timezone.js
+++ b/browser/components/resistfingerprinting/test/browser/browser_timezone.js
@@ -4,7 +4,7 @@
  */
 
 const TEST_DOMAIN = "http://example.net/";
-const TEST_PATH = TEST_DOMAIN + "browser/browser/components/resistFingerprinting/test/browser/";
+const TEST_PATH = TEST_DOMAIN + "browser/browser/components/resistfingerprinting/test/browser/";
 
 add_task(async function setup() {
   await SpecialPowers.pushPrefEnv({"set":
diff --git a/browser/components/resistfingerprinting/test/browser/file_navigator.html b/browser/components/resistfingerprinting/test/browser/file_navigator.html
new file mode 100644
index 000000000000..6c9b1d18c9ba
--- /dev/null
+++ b/browser/components/resistfingerprinting/test/browser/file_navigator.html
@@ -0,0 +1,33 @@
+<html>
+<head>
+<title>Test page for navigator object</title>
+<meta http-equiv="Content-Type" content="text/html;charset=utf-8"></meta>
+<script>
+  // This page will collect information from the navigator object and store
+  // the result at a paragraph in the page.
+  function collect() {
+    let result = {};
+
+    result["appCodeName"] = navigator.appCodeName;
+    result["appName"] = navigator.appName;
+    result["appVersion"] = navigator.appVersion;
+    result["platform"] = navigator.platform;
+    result["userAgent"] = navigator.userAgent;
+    result["product"] = navigator.product;
+    result["productSub"] = navigator.productSub;
+    result["vendor"] = navigator.vendor;
+    result["vendorSub"] = navigator.vendorSub;
+    result["mimeTypesLength"] = navigator.mimeTypes.length;
+    result["pluginsLength"] = navigator.plugins.length;
+    result["oscpu"] = navigator.oscpu;
+    result["buildID"] = navigator.buildID;
+    result["hardwareConcurrency"] = navigator.hardwareConcurrency;
+
+    document.getElementById("result").innerHTML = JSON.stringify(result);
+  }
+</script>
+</head>
+<body onload="collect();">
+<p id="result"></p>
+</body>
+</html>
diff --git a/browser/components/resistfingerprinting/test/browser/file_navigatorWorker.js b/browser/components/resistfingerprinting/test/browser/file_navigatorWorker.js
new file mode 100644
index 000000000000..703e4afd9181
--- /dev/null
+++ b/browser/components/resistfingerprinting/test/browser/file_navigatorWorker.js
@@ -0,0 +1,19 @@
+/* eslint-env worker */
+
+onconnect = function(e) {
+  let port = e.ports[0];
+
+  let navigatorObj = self.navigator;
+  let result = {};
+
+  result["appCodeName"] = navigatorObj.appCodeName;
+  result["appName"] = navigatorObj.appName;
+  result["appVersion"] = navigatorObj.appVersion;
+  result["platform"] = navigatorObj.platform;
+  result["userAgent"] = navigatorObj.userAgent;
+  result["product"] = navigatorObj.product;
+  result["hardwareConcurrency"] = navigatorObj.hardwareConcurrency;
+
+  port.postMessage(JSON.stringify(result));
+  port.start();
+};
diff --git a/browser/components/resistfingerprinting/test/browser/head.js b/browser/components/resistfingerprinting/test/browser/head.js
index d8a5ed0fcf6b..5810966f25bf 100644
--- a/browser/components/resistfingerprinting/test/browser/head.js
+++ b/browser/components/resistfingerprinting/test/browser/head.js
@@ -11,7 +11,7 @@ async function calcMaximumAvailSize(aChromeWidth, aChromeHeight) {
   let chromeUIWidth;
   let chromeUIHeight;
   let testPath = "http://example.net/browser/browser/" +
-                 "components/resistFingerprinting/test/browser/"
+                 "components/resistfingerprinting/test/browser/"
 
   // If the chrome UI dimensions is not given, we will calculate it.
   if (!aChromeWidth || !aChromeHeight) {