Bug 1885992 - Test that BackupService.takeMeasurements calls measure on each BackupResource. r=backup-reviewers,fchasen

This also fixes a small typo that prevented us from properly being able
to override the built-in default BackupResources while testing.

Differential Revision: https://phabricator.services.mozilla.com/D204966

browser/components/backup/BackupService.sys.mjs

@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-import * as BackupResources from "resource:///modules/backup/BackupResources.sys.mjs";
+import * as DefaultBackupResources from "resource:///modules/backup/BackupResources.sys.mjs";
 
 const lazy = {};
 
@@ -48,7 +48,7 @@ export class BackupService {
     if (this.#instance) {
       return this.#instance;
     }
-    this.#instance = new BackupService(BackupResources);
+    this.#instance = new BackupService(DefaultBackupResources);
     this.#instance.takeMeasurements();
 
     return this.#instance;
@@ -57,13 +57,13 @@ export class BackupService {
   /**
    * Create a BackupService instance.
    *
-   * @param {object} [backupResources=BackupResources] - Object containing BackupResource classes to associate with this service.
+   * @param {object} [backupResources=DefaultBackupResources] - Object containing BackupResource classes to associate with this service.
    */
-  constructor(backupResources = BackupResources) {
+  constructor(backupResources = DefaultBackupResources) {
     lazy.logConsole.debug("Instantiated");
 
     for (const resourceName in backupResources) {
-      let resource = BackupResources[resourceName];
+      let resource = backupResources[resourceName];
       this.#resources.set(resource.key, resource);
     }
   }
@@ -97,7 +97,14 @@ export class BackupService {
 
     // Measure the size of each file we are going to backup.
     for (let resourceClass of this.#resources.values()) {
-      await new resourceClass().measure(PathUtils.profileDir);
+      try {
+        await new resourceClass().measure(PathUtils.profileDir);
+      } catch (e) {
+        lazy.logConsole.error(
+          `Failed to measure for resource: ${resourceClass.key}`,
+          e
+        );
+      }
     }
   }
 }

browser/components/backup/tests/xpcshell/test_measurements.js

@@ -6,13 +6,23 @@ http://creativecommons.org/publicdomain/zero/1.0/ */
 const { BackupService } = ChromeUtils.importESModule(
   "resource:///modules/backup/BackupService.sys.mjs"
 );
+
 const { PlacesBackupResource } = ChromeUtils.importESModule(
   "resource:///modules/backup/PlacesBackupResource.sys.mjs"
 );
+
+const { BackupResource } = ChromeUtils.importESModule(
+  "resource:///modules/backup/BackupResource.sys.mjs"
+);
+
 const { TelemetryTestUtils } = ChromeUtils.importESModule(
   "resource://testing-common/TelemetryTestUtils.sys.mjs"
 );
 
+const { sinon } = ChromeUtils.importESModule(
+  "resource://testing-common/Sinon.sys.mjs"
+);
+
 const EXPECTED_PLACES_DB_SIZE = 5240;
 const EXPECTED_FAVICONS_DB_SIZE = 5240;
 
@@ -23,6 +33,54 @@ add_setup(() => {
   Services.telemetry.clearScalars();
 });
 
+/**
+ * Tests that calling `BackupService.takeMeasurements` will call the measure
+ * method of all registered BackupResource classes.
+ */
+add_task(async function test_takeMeasurements() {
+  /**
+   * Some fake backup resource classes to test with.
+   */
+  class FakeBackupResource1 extends BackupResource {
+    static get key() {
+      return "fake1";
+    }
+    measure() {}
+  }
+
+  /**
+   * Another fake backup resource class to test with.
+   */
+  class FakeBackupResource2 extends BackupResource {
+    static get key() {
+      return "fake2";
+    }
+    measure() {}
+  }
+
+  let sandbox = sinon.createSandbox();
+  sandbox.stub(FakeBackupResource1.prototype, "measure").resolves();
+  sandbox
+    .stub(FakeBackupResource2.prototype, "measure")
+    .rejects(new Error("Some failure to measure"));
+
+  let bs = new BackupService({ FakeBackupResource1, FakeBackupResource2 });
+  await bs.takeMeasurements();
+
+  for (let backupResourceClass of [FakeBackupResource1, FakeBackupResource2]) {
+    Assert.ok(
+      backupResourceClass.prototype.measure.calledOnce,
+      "Measure was called"
+    );
+    Assert.ok(
+      backupResourceClass.prototype.measure.calledWith(PathUtils.profileDir),
+      "Measure was called with the profile directory argument"
+    );
+  }
+
+  sandbox.restore();
+});
+
 /**
  * Tests that we can measure the disk space available in the profile directory.
  */