--- a/dom/tests/mochitest/fetch/test_fetch_cors.js
+++ b/dom/tests/mochitest/fetch/test_fetch_cors.js
@@ -59,19 +59,19 @@ function testSameOriginCredentials() {
   var tests = [
               {
                 // Initialize by setting a cookie.
                 pass: 1,
                 setCookie: cookieStr,
                 withCred: "same-origin",
               },
               {
-                // Default mode is "omit".
+                // Default mode is "same-origin".
                 pass: 1,
-                noCookie: 1,
+                cookie: cookieStr,
               },
               {
                 pass: 1,
                 noCookie: 1,
                 withCred: "omit",
               },
               {
                 pass: 1,

--- a/dom/tests/mochitest/fetch/test_request.js
+++ b/dom/tests/mochitest/fetch/test_request.js
@@ -1,27 +1,27 @@
 function testDefaultCtor() {
   var req = new Request("");
   is(req.method, "GET", "Default Request method is GET");
   ok(req.headers instanceof Headers, "Request should have non-null Headers object");
   is(req.url, self.location.href, "URL should be resolved with entry settings object's API base URL");
   is(req.destination, "", "Default destination is the empty string.");
   is(req.referrer, "about:client", "Default referrer is `client` which serializes to about:client.");
   is(req.mode, "cors", "Request mode for string input is cors");
-  is(req.credentials, "omit", "Default Request credentials is omit");
+  is(req.credentials, "same-origin", "Default Request credentials is same-origin");
   is(req.cache, "default", "Default Request cache is default");
 
   var req = new Request(req);
   is(req.method, "GET", "Default Request method is GET");
   ok(req.headers instanceof Headers, "Request should have non-null Headers object");
   is(req.url, self.location.href, "URL should be resolved with entry settings object's API base URL");
   is(req.destination, "", "Default destination is the empty string.");
   is(req.referrer, "about:client", "Default referrer is `client` which serializes to about:client.");
   is(req.mode, "cors", "Request mode string input is cors");
-  is(req.credentials, "omit", "Default Request credentials is omit");
+  is(req.credentials, "same-origin", "Default Request credentials is same-origin");
   is(req.cache, "default", "Default Request cache is default");
 }
 
 function testClone() {
   var orig = new Request("./cloned_request.txt", {
               method: 'POST',
               headers: { "Sample-Header": "5" },
               body: "Sample body",