--- a/dom/workers/test/serviceworkers/fetch/origin/origin_test.js
+++ b/dom/workers/test/serviceworkers/fetch/origin/origin_test.js
@@ -1,3 +1,23 @@
+var prefix = "/tests/dom/workers/test/serviceworkers/fetch/origin/";
+
+self.addEventListener("install", function(event) {
+  event.waitUntil(
+    self.caches.open("origin-cache")
+      .then(c => {
+        return c.add(prefix + 'index.sjs');
+      })
+  );
+});
+
 self.addEventListener("fetch", function(event) {
-  event.respondWith(fetch(event.request));
+  if (event.request.url.indexOf("index-cached.sjs") >= 0) {
+    event.respondWith(
+      self.caches.open("origin-cache")
+        .then(c => {
+          return c.match(prefix + 'index.sjs');
+        })
+    );
+  } else {
+    event.respondWith(fetch(event.request));
+  }
 });

new file mode 100644
--- /dev/null
+++ b/dom/workers/test/serviceworkers/fetch/origin/realindex.html^headers^
@@ -0,0 +1,1 @@
+Access-Control-Allow-Origin: http://mochi.test:8888

--- a/dom/workers/test/serviceworkers/mochitest.ini
+++ b/dom/workers/test/serviceworkers/mochitest.ini
@@ -44,16 +44,17 @@ support-files =
   fetch/https/unregister.html
   fetch/https/https_test.js
   fetch/https/clonedresponse/index.html
   fetch/https/clonedresponse/register.html
   fetch/https/clonedresponse/unregister.html
   fetch/https/clonedresponse/https_test.js
   fetch/origin/index.sjs
   fetch/origin/realindex.html
+  fetch/origin/realindex.html^headers^
   fetch/origin/register.html
   fetch/origin/unregister.html
   fetch/origin/origin_test.js
   fetch/requesturl/index.html
   fetch/requesturl/redirect.sjs
   fetch/requesturl/redirector.html
   fetch/requesturl/register.html
   fetch/requesturl/requesturl_test.js
@@ -160,8 +161,9 @@ support-files =
 [test_service_worker_allowed.html]
 [test_app_protocol.html]
 [test_claim_fetch.html]
 [test_force_refresh.html]
 [test_skip_waiting.html]
 [test_strict_mode_error.html]
 [test_cross_origin_url_after_redirect.html]
 [test_origin_after_redirect.html]
+[test_origin_after_redirect_cached.html]

--- a/dom/workers/test/serviceworkers/test_origin_after_redirect.html
+++ b/dom/workers/test/serviceworkers/test_origin_after_redirect.html
@@ -43,14 +43,15 @@
   }
 
   SimpleTest.waitForExplicitFinish();
   onload = function() {
     SpecialPowers.pushPrefEnv({"set": [
       ["dom.serviceWorkers.exemptFromPerDomainMax", true],
       ["dom.serviceWorkers.enabled", true],
       ["dom.serviceWorkers.testing.enabled", true],
+      ["dom.caches.enabled", true],
     ]}, runTest);
   };
 </script>
 </pre>
 </body>
 </html>

copy from dom/workers/test/serviceworkers/test_origin_after_redirect.html
copy to dom/workers/test/serviceworkers/test_origin_after_redirect_cached.html
--- a/dom/workers/test/serviceworkers/test_origin_after_redirect.html
+++ b/dom/workers/test/serviceworkers/test_origin_after_redirect_cached.html
@@ -21,17 +21,17 @@
   function runTest() {
     iframe = document.querySelector("iframe");
     iframe.src = "/tests/dom/workers/test/serviceworkers/fetch/origin/register.html";
     var win;
     window.onmessage = function(e) {
       if (e.data.status == "ok") {
         ok(e.data.result, e.data.message);
       } else if (e.data.status == "registrationdone") {
-        win = window.open("/tests/dom/workers/test/serviceworkers/fetch/origin/index.sjs", "mywindow", "width=100,height=100");
+        win = window.open("/tests/dom/workers/test/serviceworkers/fetch/origin/index-cached.sjs", "mywindow", "width=100,height=100");
       } else if (e.data.status == "domain") {
         is(e.data.data, "example.org", "Correct domain expected");
       } else if (e.data.status == "origin") {
         is(e.data.data, "http://example.org", "Correct origin expected");
       } else if (e.data.status == "done") {
         win.close();
         iframe.src = "/tests/dom/workers/test/serviceworkers/fetch/origin/unregister.html";
       } else if (e.data.status == "unregistrationdone") {
@@ -43,14 +43,15 @@
   }
 
   SimpleTest.waitForExplicitFinish();
   onload = function() {
     SpecialPowers.pushPrefEnv({"set": [
       ["dom.serviceWorkers.exemptFromPerDomainMax", true],
       ["dom.serviceWorkers.enabled", true],
       ["dom.serviceWorkers.testing.enabled", true],
+      ["dom.caches.enabled", true],
     ]}, runTest);
   };
 </script>
 </pre>
 </body>
 </html>