Merging upstream version 125.0.1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

52 files changed, 194 insertions, 208 deletions

diff --git a/services/sync/Weave.sys.mjs b/services/sync/Weave.sys.mjs
index 05a7031a73..1c4bb44928 100644
--- a/services/sync/Weave.sys.mjs
+++ b/services/sync/Weave.sys.mjs
@@ -156,7 +156,7 @@ AboutWeaveLog.prototype = {
     "nsISupportsWeakReference",
   ]),
 
-  getURIFlags(aURI) {
+  getURIFlags() {
     return 0;
   },
 
diff --git a/services/sync/docs/engines.rst b/services/sync/docs/engines.rst
index 7a4fa721af..a9a60d4e79 100644
--- a/services/sync/docs/engines.rst
+++ b/services/sync/docs/engines.rst
@@ -80,7 +80,7 @@ are open on other devices. There's no database - if we haven't synced yet we
 don't know what other tabs are open, and when we do know, the list is just
 stored in memory.
 
-The `SyncedTabs module <https://searchfox.org/mozilla-central/source/services/sync/modules/SyncedTabs.jsm>`_
+The `SyncedTabs module <https://searchfox.org/mozilla-central/source/services/sync/modules/SyncedTabs.sys.mjs>`_
 is the main interface the browser uses to get the list of tabs from other
 devices.
 
@@ -111,7 +111,7 @@ treat them as a single engine in practice.
 
 As a result, only a shim is in the `services/sync/modules/engines/` directory,
 while the actual logic is
-`next to the storage implementation <https://searchfox.org/mozilla-central/source/toolkit/components/formautofill/FormAutofillSync.jsm>`_.
+`next to the storage implementation <https://searchfox.org/mozilla-central/source/toolkit/components/formautofill/FormAutofillSync.sys.mjs>`_.
 
 This engine has a unique twist on the "mirror" concept described above -
 whenever a change is made to a fields, the original value of the field is
diff --git a/services/sync/modules-testing/fakeservices.sys.mjs b/services/sync/modules-testing/fakeservices.sys.mjs
index 4fd7534bf1..bf2d143203 100644
--- a/services/sync/modules-testing/fakeservices.sys.mjs
+++ b/services/sync/modules-testing/fakeservices.sys.mjs
@@ -29,7 +29,7 @@ export function FakeFilesystemService(contents) {
     self.fakeContents["weave/" + filePath + ".json"] = JSON.stringify(json);
   };
 
-  Utils.jsonLoad = async function jsonLoad(filePath, that) {
+  Utils.jsonLoad = async function jsonLoad(filePath) {
     let obj;
     let json = self.fakeContents["weave/" + filePath + ".json"];
     if (json) {
@@ -38,14 +38,14 @@ export function FakeFilesystemService(contents) {
     return obj;
   };
 
-  Utils.jsonMove = function jsonMove(aFrom, aTo, that) {
+  Utils.jsonMove = function jsonMove(aFrom, aTo) {
     const fromPath = "weave/" + aFrom + ".json";
     self.fakeContents["weave/" + aTo + ".json"] = self.fakeContents[fromPath];
     delete self.fakeContents[fromPath];
     return Promise.resolve();
   };
 
-  Utils.jsonRemove = function jsonRemove(filePath, that) {
+  Utils.jsonRemove = function jsonRemove(filePath) {
     delete self.fakeContents["weave/" + filePath + ".json"];
     return Promise.resolve();
   };
@@ -79,19 +79,17 @@ export function FakeCryptoService() {
   delete Weave.Crypto; // get rid of the getter first
   Weave.Crypto = this;
 
-  RawCryptoWrapper.prototype.ciphertextHMAC = function ciphertextHMAC(
-    keyBundle
-  ) {
+  RawCryptoWrapper.prototype.ciphertextHMAC = function ciphertextHMAC() {
     return fakeSHA256HMAC(this.ciphertext);
   };
 }
 
 FakeCryptoService.prototype = {
-  async encrypt(clearText, symmetricKey, iv) {
+  async encrypt(clearText) {
     return clearText;
   },
 
-  async decrypt(cipherText, symmetricKey, iv) {
+  async decrypt(cipherText) {
     return cipherText;
   },
 
@@ -104,7 +102,7 @@ FakeCryptoService.prototype = {
     return btoa("fake-fake-fake-random-iv");
   },
 
-  expandData: function expandData(data, len) {
+  expandData: function expandData(data) {
     return data;
   },
 
diff --git a/services/sync/modules-testing/fxa_utils.sys.mjs b/services/sync/modules-testing/fxa_utils.sys.mjs
index c953f0eaa3..fdb9e261c9 100644
--- a/services/sync/modules-testing/fxa_utils.sys.mjs
+++ b/services/sync/modules-testing/fxa_utils.sys.mjs
@@ -23,7 +23,7 @@ export var initializeIdentityWithTokenServerResponse = function (response) {
   }
 
   // A mock request object.
-  function MockRESTRequest(url) {}
+  function MockRESTRequest() {}
   MockRESTRequest.prototype = {
     _log: requestLog,
     setHeader() {},
diff --git a/services/sync/modules/UIState.sys.mjs b/services/sync/modules/UIState.sys.mjs
index 8981d81f7d..6a45130cb1 100644
--- a/services/sync/modules/UIState.sys.mjs
+++ b/services/sync/modules/UIState.sys.mjs
@@ -87,7 +87,7 @@ const UIStateInternal = {
     this._initialized = false;
   },
 
-  observe(subject, topic, data) {
+  observe(subject, topic) {
     switch (topic) {
       case "weave:service:sync:start":
         this.toggleSyncActivity(true);
diff --git a/services/sync/modules/bridged_engine.sys.mjs b/services/sync/modules/bridged_engine.sys.mjs
index 45e5f685cd..3e40a80505 100644
--- a/services/sync/modules/bridged_engine.sys.mjs
+++ b/services/sync/modules/bridged_engine.sys.mjs
@@ -43,7 +43,7 @@ class BridgedStore {
     this._batchChunkSize = 500;
   }
 
-  async applyIncomingBatch(records, countTelemetry) {
+  async applyIncomingBatch(records) {
     for (let chunk of lazy.PlacesUtils.chunkArray(
       records,
       this._batchChunkSize
@@ -145,7 +145,7 @@ class InterruptedError extends Error {
 
 /**
  * Adapts a `Log.sys.mjs` logger to a `mozIServicesLogSink`. This class is copied
- * from `SyncedBookmarksMirror.jsm`.
+ * from `SyncedBookmarksMirror.sys.mjs`.
  */
 export class LogAdapter {
   constructor(log) {
diff --git a/services/sync/modules/collection_validator.sys.mjs b/services/sync/modules/collection_validator.sys.mjs
index a64ede10e9..1f40110ca9 100644
--- a/services/sync/modules/collection_validator.sys.mjs
+++ b/services/sync/modules/collection_validator.sys.mjs
@@ -114,13 +114,13 @@ export class CollectionValidator {
 
   // Return whether or not a server item should be present on the client. Expected
   // to be overridden.
-  clientUnderstands(item) {
+  clientUnderstands() {
     return true;
   }
 
   // Return whether or not a client item should be present on the server. Expected
   // to be overridden
-  async syncedByClient(item) {
+  async syncedByClient() {
     return true;
   }
 
diff --git a/services/sync/modules/constants.sys.mjs b/services/sync/modules/constants.sys.mjs
index 35c0ac2f0b..958e3345e6 100644
--- a/services/sync/modules/constants.sys.mjs
+++ b/services/sync/modules/constants.sys.mjs
@@ -4,7 +4,7 @@
 
 // Don't manually modify this line, as it is automatically replaced on merge day
 // by the gecko_migration.py script.
-export const WEAVE_VERSION = "1.126.0";
+export const WEAVE_VERSION = "1.127.0";
 
 // Sync Server API version that the client supports.
 export const SYNC_API_VERSION = "1.5";
diff --git a/services/sync/modules/engines.sys.mjs b/services/sync/modules/engines.sys.mjs
index 0d490ac4b3..63b4c02cc5 100644
--- a/services/sync/modules/engines.sys.mjs
+++ b/services/sync/modules/engines.sys.mjs
@@ -113,12 +113,12 @@ Tracker.prototype = {
   },
 
   // Also unsupported.
-  async addChangedID(id, when) {
+  async addChangedID() {
     throw new TypeError("Can't add changed ID to this tracker");
   },
 
   // Ditto.
-  async removeChangedID(...ids) {
+  async removeChangedID() {
     throw new TypeError("Can't remove changed IDs from this tracker");
   },
 
@@ -155,7 +155,7 @@ Tracker.prototype = {
   // Override these in your subclasses.
   onStart() {},
   onStop() {},
-  async observe(subject, topic, data) {},
+  async observe() {},
 
   engineIsEnabled() {
     if (!this.engine) {
@@ -437,7 +437,7 @@ Store.prototype = {
    * @param record
    *        The store record to create an item from
    */
-  async create(record) {
+  async create() {
     throw new Error("override create in a subclass");
   },
 
@@ -450,7 +450,7 @@ Store.prototype = {
    * @param record
    *        The store record to delete an item from
    */
-  async remove(record) {
+  async remove() {
     throw new Error("override remove in a subclass");
   },
 
@@ -463,7 +463,7 @@ Store.prototype = {
    * @param record
    *        The record to use to update an item from
    */
-  async update(record) {
+  async update() {
     throw new Error("override update in a subclass");
   },
 
@@ -477,7 +477,7 @@ Store.prototype = {
    *         string record ID
    * @return boolean indicating whether record exists locally
    */
-  async itemExists(id) {
+  async itemExists() {
     throw new Error("override itemExists in a subclass");
   },
 
@@ -495,7 +495,7 @@ Store.prototype = {
    *         constructor for the newly-created record.
    * @return record type for this engine
    */
-  async createRecord(id, collection) {
+  async createRecord() {
     throw new Error("override createRecord in a subclass");
   },
 
@@ -507,7 +507,7 @@ Store.prototype = {
    * @param  newID
    *         string new record ID
    */
-  async changeItemID(oldID, newID) {
+  async changeItemID() {
     throw new Error("override changeItemID in a subclass");
   },
 
@@ -1040,7 +1040,7 @@ SyncEngine.prototype = {
    * Note: Overriding engines must take resyncs into account -- score will not
    * be cleared.
    */
-  shouldSkipSync(syncReason) {
+  shouldSkipSync() {
     return false;
   },
 
@@ -1550,7 +1550,7 @@ SyncEngine.prototype = {
   // Indicates whether an incoming item should be deleted from the server at
   // the end of the sync. Engines can override this method to clean up records
   // that shouldn't be on the server.
-  _shouldDeleteRemotely(remoteItem) {
+  _shouldDeleteRemotely() {
     return false;
   },
 
@@ -1560,7 +1560,7 @@ SyncEngine.prototype = {
    *
    * @return GUID of the similar item; falsy otherwise
    */
-  async _findDupe(item) {
+  async _findDupe() {
     // By default, assume there's no dupe items for the engine
   },
 
@@ -1568,7 +1568,7 @@ SyncEngine.prototype = {
    * Called before a remote record is discarded due to failed reconciliation.
    * Used by bookmark sync to merge folder child orders.
    */
-  beforeRecordDiscard(localRecord, remoteRecord, remoteIsNewer) {},
+  beforeRecordDiscard() {},
 
   // Called when the server has a record marked as deleted, but locally we've
   // changed it more recently than the deletion. If we return false, the
@@ -1576,7 +1576,7 @@ SyncEngine.prototype = {
   // record to the server -- any extra work that's needed as part of this
   // process should be done at this point (such as mark the record's parent
   // for reuploading in the case of bookmarks).
-  async _shouldReviveRemotelyDeletedRecord(remoteItem) {
+  async _shouldReviveRemotelyDeletedRecord() {
     return true;
   },
 
@@ -1948,7 +1948,7 @@ SyncEngine.prototype = {
     }
   },
 
-  async _onRecordsWritten(succeeded, failed, serverModifiedTime) {
+  async _onRecordsWritten() {
     // Implement this method to take specific actions against successfully
     // uploaded records and failed records.
   },
diff --git a/services/sync/modules/engines/bookmarks.sys.mjs b/services/sync/modules/engines/bookmarks.sys.mjs
index 3c1396f67d..4995da6899 100644
--- a/services/sync/modules/engines/bookmarks.sys.mjs
+++ b/services/sync/modules/engines/bookmarks.sys.mjs
@@ -513,7 +513,7 @@ BookmarksEngine.prototype = {
     await this._apply();
   },
 
-  async _reconcile(item) {
+  async _reconcile() {
     return true;
   },
 
@@ -752,7 +752,7 @@ BookmarksStore.prototype = {
     });
   },
 
-  async applyIncomingBatch(records, countTelemetry) {
+  async applyIncomingBatch(records) {
     let buf = await this.ensureOpenMirror();
     for (let chunk of lazy.PlacesUtils.chunkArray(
       records,
@@ -921,11 +921,11 @@ Object.setPrototypeOf(BookmarksTracker.prototype, Tracker.prototype);
 class BookmarksChangeset extends Changeset {
   // Only `_reconcile` calls `getModifiedTimestamp` and `has`, and the engine
   // does its own reconciliation.
-  getModifiedTimestamp(id) {
+  getModifiedTimestamp() {
     throw new Error("Don't use timestamps to resolve bookmark conflicts");
   }
 
-  has(id) {
+  has() {
     throw new Error("Don't use the changeset to resolve bookmark conflicts");
   }
 
diff --git a/services/sync/modules/engines/clients.sys.mjs b/services/sync/modules/engines/clients.sys.mjs
index eda92bd75b..cb391982e0 100644
--- a/services/sync/modules/engines/clients.sys.mjs
+++ b/services/sync/modules/engines/clients.sys.mjs
@@ -1107,7 +1107,7 @@ ClientsTracker.prototype = {
     Svc.Obs.remove("fxaccounts:new_device_id", this.asyncObserver);
   },
 
-  async observe(subject, topic, data) {
+  async observe(subject, topic) {
     switch (topic) {
       case "nsPref:changed":
         this._log.debug("client.name preference changed");
diff --git a/services/sync/modules/engines/extension-storage.sys.mjs b/services/sync/modules/engines/extension-storage.sys.mjs
index d2671978c8..693d94f647 100644
--- a/services/sync/modules/engines/extension-storage.sys.mjs
+++ b/services/sync/modules/engines/extension-storage.sys.mjs
@@ -124,7 +124,7 @@ ExtensionStorageEngineBridge.prototype = {
   },
 
   _takeMigrationInfo() {
-    return new Promise((resolve, reject) => {
+    return new Promise(resolve => {
       this.component
         .QueryInterface(Ci.mozIExtensionStorageArea)
         .takeMigrationInfo({
@@ -291,7 +291,7 @@ ExtensionStorageTracker.prototype = {
     lazy.Svc.Obs.remove("ext.storage.sync-changed", this.asyncObserver);
   },
 
-  async observe(subject, topic, data) {
+  async observe(subject, topic) {
     if (this.ignoreAll) {
       return;
     }
diff --git a/services/sync/modules/engines/forms.sys.mjs b/services/sync/modules/engines/forms.sys.mjs
index 3516327659..0d63eb96d1 100644
--- a/services/sync/modules/engines/forms.sys.mjs
+++ b/services/sync/modules/engines/forms.sys.mjs
@@ -189,7 +189,7 @@ FormStore.prototype = {
     await this._processChange(change);
   },
 
-  async update(record) {
+  async update() {
     this._log.trace("Ignoring form record update request!");
   },
 
diff --git a/services/sync/modules/engines/prefs.sys.mjs b/services/sync/modules/engines/prefs.sys.mjs
index f29a9e7b59..cb494ec70e 100644
--- a/services/sync/modules/engines/prefs.sys.mjs
+++ b/services/sync/modules/engines/prefs.sys.mjs
@@ -386,7 +386,7 @@ PrefStore.prototype = {
     return allprefs;
   },
 
-  async changeItemID(oldID, newID) {
+  async changeItemID() {
     this._log.trace("PrefStore GUID is constant!");
   },
 
@@ -406,11 +406,11 @@ PrefStore.prototype = {
     return record;
   },
 
-  async create(record) {
+  async create() {
     this._log.trace("Ignoring create request");
   },
 
-  async remove(record) {
+  async remove() {
     this._log.trace("Ignoring remove request");
   },
 
diff --git a/services/sync/modules/engines/tabs.sys.mjs b/services/sync/modules/engines/tabs.sys.mjs
index 861e051d1a..93747665f2 100644
--- a/services/sync/modules/engines/tabs.sys.mjs
+++ b/services/sync/modules/engines/tabs.sys.mjs
@@ -430,7 +430,7 @@ export const TabProvider = {
         .then(iconData => {
           thisTab.icon = iconData.uri.spec;
         })
-        .catch(ex => {
+        .catch(() => {
           log.trace(
             `Failed to fetch favicon for ${url}`,
             thisTab.urlHistory[0]
@@ -503,7 +503,7 @@ TabTracker.prototype = {
     }
   },
 
-  async observe(subject, topic, data) {
+  async observe(subject, topic) {
     switch (topic) {
       case "domwindowopened":
         let onLoad = () => {
diff --git a/services/sync/modules/record.sys.mjs b/services/sync/modules/record.sys.mjs
index 7d5918a8ca..f8580cfbd4 100644
--- a/services/sync/modules/record.sys.mjs
+++ b/services/sync/modules/record.sys.mjs
@@ -182,7 +182,7 @@ RawCryptoWrapper.prototype = {
    * @param   {Cleartext} outgoingCleartext The cleartext to upload.
    * @returns {String}                      The serialized cleartext.
    */
-  transformBeforeEncrypt(outgoingCleartext) {
+  transformBeforeEncrypt() {
     throw new TypeError("Override to stringify outgoing records");
   },
 
@@ -194,7 +194,7 @@ RawCryptoWrapper.prototype = {
    * @param   {String} incomingCleartext The decrypted cleartext string.
    * @returns {Cleartext}                The parsed cleartext.
    */
-  transformAfterDecrypt(incomingCleartext) {
+  transformAfterDecrypt() {
     throw new TypeError("Override to parse incoming records");
   },
 
@@ -527,7 +527,7 @@ CollectionKeyManager.prototype = {
   /**
    * Create a WBO for the current keys.
    */
-  asWBO(collection, id) {
+  asWBO() {
     return this._makeWBO(this._collections, this._default);
   },
 
diff --git a/services/sync/modules/sync_auth.sys.mjs b/services/sync/modules/sync_auth.sys.mjs
index 6b8da4061c..cfa76827d5 100644
--- a/services/sync/modules/sync_auth.sys.mjs
+++ b/services/sync/modules/sync_auth.sys.mjs
@@ -164,7 +164,7 @@ SyncAuthManager.prototype = {
     this._token = null;
   },
 
-  async observe(subject, topic, data) {
+  async observe(subject, topic) {
     this._log.debug("observed " + topic);
     if (!this.username) {
       this._log.info("Sync is not configured, so ignoring the notification");
@@ -276,7 +276,7 @@ SyncAuthManager.prototype = {
    * allows us to avoid a network request for when we actually need the
    * migration info.
    */
-  prefetchMigrationSentinel(service) {
+  prefetchMigrationSentinel() {
     // nothing to do here until we decide to migrate away from FxA.
   },
 
@@ -387,22 +387,28 @@ SyncAuthManager.prototype = {
     // Do the token dance, with a retry in case of transient auth failure.
     // We need to prove that we know the sync key in order to get a token
     // from the tokenserver.
-    let getToken = async key => {
+    let getToken = async (key, accessToken) => {
       this._log.info("Getting a sync token from", this._tokenServerUrl);
-      let token = await this._fetchTokenUsingOAuth(key);
+      let token = await this._fetchTokenUsingOAuth(key, accessToken);
       this._log.trace("Successfully got a token");
       return token;
     };
 
+    const ttl = fxAccountsCommon.OAUTH_TOKEN_FOR_SYNC_LIFETIME_SECONDS;
     try {
       let token, key;
       try {
         this._log.info("Getting sync key");
-        key = await fxa.keys.getKeyForScope(SCOPE_OLD_SYNC);
+        const tokenAndKey = await fxa.getOAuthTokenAndKey({
+          scope: SCOPE_OLD_SYNC,
+          ttl,
+        });
+
+        key = tokenAndKey.key;
         if (!key) {
           throw new Error("browser does not have the sync key, cannot sync");
         }
-        token = await getToken(key);
+        token = await getToken(key, tokenAndKey.token);
       } catch (err) {
         // If we get a 401 fetching the token it may be that our auth tokens needed
         // to be regenerated; retry exactly once.
@@ -412,8 +418,11 @@ SyncAuthManager.prototype = {
         this._log.warn(
           "Token server returned 401, retrying token fetch with fresh credentials"
         );
-        key = await fxa.keys.getKeyForScope(SCOPE_OLD_SYNC);
-        token = await getToken(key);
+        const tokenAndKey = await fxa.getOAuthTokenAndKey({
+          scope: SCOPE_OLD_SYNC,
+          ttl,
+        });
+        token = await getToken(tokenAndKey.key, tokenAndKey.token);
       }
       // TODO: Make it be only 80% of the duration, so refresh the token
       // before it actually expires. This is to avoid sync storage errors
@@ -437,7 +446,7 @@ SyncAuthManager.prototype = {
         // A hawkclient error.
       } else if (err.code && err.code === 401) {
         err = new AuthenticationError(err, "hawkclient");
-        // An FxAccounts.jsm error.
+        // An FxAccounts.sys.mjs error.
       } else if (err.message == fxAccountsCommon.ERROR_AUTH_ERROR) {
         err = new AuthenticationError(err, "fxaccounts");
       }
@@ -460,17 +469,13 @@ SyncAuthManager.prototype = {
   },
 
   /**
-   * Generates an OAuth access_token using the OLD_SYNC scope and exchanges it
-   * for a TokenServer token.
-   *
+   * Exchanges an OAuth access_token for a TokenServer token.
    * @returns {Promise}
    * @private
    */
-  async _fetchTokenUsingOAuth(key) {
+  async _fetchTokenUsingOAuth(key, accessToken) {
     this._log.debug("Getting a token using OAuth");
     const fxa = this._fxaService;
-    const ttl = fxAccountsCommon.OAUTH_TOKEN_FOR_SYNC_LIFETIME_SECONDS;
-    const accessToken = await fxa.getOAuthToken({ scope: SCOPE_OLD_SYNC, ttl });
     const headers = {
       "X-KeyId": key.kid,
     };
diff --git a/services/sync/modules/telemetry.sys.mjs b/services/sync/modules/telemetry.sys.mjs
index c08f405b0e..28888ef277 100644
--- a/services/sync/modules/telemetry.sys.mjs
+++ b/services/sync/modules/telemetry.sys.mjs
@@ -241,10 +241,14 @@ export class ErrorSanitizer {
     NotAllowedError: this.E_PERMISSION_DENIED,
   };
 
+  // IOUtils error messages include the specific nsresult error code that caused them.
+  static NS_ERROR_RE = new RegExp(/ \(NS_ERROR_.*\)$/);
+
   static #cleanOSErrorMessage(message, error = undefined) {
     if (DOMException.isInstance(error)) {
       const sub = this.DOMErrorSubstitutions[error.name];
       message = message.replaceAll("\\", "/");
+      message = message.replace(this.NS_ERROR_RE, "");
       if (sub) {
         return `${sub} ${message}`;
       }
diff --git a/services/sync/tests/tps/.eslintrc.js b/services/sync/tests/tps/.eslintrc.js
index 182e87933b..63c8344934 100644
--- a/services/sync/tests/tps/.eslintrc.js
+++ b/services/sync/tests/tps/.eslintrc.js
@@ -2,7 +2,7 @@
 
 module.exports = {
   globals: {
-    // Injected into tests via tps.jsm
+    // Injected into tests via tps.sys.mjs
     Addons: false,
     Addresses: false,
     Bookmarks: false,
diff --git a/services/sync/tests/unit/head_helpers.js b/services/sync/tests/unit/head_helpers.js
index e79e55e57f..865117e5d2 100644
--- a/services/sync/tests/unit/head_helpers.js
+++ b/services/sync/tests/unit/head_helpers.js
@@ -530,8 +530,8 @@ async function sync_engine_and_validate_telem(
 
 // Returns a promise that resolves once the specified observer notification
 // has fired.
-function promiseOneObserver(topic, callback) {
-  return new Promise((resolve, reject) => {
+function promiseOneObserver(topic) {
+  return new Promise(resolve => {
     let observer = function (subject, data) {
       Svc.Obs.remove(topic, observer);
       resolve({ subject, data });
diff --git a/services/sync/tests/unit/head_http_server.js b/services/sync/tests/unit/head_http_server.js
index 84dbb33951..d8603465c1 100644
--- a/services/sync/tests/unit/head_http_server.js
+++ b/services/sync/tests/unit/head_http_server.js
@@ -687,8 +687,8 @@ function track_collections_helper() {
  * prototype, and override as appropriate.
  */
 var SyncServerCallback = {
-  onCollectionDeleted: function onCollectionDeleted(user, collection) {},
-  onItemDeleted: function onItemDeleted(user, collection, wboID) {},
+  onCollectionDeleted: function onCollectionDeleted() {},
+  onItemDeleted: function onItemDeleted() {},
 
   /**
    * Called at the top of every request.
@@ -699,7 +699,7 @@ var SyncServerCallback = {
    * must be taken to not screw with the response body or headers that may
    * conflict with normal operation of this server.
    */
-  onRequest: function onRequest(request, response) {},
+  onRequest: function onRequest() {},
 };
 
 /**
diff --git a/services/sync/tests/unit/test_addon_utils.js b/services/sync/tests/unit/test_addon_utils.js
index c039bee16c..e9e49fb9ea 100644
--- a/services/sync/tests/unit/test_addon_utils.js
+++ b/services/sync/tests/unit/test_addon_utils.js
@@ -119,7 +119,7 @@ add_task(async function test_source_uri_rewrite() {
 
   let installCalled = false;
   Object.getPrototypeOf(AddonUtils).installAddonFromSearchResult =
-    async function testInstallAddon(addon, metadata) {
+    async function testInstallAddon(addon) {
       Assert.equal(
         SERVER_ADDRESS + "/require.xpi?src=sync",
         addon.sourceURI.spec
diff --git a/services/sync/tests/unit/test_addons_validator.js b/services/sync/tests/unit/test_addons_validator.js
index 60f2f8bf43..91f3f7b31b 100644
--- a/services/sync/tests/unit/test_addons_validator.js
+++ b/services/sync/tests/unit/test_addons_validator.js
@@ -49,7 +49,7 @@ function getDummyServerAndClient() {
 add_task(async function test_valid() {
   let { server, client } = getDummyServerAndClient();
   let validator = new AddonValidator({
-    _findDupe(item) {
+    _findDupe() {
       return null;
     },
     isAddonSyncable(item) {
diff --git a/services/sync/tests/unit/test_bookmark_engine.js b/services/sync/tests/unit/test_bookmark_engine.js
index 6274a6b836..2f5ac9dcd3 100644
--- a/services/sync/tests/unit/test_bookmark_engine.js
+++ b/services/sync/tests/unit/test_bookmark_engine.js
@@ -940,7 +940,7 @@ add_bookmark_test(async function test_sync_dateAdded(engine) {
     // Make sure it's within 24 hours of the right timestamp... This is a little
     // dodgey but we only really care that it's basically accurate and has the
     // right day.
-    ok(Math.abs(Date.now() - record3.dateAdded) < 24 * 60 * 60 * 1000);
+    Assert.less(Math.abs(Date.now() - record3.dateAdded), 24 * 60 * 60 * 1000);
 
     let record4 = await store.createRecord(item4GUID);
     equal(
diff --git a/services/sync/tests/unit/test_bookmark_tracker.js b/services/sync/tests/unit/test_bookmark_tracker.js
index 9cfbb4de78..8c26232cd5 100644
--- a/services/sync/tests/unit/test_bookmark_tracker.js
+++ b/services/sync/tests/unit/test_bookmark_tracker.js
@@ -54,8 +54,16 @@ async function verifyTrackedItems(tracked) {
   let trackedIDs = new Set(Object.keys(changedIDs));
   for (let guid of tracked) {
     ok(guid in changedIDs, `${guid} should be tracked`);
-    ok(changedIDs[guid].modified > 0, `${guid} should have a modified time`);
-    ok(changedIDs[guid].counter >= -1, `${guid} should have a change counter`);
+    Assert.greater(
+      changedIDs[guid].modified,
+      0,
+      `${guid} should have a modified time`
+    );
+    Assert.greaterOrEqual(
+      changedIDs[guid].counter,
+      -1,
+      `${guid} should have a change counter`
+    );
     trackedIDs.delete(guid);
   }
   equal(
@@ -770,7 +778,7 @@ add_task(async function test_onFaviconChanged() {
         iconURI,
         true,
         PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
-        (uri, dataLen, data, mimeType) => {
+        () => {
           resolve();
         },
         Services.scriptSecurityManager.getSystemPrincipal()
diff --git a/services/sync/tests/unit/test_clients_engine.js b/services/sync/tests/unit/test_clients_engine.js
index d910a67503..9a5115db4e 100644
--- a/services/sync/tests/unit/test_clients_engine.js
+++ b/services/sync/tests/unit/test_clients_engine.js
@@ -125,7 +125,7 @@ add_task(async function test_bad_hmac() {
     check_clients_count(0);
     await syncClientsEngine(server);
     check_clients_count(1);
-    ok(engine.lastRecordUpload > 0);
+    Assert.greater(engine.lastRecordUpload, 0);
     ok(!engine.isFirstSync);
 
     // Our uploaded record has a version.
@@ -275,7 +275,7 @@ add_task(async function test_full_sync() {
     strictEqual(engine.lastRecordUpload, 0);
     ok(engine.isFirstSync);
     await syncClientsEngine(server);
-    ok(engine.lastRecordUpload > 0);
+    Assert.greater(engine.lastRecordUpload, 0);
     ok(!engine.isFirstSync);
     deepEqual(
       user.collection("clients").keys().sort(),
@@ -333,7 +333,7 @@ add_task(async function test_sync() {
     ok(engine.isFirstSync);
     await syncClientsEngine(server);
     ok(!!clientWBO().payload);
-    ok(engine.lastRecordUpload > 0);
+    Assert.greater(engine.lastRecordUpload, 0);
     ok(!engine.isFirstSync);
 
     _(
@@ -344,7 +344,7 @@ add_task(async function test_sync() {
     clientWBO().payload = undefined;
     await syncClientsEngine(server);
     ok(!!clientWBO().payload);
-    ok(engine.lastRecordUpload > lastweek);
+    Assert.greater(engine.lastRecordUpload, lastweek);
     ok(!engine.isFirstSync);
 
     _("Remove client record.");
@@ -394,8 +394,8 @@ add_task(async function test_client_name_change() {
   changedIDs = await tracker.getChangedIDs();
   equal(Object.keys(changedIDs).length, 1);
   ok(engine.localID in changedIDs);
-  ok(tracker.score > initialScore);
-  ok(tracker.score >= SCORE_INCREMENT_XLARGE);
+  Assert.greater(tracker.score, initialScore);
+  Assert.greaterOrEqual(tracker.score, SCORE_INCREMENT_XLARGE);
 
   await tracker.stop();
 
@@ -425,8 +425,8 @@ add_task(async function test_fxa_device_id_change() {
   changedIDs = await tracker.getChangedIDs();
   equal(Object.keys(changedIDs).length, 1);
   ok(engine.localID in changedIDs);
-  ok(tracker.score > initialScore);
-  ok(tracker.score >= SINGLE_USER_THRESHOLD);
+  Assert.greater(tracker.score, initialScore);
+  Assert.greaterOrEqual(tracker.score, SINGLE_USER_THRESHOLD);
 
   await tracker.stop();
 
@@ -477,7 +477,10 @@ add_task(async function test_last_modified() {
     await engine._uploadOutgoing();
 
     _("Local record should have updated timestamp");
-    ok(engine._store._remoteClients[activeID].serverLastModified >= now);
+    Assert.greaterOrEqual(
+      engine._store._remoteClients[activeID].serverLastModified,
+      now
+    );
 
     _("Record on the server should have new name but not serverLastModified");
     let payload = collection.cleartext(activeID);
@@ -732,7 +735,7 @@ add_task(async function test_filter_duplicate_names() {
     strictEqual(engine.lastRecordUpload, 0);
     ok(engine.isFirstSync);
     await syncClientsEngine(server);
-    ok(engine.lastRecordUpload > 0);
+    Assert.greater(engine.lastRecordUpload, 0);
     ok(!engine.isFirstSync);
     deepEqual(
       user.collection("clients").keys().sort(),
@@ -776,7 +779,7 @@ add_task(async function test_filter_duplicate_names() {
 
     // Check that a subsequent Sync doesn't report anything as being processed.
     let counts;
-    Svc.Obs.add("weave:engine:sync:applied", function observe(subject, data) {
+    Svc.Obs.add("weave:engine:sync:applied", function observe(subject) {
       Svc.Obs.remove("weave:engine:sync:applied", observe);
       counts = subject;
     });
@@ -915,7 +918,7 @@ add_task(async function test_command_sync() {
 
     _("Checking record was uploaded.");
     notEqual(clientWBO(engine.localID).payload, undefined);
-    ok(engine.lastRecordUpload > 0);
+    Assert.greater(engine.lastRecordUpload, 0);
     ok(!engine.isFirstSync);
 
     notEqual(clientWBO(remoteId).payload, undefined);
diff --git a/services/sync/tests/unit/test_declined.js b/services/sync/tests/unit/test_declined.js
index af7f8eb8c5..aecd33ee6e 100644
--- a/services/sync/tests/unit/test_declined.js
+++ b/services/sync/tests/unit/test_declined.js
@@ -79,7 +79,7 @@ add_task(async function testOldMeta() {
 
   let declinedEngines = new DeclinedEngines(Service);
 
-  function onNotDeclined(subject, topic, data) {
+  function onNotDeclined(subject) {
     Observers.remove("weave:engines:notdeclined", onNotDeclined);
     Assert.ok(
       subject.undecided.has("actual"),
@@ -129,7 +129,7 @@ add_task(async function testDeclinedMeta() {
 
   let declinedEngines = new DeclinedEngines(Service);
 
-  function onNotDeclined(subject, topic, data) {
+  function onNotDeclined(subject) {
     Observers.remove("weave:engines:notdeclined", onNotDeclined);
     Assert.ok(
       subject.undecided.has("actual"),
diff --git a/services/sync/tests/unit/test_engine_abort.js b/services/sync/tests/unit/test_engine_abort.js
index f9bbf9d338..a7c62afb4a 100644
--- a/services/sync/tests/unit/test_engine_abort.js
+++ b/services/sync/tests/unit/test_engine_abort.js
@@ -37,7 +37,7 @@ add_task(async function test_processIncoming_abort() {
   );
   meta_global.payload.engines = { rotary: { version: engine.version, syncID } };
   _("Fake applyIncoming to abort.");
-  engine._store.applyIncoming = async function (record) {
+  engine._store.applyIncoming = async function () {
     let ex = {
       code: SyncEngine.prototype.eEngineAbortApplyIncoming,
       cause: "Nooo",
diff --git a/services/sync/tests/unit/test_errorhandler_1.js b/services/sync/tests/unit/test_errorhandler_1.js
index 2d52b93a02..f5e96ed44e 100644
--- a/services/sync/tests/unit/test_errorhandler_1.js
+++ b/services/sync/tests/unit/test_errorhandler_1.js
@@ -286,13 +286,10 @@ add_task(async function test_info_collections_login_server_maintenance_error() {
   await configureIdentity({ username: "broken.info" }, server);
 
   let backoffInterval;
-  Svc.Obs.add(
-    "weave:service:backoff:interval",
-    function observe(subject, data) {
-      Svc.Obs.remove("weave:service:backoff:interval", observe);
-      backoffInterval = subject;
-    }
-  );
+  Svc.Obs.add("weave:service:backoff:interval", function observe(subject) {
+    Svc.Obs.remove("weave:service:backoff:interval", observe);
+    backoffInterval = subject;
+  });
 
   Assert.ok(!Status.enforceBackoff);
   Assert.equal(Status.service, STATUS_OK);
@@ -318,13 +315,10 @@ add_task(async function test_meta_global_login_server_maintenance_error() {
   await configureIdentity({ username: "broken.meta" }, server);
 
   let backoffInterval;
-  Svc.Obs.add(
-    "weave:service:backoff:interval",
-    function observe(subject, data) {
-      Svc.Obs.remove("weave:service:backoff:interval", observe);
-      backoffInterval = subject;
-    }
-  );
+  Svc.Obs.add("weave:service:backoff:interval", function observe(subject) {
+    Svc.Obs.remove("weave:service:backoff:interval", observe);
+    backoffInterval = subject;
+  });
 
   Assert.ok(!Status.enforceBackoff);
   Assert.equal(Status.service, STATUS_OK);
diff --git a/services/sync/tests/unit/test_errorhandler_2.js b/services/sync/tests/unit/test_errorhandler_2.js
index 5cab4d832d..2a7e6ba619 100644
--- a/services/sync/tests/unit/test_errorhandler_2.js
+++ b/services/sync/tests/unit/test_errorhandler_2.js
@@ -74,13 +74,10 @@ add_task(async function test_crypto_keys_login_server_maintenance_error() {
   Service.collectionKeys.clear();
 
   let backoffInterval;
-  Svc.Obs.add(
-    "weave:service:backoff:interval",
-    function observe(subject, data) {
-      Svc.Obs.remove("weave:service:backoff:interval", observe);
-      backoffInterval = subject;
-    }
-  );
+  Svc.Obs.add("weave:service:backoff:interval", function observe(subject) {
+    Svc.Obs.remove("weave:service:backoff:interval", observe);
+    backoffInterval = subject;
+  });
 
   Assert.ok(!Status.enforceBackoff);
   Assert.equal(Status.service, STATUS_OK);
@@ -178,13 +175,10 @@ add_task(
     await configureIdentity({ username: "broken.info" }, server);
 
     let backoffInterval;
-    Svc.Obs.add(
-      "weave:service:backoff:interval",
-      function observe(subject, data) {
-        Svc.Obs.remove("weave:service:backoff:interval", observe);
-        backoffInterval = subject;
-      }
-    );
+    Svc.Obs.add("weave:service:backoff:interval", function observe(subject) {
+      Svc.Obs.remove("weave:service:backoff:interval", observe);
+      backoffInterval = subject;
+    });
 
     Assert.ok(!Status.enforceBackoff);
     Assert.equal(Status.service, STATUS_OK);
@@ -215,13 +209,10 @@ add_task(
     await configureIdentity({ username: "broken.meta" }, server);
 
     let backoffInterval;
-    Svc.Obs.add(
-      "weave:service:backoff:interval",
-      function observe(subject, data) {
-        Svc.Obs.remove("weave:service:backoff:interval", observe);
-        backoffInterval = subject;
-      }
-    );
+    Svc.Obs.add("weave:service:backoff:interval", function observe(subject) {
+      Svc.Obs.remove("weave:service:backoff:interval", observe);
+      backoffInterval = subject;
+    });
 
     Assert.ok(!Status.enforceBackoff);
     Assert.equal(Status.service, STATUS_OK);
@@ -254,13 +245,10 @@ add_task(
     Service.collectionKeys.clear();
 
     let backoffInterval;
-    Svc.Obs.add(
-      "weave:service:backoff:interval",
-      function observe(subject, data) {
-        Svc.Obs.remove("weave:service:backoff:interval", observe);
-        backoffInterval = subject;
-      }
-    );
+    Svc.Obs.add("weave:service:backoff:interval", function observe(subject) {
+      Svc.Obs.remove("weave:service:backoff:interval", observe);
+      backoffInterval = subject;
+    });
 
     Assert.ok(!Status.enforceBackoff);
     Assert.equal(Status.service, STATUS_OK);
@@ -291,13 +279,10 @@ add_task(
     await configureIdentity({ username: "broken.keys" }, server);
 
     let backoffInterval;
-    Svc.Obs.add(
-      "weave:service:backoff:interval",
-      function observe(subject, data) {
-        Svc.Obs.remove("weave:service:backoff:interval", observe);
-        backoffInterval = subject;
-      }
-    );
+    Svc.Obs.add("weave:service:backoff:interval", function observe(subject) {
+      Svc.Obs.remove("weave:service:backoff:interval", observe);
+      backoffInterval = subject;
+    });
 
     Assert.ok(!Status.enforceBackoff);
     Assert.equal(Status.service, STATUS_OK);
@@ -328,13 +313,10 @@ add_task(
     await configureIdentity({ username: "broken.wipe" }, server);
 
     let backoffInterval;
-    Svc.Obs.add(
-      "weave:service:backoff:interval",
-      function observe(subject, data) {
-        Svc.Obs.remove("weave:service:backoff:interval", observe);
-        backoffInterval = subject;
-      }
-    );
+    Svc.Obs.add("weave:service:backoff:interval", function observe(subject) {
+      Svc.Obs.remove("weave:service:backoff:interval", observe);
+      backoffInterval = subject;
+    });
 
     Assert.ok(!Status.enforceBackoff);
     Assert.equal(Status.service, STATUS_OK);
@@ -368,13 +350,10 @@ add_task(
     engine.enabled = true;
 
     let backoffInterval;
-    Svc.Obs.add(
-      "weave:service:backoff:interval",
-      function observe(subject, data) {
-        Svc.Obs.remove("weave:service:backoff:interval", observe);
-        backoffInterval = subject;
-      }
-    );
+    Svc.Obs.add("weave:service:backoff:interval", function observe(subject) {
+      Svc.Obs.remove("weave:service:backoff:interval", observe);
+      backoffInterval = subject;
+    });
 
     Assert.ok(!Status.enforceBackoff);
     Assert.equal(Status.service, STATUS_OK);
diff --git a/services/sync/tests/unit/test_errorhandler_filelog.js b/services/sync/tests/unit/test_errorhandler_filelog.js
index 66260b3f59..357049276c 100644
--- a/services/sync/tests/unit/test_errorhandler_filelog.js
+++ b/services/sync/tests/unit/test_errorhandler_filelog.js
@@ -82,7 +82,7 @@ function readFile(file, callback) {
       uri: NetUtil.newURI(file),
       loadUsingSystemPrincipal: true,
     },
-    function (inputStream, statusCode, request) {
+    function (inputStream, statusCode) {
       let data = NetUtil.readInputStreamToString(
         inputStream,
         inputStream.available()
diff --git a/services/sync/tests/unit/test_fxa_node_reassignment.js b/services/sync/tests/unit/test_fxa_node_reassignment.js
index 0b25df0183..0fa7ee922c 100644
--- a/services/sync/tests/unit/test_fxa_node_reassignment.js
+++ b/services/sync/tests/unit/test_fxa_node_reassignment.js
@@ -46,7 +46,7 @@ function prepareServer(cbAfterTokenFetch) {
   // A server callback to ensure we don't accidentally hit the wrong endpoint
   // after a node reassignment.
   let callback = {
-    onRequest(req, resp) {
+    onRequest(req) {
       let full = `${req.scheme}://${req.host}:${req.port}${req.path}`;
       let expected = config.fxaccount.token.endpoint;
       Assert.ok(
diff --git a/services/sync/tests/unit/test_history_engine.js b/services/sync/tests/unit/test_history_engine.js
index 9cca379b0b..259338df09 100644
--- a/services/sync/tests/unit/test_history_engine.js
+++ b/services/sync/tests/unit/test_history_engine.js
@@ -16,13 +16,13 @@ XPCOMUtils.defineLazyServiceGetter(
   "mozIAsyncHistory"
 );
 async function rawAddVisit(id, uri, visitPRTime, transitionType) {
-  return new Promise((resolve, reject) => {
+  return new Promise(resolve => {
     let results = [];
     let handler = {
       handleResult(result) {
         results.push(result);
       },
-      handleError(resultCode, placeInfo) {
+      handleError(resultCode) {
         do_throw(`updatePlaces gave error ${resultCode}!`);
       },
       handleCompletion(count) {
diff --git a/services/sync/tests/unit/test_history_store.js b/services/sync/tests/unit/test_history_store.js
index 07aee0dd01..1777664bb6 100644
--- a/services/sync/tests/unit/test_history_store.js
+++ b/services/sync/tests/unit/test_history_store.js
@@ -17,7 +17,7 @@ const TIMESTAMP3 = (Date.now() - 123894) * 1000;
 
 function promiseOnVisitObserved() {
   return new Promise(res => {
-    let listener = new PlacesWeakCallbackWrapper(events => {
+    let listener = new PlacesWeakCallbackWrapper(() => {
       PlacesObservers.removeListener(["page-visited"], listener);
       res();
     });
diff --git a/services/sync/tests/unit/test_history_tracker.js b/services/sync/tests/unit/test_history_tracker.js
index 6f351d6984..64433574b4 100644
--- a/services/sync/tests/unit/test_history_tracker.js
+++ b/services/sync/tests/unit/test_history_tracker.js
@@ -37,7 +37,7 @@ async function verifyTrackedItems(tracked) {
   let trackedIDs = new Set(Object.keys(changes));
   for (let guid of tracked) {
     ok(guid in changes, `${guid} should be tracked`);
-    ok(changes[guid] > 0, `${guid} should have a modified time`);
+    Assert.greater(changes[guid], 0, `${guid} should have a modified time`);
     trackedIDs.delete(guid);
   }
   equal(
@@ -160,7 +160,7 @@ add_task(async function test_dont_track_expiration() {
   let scorePromise = promiseOneObserver("weave:engine:score:updated");
 
   // Observe expiration.
-  Services.obs.addObserver(function onExpiration(aSubject, aTopic, aData) {
+  Services.obs.addObserver(function onExpiration(aSubject, aTopic) {
     Services.obs.removeObserver(onExpiration, aTopic);
     // Remove the remaining page to update its score.
     PlacesUtils.history.remove(uriToRemove);
diff --git a/services/sync/tests/unit/test_hmac_error.js b/services/sync/tests/unit/test_hmac_error.js
index 26dbc12dea..a04e54f476 100644
--- a/services/sync/tests/unit/test_hmac_error.js
+++ b/services/sync/tests/unit/test_hmac_error.js
@@ -171,7 +171,7 @@ add_task(async function hmac_error_during_node_reassignment() {
   }
   let onSyncFinished = function () {};
   let obs = {
-    observe: function observe(subject, topic, data) {
+    observe: function observe(subject, topic) {
       switch (topic) {
         case "weave:service:sync:error":
           onSyncError();
diff --git a/services/sync/tests/unit/test_httpd_sync_server.js b/services/sync/tests/unit/test_httpd_sync_server.js
index 6ac8ff5e04..23bb05b15d 100644
--- a/services/sync/tests/unit/test_httpd_sync_server.js
+++ b/services/sync/tests/unit/test_httpd_sync_server.js
@@ -160,7 +160,7 @@ add_task(async function test_storage_request() {
 
   async function deleteWBONotExists() {
     let req = localRequest(server, keysURL);
-    server.callback.onItemDeleted = function (username, collection, wboID) {
+    server.callback.onItemDeleted = function () {
       do_throw("onItemDeleted should not have been called.");
     };
 
diff --git a/services/sync/tests/unit/test_interval_triggers.js b/services/sync/tests/unit/test_interval_triggers.js
index 6f2821ec45..eb0b39f636 100644
--- a/services/sync/tests/unit/test_interval_triggers.js
+++ b/services/sync/tests/unit/test_interval_triggers.js
@@ -51,7 +51,7 @@ add_task(async function setup() {
   // Don't remove stale clients when syncing. This is a test-only workaround
   // that lets us add clients directly to the store, without losing them on
   // the next sync.
-  clientsEngine._removeRemoteClient = async id => {};
+  clientsEngine._removeRemoteClient = async () => {};
 });
 
 add_task(async function test_successful_sync_adjustSyncInterval() {
diff --git a/services/sync/tests/unit/test_password_engine.js b/services/sync/tests/unit/test_password_engine.js
index 081403f63d..54fe8972f2 100644
--- a/services/sync/tests/unit/test_password_engine.js
+++ b/services/sync/tests/unit/test_password_engine.js
@@ -434,8 +434,9 @@ add_task(async function test_sync_outgoing() {
     equal(deletedLogin.guid, guid, "deleted login guid");
     equal(deletedLogin.everSynced, true, "deleted login everSynced");
     equal(deletedLogin.syncCounter, 0, "deleted login syncCounter");
-    ok(
-      deletedLogin.timePasswordChanged > 0,
+    Assert.greater(
+      deletedLogin.timePasswordChanged,
+      0,
       "deleted login timePasswordChanged"
     );
   } finally {
@@ -525,7 +526,7 @@ add_task(async function test_sync_incoming() {
     checkFields.forEach(field => {
       equal(logins[0][field], details[field]);
     });
-    ok(logins[0].timePasswordChanged > details.timePasswordChanged);
+    Assert.greater(logins[0].timePasswordChanged, details.timePasswordChanged);
     equal(logins[0].syncCounter, 0);
     equal(logins[0].everSynced, true);
 
@@ -553,7 +554,7 @@ add_task(async function test_sync_incoming() {
     checkFields.forEach(field => {
       equal(logins[0][field], details[field]);
     });
-    ok(logins[0].timePasswordChanged > details.timePasswordChanged);
+    Assert.greater(logins[0].timePasswordChanged, details.timePasswordChanged);
     equal(logins[0].syncCounter, 0);
     equal(logins[0].everSynced, true);
 
diff --git a/services/sync/tests/unit/test_resource.js b/services/sync/tests/unit/test_resource.js
index 5182784639..5dee57b39a 100644
--- a/services/sync/tests/unit/test_resource.js
+++ b/services/sync/tests/unit/test_resource.js
@@ -480,7 +480,7 @@ add_task(async function test_post_override_content_type() {
 add_task(async function test_weave_backoff() {
   _("X-Weave-Backoff header notifies observer");
   let backoffInterval;
-  function onBackoff(subject, data) {
+  function onBackoff(subject) {
     backoffInterval = subject;
   }
   Observers.add("weave:service:backoff:interval", onBackoff);
diff --git a/services/sync/tests/unit/test_service_sync_401.js b/services/sync/tests/unit/test_service_sync_401.js
index a0bde0b0ab..0c285872e9 100644
--- a/services/sync/tests/unit/test_service_sync_401.js
+++ b/services/sync/tests/unit/test_service_sync_401.js
@@ -48,7 +48,7 @@ add_task(async function run_test() {
     Svc.PrefBranch.setIntPref("lastPing", Math.floor(Date.now() / 1000));
 
     let threw = false;
-    Svc.Obs.add("weave:service:sync:error", function (subject, data) {
+    Svc.Obs.add("weave:service:sync:error", function () {
       threw = true;
     });
 
diff --git a/services/sync/tests/unit/test_service_verifyLogin.js b/services/sync/tests/unit/test_service_verifyLogin.js
index b99b5c692c..b3afe6179a 100644
--- a/services/sync/tests/unit/test_service_verifyLogin.js
+++ b/services/sync/tests/unit/test_service_verifyLogin.js
@@ -78,13 +78,10 @@ add_task(async function test_verifyLogin() {
     Service._updateCachedURLs();
     Assert.ok(!Service.status.enforceBackoff);
     let backoffInterval;
-    Svc.Obs.add(
-      "weave:service:backoff:interval",
-      function observe(subject, data) {
-        Svc.Obs.remove("weave:service:backoff:interval", observe);
-        backoffInterval = subject;
-      }
-    );
+    Svc.Obs.add("weave:service:backoff:interval", function observe(subject) {
+      Svc.Obs.remove("weave:service:backoff:interval", observe);
+      backoffInterval = subject;
+    });
     Assert.equal(false, await Service.verifyLogin());
     Assert.ok(Service.status.enforceBackoff);
     Assert.equal(backoffInterval, 42);
diff --git a/services/sync/tests/unit/test_sync_auth_manager.js b/services/sync/tests/unit/test_sync_auth_manager.js
index 9af40d26c6..f9fa669667 100644
--- a/services/sync/tests/unit/test_sync_auth_manager.js
+++ b/services/sync/tests/unit/test_sync_auth_manager.js
@@ -37,9 +37,8 @@ const { TokenServerClient, TokenServerClientServerError } =
   ChromeUtils.importESModule(
     "resource://services-common/tokenserverclient.sys.mjs"
   );
-const { AccountState } = ChromeUtils.importESModule(
-  "resource://gre/modules/FxAccounts.sys.mjs"
-);
+const { AccountState, ERROR_INVALID_ACCOUNT_STATE } =
+  ChromeUtils.importESModule("resource://gre/modules/FxAccounts.sys.mjs");
 
 const SECOND_MS = 1000;
 const MINUTE_MS = SECOND_MS * 60;
@@ -192,8 +191,11 @@ add_task(async function test_initialializeWithAuthErrorAndDeletedAccount() {
 
   await Assert.rejects(
     syncAuthManager._ensureValidToken(),
-    AuthenticationError,
-    "should reject due to an auth error"
+    err => {
+      Assert.equal(err.message, ERROR_INVALID_ACCOUNT_STATE);
+      return true; // expected error
+    },
+    "should reject because the account was deleted"
   );
 
   Assert.ok(accessTokenWithSessionTokenCalled);
@@ -801,14 +803,11 @@ add_task(async function test_getKeysMissing() {
       storageManager.initialize(identityConfig.fxaccount.user);
       return new AccountState(storageManager);
     },
-    // And the keys object with a mock that returns no keys.
-    keys: {
-      getKeyForScope() {
-        return Promise.resolve(null);
-      },
-    },
   });
-
+  fxa.getOAuthTokenAndKey = () => {
+    // And the keys object with a mock that returns no keys.
+    return Promise.resolve({ key: null, token: "fake token" });
+  };
   syncAuthManager._fxaService = fxa;
 
   await Assert.rejects(
@@ -844,14 +843,12 @@ add_task(async function test_getKeysUnexpecedError() {
       storageManager.initialize(identityConfig.fxaccount.user);
       return new AccountState(storageManager);
     },
-    // And the keys object with a mock that returns no keys.
-    keys: {
-      async getKeyForScope() {
-        throw new Error("well that was unexpected");
-      },
-    },
   });
 
+  fxa.getOAuthTokenAndKey = () => {
+    return Promise.reject("well that was unexpected");
+  };
+
   syncAuthManager._fxaService = fxa;
 
   await Assert.rejects(
@@ -1005,7 +1002,7 @@ function mockTokenServer(func) {
     requestLog.addAppender(new Log.DumpAppender());
     requestLog.level = Log.Level.Trace;
   }
-  function MockRESTRequest(url) {}
+  function MockRESTRequest() {}
   MockRESTRequest.prototype = {
     _log: requestLog,
     setHeader() {},
diff --git a/services/sync/tests/unit/test_syncedtabs.js b/services/sync/tests/unit/test_syncedtabs.js
index 79ab3e0686..c915e12602 100644
--- a/services/sync/tests/unit/test_syncedtabs.js
+++ b/services/sync/tests/unit/test_syncedtabs.js
@@ -87,7 +87,7 @@ let MockClientsEngine = {
     return tabsEngine.clients[id].fxaDeviceId;
   },
 
-  getClientType(id) {
+  getClientType() {
     return "desktop";
   },
 };
diff --git a/services/sync/tests/unit/test_syncscheduler.js b/services/sync/tests/unit/test_syncscheduler.js
index 98b7937da3..8eb1ea3f40 100644
--- a/services/sync/tests/unit/test_syncscheduler.js
+++ b/services/sync/tests/unit/test_syncscheduler.js
@@ -92,7 +92,7 @@ add_task(async function setup() {
   // Don't remove stale clients when syncing. This is a test-only workaround
   // that lets us add clients directly to the store, without losing them on
   // the next sync.
-  clientsEngine._removeRemoteClient = async id => {};
+  clientsEngine._removeRemoteClient = async () => {};
   await Service.engineManager.clear();
 
   validate_all_future_pings();
diff --git a/services/sync/tests/unit/test_tab_quickwrite.js b/services/sync/tests/unit/test_tab_quickwrite.js
index 2a1c75c8c6..c363992d66 100644
--- a/services/sync/tests/unit/test_tab_quickwrite.js
+++ b/services/sync/tests/unit/test_tab_quickwrite.js
@@ -179,7 +179,7 @@ add_task(async function test_tab_quickWrite_telemetry() {
   let telem = get_sync_test_telemetry();
   telem.payloads = [];
   let oldSubmit = telem.submit;
-  let submitPromise = new Promise((resolve, reject) => {
+  let submitPromise = new Promise(resolve => {
     telem.submit = function (ping) {
       telem.submit = oldSubmit;
       resolve(ping);
diff --git a/services/sync/tests/unit/test_telemetry.js b/services/sync/tests/unit/test_telemetry.js
index 961e96a01b..4f3a4e7c2b 100644
--- a/services/sync/tests/unit/test_telemetry.js
+++ b/services/sync/tests/unit/test_telemetry.js
@@ -734,7 +734,7 @@ add_task(async function test_clean_real_os_error() {
       equal(failureReason.name, "unexpectederror");
       equal(
         failureReason.error,
-        "OS error [File/Path not found] Could not open the file at [profileDir]/no/such/path.json"
+        "OS error [File/Path not found] Could not open `[profileDir]/no/such/path.json': file does not exist"
       );
     });
   } finally {
@@ -1351,7 +1351,7 @@ add_task(async function test_no_node_type() {
   await configureIdentity(null, server);
 
   await sync_and_validate_telem(ping => {
-    ok(ping.syncNodeType === undefined);
+    Assert.strictEqual(ping.syncNodeType, undefined);
   }, true);
   await promiseStopServer(server);
 });
diff --git a/services/sync/tests/unit/test_uistate.js b/services/sync/tests/unit/test_uistate.js
index cb1ff1979e..136f274a71 100644
--- a/services/sync/tests/unit/test_uistate.js
+++ b/services/sync/tests/unit/test_uistate.js
@@ -292,7 +292,7 @@ add_task(async function test_syncFinished() {
 
   const newState = Object.assign({}, UIState.get());
   ok(!newState.syncing);
-  ok(new Date(newState.lastSync) > new Date(oldState.lastSync));
+  Assert.greater(new Date(newState.lastSync), new Date(oldState.lastSync));
 });
 
 add_task(async function test_syncError() {
@@ -314,7 +314,7 @@ add_task(async function test_syncError() {
 
 function observeUIUpdate() {
   return new Promise(resolve => {
-    let obs = (aSubject, aTopic, aData) => {
+    let obs = (aSubject, aTopic) => {
       Services.obs.removeObserver(obs, aTopic);
       const state = UIState.get();
       resolve(state);
diff --git a/services/sync/tps/extensions/tps/resource/modules/bookmarkValidator.sys.mjs b/services/sync/tps/extensions/tps/resource/modules/bookmarkValidator.sys.mjs
index a7724c6aaa..b78e31ab79 100644
--- a/services/sync/tps/extensions/tps/resource/modules/bookmarkValidator.sys.mjs
+++ b/services/sync/tps/extensions/tps/resource/modules/bookmarkValidator.sys.mjs
@@ -602,7 +602,7 @@ class ServerRecordInspection {
 
     await lazy.Async.yieldingForEach(
       this.liveRecords,
-      (record, i) => {
+      record => {
         if (!seen.has(record.id)) {
           // We intentionally don't record the parentid here, since we only record
           // that if the record refers to a parent that doesn't exist, which we
diff --git a/services/sync/tps/extensions/tps/resource/modules/tabs.sys.mjs b/services/sync/tps/extensions/tps/resource/modules/tabs.sys.mjs
index 8ea8f3b780..5ac25dbb4c 100644
--- a/services/sync/tps/extensions/tps/resource/modules/tabs.sys.mjs
+++ b/services/sync/tps/extensions/tps/resource/modules/tabs.sys.mjs
@@ -44,7 +44,7 @@ export var BrowserTabs = {
     // Wait for the tab to load.
     await new Promise(resolve => {
       let mm = browser.ownerGlobal.messageManager;
-      mm.addMessageListener("tps:loadEvent", function onLoad(msg) {
+      mm.addMessageListener("tps:loadEvent", function onLoad() {
         mm.removeMessageListener("tps:loadEvent", onLoad);
         resolve();
       });
diff --git a/services/sync/tps/extensions/tps/resource/modules/windows.sys.mjs b/services/sync/tps/extensions/tps/resource/modules/windows.sys.mjs
index b0798b9031..22c2f47ec9 100644
--- a/services/sync/tps/extensions/tps/resource/modules/windows.sys.mjs
+++ b/services/sync/tps/extensions/tps/resource/modules/windows.sys.mjs
@@ -16,7 +16,7 @@ export var BrowserWindows = {
    * @param aPrivate The private option.
    * @return nothing
    */
-  Add(aPrivate, fn) {
+  Add(aPrivate) {
     return new Promise(resolve => {
       let mainWindow = Services.wm.getMostRecentWindow("navigator:browser");
       let win = mainWindow.OpenBrowserWindow({ private: aPrivate });
diff --git a/services/sync/tps/extensions/tps/resource/tps.sys.mjs b/services/sync/tps/extensions/tps/resource/tps.sys.mjs
index 2c4a5994a6..449ca27411 100644
--- a/services/sync/tps/extensions/tps/resource/tps.sys.mjs
+++ b/services/sync/tps/extensions/tps/resource/tps.sys.mjs
@@ -168,7 +168,7 @@ export var TPS = {
     "nsISupportsWeakReference",
   ]),
 
-  observe: function TPS__observe(subject, topic, data) {
+  observe: function TPS__observe(subject, topic) {
     try {
       lazy.Logger.logInfo("----------event observed: " + topic);