Hacking on Sky

Building

• Follow the setup & build instructions for Mojo

If building for Android, be aware a patch to V8's GN build is required: https://code.google.com/p/v8/issues/detail?id=3841

Running applications

• ./sky/tools/skydb start out/Debug [url]

  skydb has numerous commands, visible via skydb help. Common ones include:

  • skybd start BUILD_DIR [url]
  • skydb load [url]
  • skydb stop
  • skydb print_crash # Symbolicate the most recent crash from android.

Once skydb start is issued, all subsequent commands will be sent to the running mojo_shell instance (even on an attached android device). skydb start reads gn args from the passed build directory to determine whether its using android, etc.

• ./sky/tools/test_sky --debug
  • This runs the tests against //out/Debug. If you want to run against //out/Release, omit the --debug flag.

Running tests manually

• sky/tools/run_sky_httpd
• out/Debug/mojo_shell --args-for="mojo:native_viewport_service --use-headless-config" --content-handlers=text/html,mojo:sky_viewer --url-mappings=mojo:window_manager=mojo:sky_tester mojo:window_manager
• The sky_tester should print #READY when ready
• Type the URL you wish to run, for example http://127.0.0.1:8000/lowlevel/text.html, and press the enter key
• The harness should print the results of the test. You can then type another URL.

Writing tests

• Import resources/mocha.html and resources/chai.html
• Write tests in mocha format and use chai asserts:

describe('My pretty test of my subject', function() {
  var subject = new MySubject();

  it('should be pretty', function() {
    assert.ok(subject.isPretty);
  });
});

Adding pixel tests

Sky does not have proper pixel tests. Instead we have only reftests. If you want a pixel test, you need to dump the png from a reftest, upload it to googlestorage and then put and pointing to the uploaded file in the reference.

1. Create your test (e.g. foo.sky).
2. Create an dummy reference file (foo-expected.sky).
3. Run the test (it will fail).
4. Copy the -actual.png file to googlestorage (see below).
5. Put an <img> pointing to your newly uploaded png in the reference file at http://storage.googleapis.com/mojo/sky-pngs/SHA1_HASH_HERE

Copying the file to googlestorage:

$ sha1sum ../out/Debug/layout-test-results/framework/flights-app-pixels-actual.png
db0508cdfe69e996a93464050dc383f6480f1283  ../out/Debug/layout-test-results/framework/flights-app-pixels-actual.png
$ gsutil.py cp ../out/Debug/layout-test-results/framework/flights-app-pixels-actual.png gs://mojo/sky-pngs/db0508cdfe69e996a93464050dc383f6480f1283

Long-term, we should not have these tests at all and should just dump paint commands. In the short-term, if we find we're doing this a lot we should obviously automate this process, e.g. test_sky could do all of this work, including spitting out the correct reference file.