--- a/services/common/tests/unit/test_kinto_updater.js
+++ b/services/common/tests/unit/test_kinto_updater.js
@@ -56,17 +56,17 @@ add_task(function* test_check_maybeSync(
   let startTime = Date.now();
 
   let updater = Cu.import("resource://services-common/kinto-updater.js");
 
   let syncPromise = new Promise(function(resolve, reject) {
     // add a test kinto client that will respond to lastModified information
     // for a collection called 'test-collection'
     updater.addTestKintoClient("test-collection", {
-      maybeSync: function(lastModified, serverTime) {
+      maybeSync: (lastModified, serverTime) => {
         do_check_eq(lastModified, 1000);
         do_check_eq(serverTime, 2000);
         resolve();
       }
     });
     updater.checkVersions();
   });
 
@@ -155,17 +155,15 @@ function getSampleResponse(req, port) {
         "last_modified": 1000,
         "bucket": "blocklists",
         "id": "254cbb9e-6888-4d9f-8e60-58b74faa8778",
         "collection": "test-collection"
       }]})
     }
   };
 
-  // if (req.headers.get("If-None-Match") == '"1100"')
-  // "TypeError: req.headers.get is not a function"
-  // https://developer.mozilla.org/en-US/docs/Web/API/Request/headers
-  if (req._headers._headers["if-none-match"] && req._headers._headers["if-none-match"][0] == "\"1100\"")
+  if (req.getHeader("if-none-match") == "\"1100\"") {
     return {sampleHeaders: [], status: {status: 304, statusText: "Not Modified"}, responseBody: ""};
+  }
 
   return responses[`${req.method}:${req.path}?${req.queryString}`] ||
          responses[req.method];
 }