ChromeOS Personalization

User Types and Profiles

ChromeOS Personalization features interact differently with different user types. It is important for feature development to consider how the different user types will be affected.

see: //components/user_manager/user_type.h

For a more in depth explanation, see:

Profiles, Sessions, Users, and more for ChromeOS Personalization

Tests

Background

Personalization App takes a layered approach to testing. There are C++ unit tests, javascript component browser tests, and javascript full-app browsertests.

• mojom handler unit tests
  • //chrome/browser/ash/system_web_apps/apps/personalization_app/*unittest.cc
  • unit_tests --gtest_filter=*PersonalizationApp*
  • primarily to test behavior of mojom handlers
  • heavily mocked out ash environment
    • fake user manager
    • fake wallpaper_controller
    • etc
• component browser tests
  • personalization_app_component_browsertest.cc
  • browser_tests --gtest_filter=*PersonalizationAppComponent*
  • loads test cases from //chrome/test/data/webui/chromeos/personalization_app/*
  • Opens an empty browser window, loads javascript necessary to render a single Polymer element, and executes javascript tests against that component
  • All mojom calls are faked in javascript
    • any mojom call that reaches personalization_app_mojom_banned_mocha_test_base.h will immediately fail the test
• controller browser tests
  • personalization_app_controller_browsertest.cc
  • browser_tests --gtest_filter=*PersonalizationAppController*
  • no UI elements, javascript testing of controller functions, reducers, logic
  • All mojom calls are faked in javascript the same way as component browser tests
• app browser tests
  • personalization_app_test.ts
  • browser_tests --gtest_filter=*PersonalizationAppBrowserTest
  • Uses fixture personalization_app_mocha_test_base.h
    • wallpaper mocked out at network layer by mocking out wallpaper fetchers via TestWallpaperFetcherDelegate
    • uses a real theme provider
    • all others mock out mojom layer via fake mojom providers FakePersonalizationApp{Ambient,KeyboardBacklight,User}Provider
• System Web App integration tests
  • personalization_app_integration_browsertest.cc
  • browser_tests --gtest_filter=*PersonalizationAppIntegration*
  • Tests that the app install, launches without error
  • Also tests special tricky system UI support for full screen transparency for wallpaper preview because they cannot be tested in javascript
    • includes a pixel test for fullscreen wallpaper preview
    • see below Running browser pixel tests and //ash/test/pixel/README.md for more information

Running browser pixel tests

Locally

browser_tests
--gtest_filter=*PersonalizationAppIntegrationPixel*
--skia-gold-local-png-write-directory=/tmp/skia_gold/
--enable-pixel-output-in-tests
--browser-ui-tests-verify-pixels

Inspect the output pngs generated in /tmp/skia_gold/* to make sure that the test is setting up the correct UI state.

CQ

In CQ these tests do not actually verify pixel output as part of the mainline browser_tests step in linux-chromeos-rel. However, they still go through the setup to make sure there are no crashes while preparing the UI. Full pixel verification will run as part of pixel_experimental_browser_tests which passes the necessary additional argument --browser-ui-tests-verify-pixels.

Where should I write my test?

• complex behavior that involves multiple parts of the application and mojom handlers
  • app browser tests
• a single javascript component
  • component browser tests
• javascript logic and state management
  • controller browser tests
• mojom handling logic
  • mojom handler unit tests

Debugging tests

• Debugging BrowserTest failures.
• The browser test doc has some useful information.
• Inject debugger; as a breakpoint.
• Run a specific test/test suite: test("test name", () => ...) => test.only("test name"...).
• Debug flaky tests: Pass flags --gtest_repeat=1000 --gtest_break_on_failure.

Environment Setup

VSCode

• Follow vscode setup.
  • (Optional) Set up code-server for remote development.
• Create tsconfig.json using helper script. Please follow the help doc in the header of the helper script.
• Edit ${PATH_TO_CHROMIUM}/src/.git/info/exclude and add these lines

  /ash/webui/personalization_app/resources/tsconfig.json
  /chrome/test/data/webui/chromeos/personalization_app/tsconfig.json