flutter scenic embedder tests

Configure and build fuchsia

For tests that require scenic, for example, run fx set with the required targets; for example:

$ cd "$FUCHSIA_DIR"
$ fx set core.x64 \
    --with //src/ui/scenic \
    --with //src/ui/bin/root_presenter \
    --with //src/ui/bin/hardware_display_controller_provider
$ fx build

Note 1: You could use --with-base here, instead of --with, but if so, you would also need to add --with-base //garnet/packages/testing:run_test_component. More on this below, under Start the package servers.

Note 2: The fx set flags, above, offer a minimized fuchsia platform configuration to successfully execute the test, but some optional services may be missing. Be aware that the Fuchsia system logs may include multiple occurrences WARNING: error resolving ... messages, such as the following, which can be ignored:

[pkg-resolver] WARNING: error resolving fuchsia-pkg://fuchsia.com/fonts/0 ...
[pkg-resolver] WARNING: error resolving fuchsia-pkg://fuchsia.com/ime_service/0 ...
[pkg-resolver] WARNING: error resolving fuchsia-pkg://fuchsia.com/intl_property_manager/0 ...

Restart and reboot your device

(Optional) If developing with the emulator, launch (or shutdown and relaunch) the emulator.

fx vdl start -N

NOTE: Do not run the default package server. The instructions below describe how to launch a flutter-specific package server.

Or if you've rebuilt fuchsia for a device that is already running a version of fuchsia, you may be able to reboot without restarting the device:

$ fx reboot -r

If you are building a device that launches the UI at startup, you will likely need to kill Scenic before running the test.

$ fx shell killall scenic.cmx

Build the test

You can specify the test's package target to build only the test package, with its dependencies. This will also build the required runner.

$ cd "$FLUTTER_ENGINE_DIR/src"
$ ./flutter/tools/gn --fuchsia <flags> \
      # for example: --goma --fuchsia-cpu=x64 --runtime-mode=debug
$ ninja -C out/fuchsia_debug_x64 \
    flutter/shell/platform/fuchsia/flutter/integration_flutter_tests

Publish the test packages to the Fuchsia package server

The tests currently specify the Fuchsia package server's standard domain, fuchsia.com, as the server to use to resolve (locate and load) the test packages. So, before running the test, the most recently built .far files need to be published to the Fuchsia package repo:

$ fx pm publish -a -repo "$(cat $FUCHSIA_DIR/.fx-build-dir)/amber-files/" \
  -f "$FLUTTER_ENGINE_DIR"/src/out/fuchsia_*64/flutter-embedder-test2-0.far
$ fx pm publish -a -repo "$(cat $FUCHSIA_DIR/.fx-build-dir)/amber-files/" \
  -f $(find "$FLUTTER_ENGINE_DIR"/src/out/fuchsia_*64 -name parent-view2.far)
$ fx pm publish -a -repo "$(cat $FUCHSIA_DIR/.fx-build-dir)/amber-files/" \
  -f $(find "$FLUTTER_ENGINE_DIR"/src/out/fuchsia_*64 -name child-view2.far)

Run the test (using the package server at fuchsia.com)

$ fx shell run-test-component \
    fuchsia-pkg://fuchsia.com/flutter-embedder-test2#meta/flutter-embedder-test2.cmx

Make a change and re-run the test

If, for example, you only make a change to the Dart code in parent-view2, you can rebuild only the parent-view2 package target, republish it, and then re-run the test, with:

$ ninja -C out/fuchsia_debug_x64 \
    flutter/shell/platform/fuchsia/flutter/integration_flutter_tests/embedder/parent-view2:package
$ fx pm publish -a -repo "$(cat $FUCHSIA_DIR/.fx-build-dir)/amber-files/" \
  -f $(find "$FLUTTER_ENGINE_DIR"/src/out/fuchsia_*64 -name parent-view2.far)
$ fx shell run-test-component \
    fuchsia-pkg://fuchsia.com/flutter-embedder-test2#meta/flutter-embedder-test2.cmx

From here, you can modify the Flutter test, rebuild flutter, and usually rerun the test without rebooting, by repeating the commands above.

The embedder tests must be run on a product without a graphical base shell, such as core because it starts and stops Scenic.

(Alternative) Serving flutter packages from a custom package server

If you want to use a custom package server, you will need to edit these sources:

* `//flutter/shell/platform/fuchsia/flutter/integration_flutter_tests/embedder/flutter-embedder-test2.cc`
* `//flutter/shell/platform/fuchsia/flutter/integration_flutter_tests/embedder/parent-view2/parent_view2.dart`

Search for the component URLs with fuchsia.com, and change it to engine, which is the domain currently registered with the custom package server in //tools/fuchsia/devshell/serve.sh.

WARNING: Be careful not to check in that change because CI requires using the fuchsia.com domain/package server.

The default fuchsia package server (launched via fx serve) is normally required, unless all of your test's package dependencies are included in the fuchsia system image. You can force additional packages into the system image with fx set ... --with-base <package> (instead of using --with). For example, in the fx set command above, using, --with-base scenic, and so on. Note, however, that the default core.x64 configuration bundles the test runner as if it was included via --with //garnet/packages/testing:run_test_component, so to include the test runner in the system image requires adding that package as well, via --with-base, instead.

In order to serve fuchsia package dependencies (like run_test_component, scenic, root_presenter, and hardware-display-controller-provider), without forcing them into the system image, you will need to run the fuchsia default package server, via fx serve.

The flutter/engine packages (tests and flutter runners, for dart-based tests) are served from a separate package server. The flutter/engine repo‘s serve.sh script launches this secondary package server, and configures package URL rewrite rules to redirect fuchsia’s requests for flutter- and dart-runner packages from fuchsia.com to flutter's package server instead.

IMPORTANT: The flutter package server must be launched after the default package server, because both fx serve and flutter's serve.sh set package URL rewrite rules, and only the last one wins.

Launch each package server in a separate window or shell:

$ cd "${FUCHSIA_DIR}"
$ fx serve

From the flutter engine src directory, run the following script to launch the engine package server, to serve the flutter runner and test components.

$ flutter/tools/fuchsia/devshell/serve.sh --out out/fuchsia_debug_x64 --only-serve-runners

Run the test, using engine as the package server domain

$ fx shell run-test-component \
    fuchsia-pkg://engine/flutter-embedder-test2#meta/flutter-embedder-test2.cmx

You can recompile and run the test without needing to re-publish the .far.