PSA: explicitly listing data dependency for blink_web_tests

[Weizhong Xia]

Dear blink devs

As of now blink_web_tests has a data dependency on //third_party/blink/web_tests. I made a CL that listed the next level directories as the data dependency for blink_web_tests. By doing this, we can skip some baselines for some platforms. For example, we never use linux baselines on Windows.

Even though the sub directories under web_tests are pretty stable nowadays, we added a presubmit check to make sure all the test directories are listed in //BUILD.gn.  If it happens you need to add a new directory under web_tests, please also update //BUILD.gn to list the new folder under the mark "# === List Test Cases folders here ===". Otherwise, the presubmit check will give a warning for that.

In this CL we also assumed flag-specific tests only run on linux-bots. Pls speak up if you know this is not the case. A note is added to //docs/testing/web_tests.md, and if you need to run flag-specific tests on some other platforms in future, please remember to update //BUILD.gn also.

thanks, Weizhong

[Stefan Zager]

On Tue, Sep 7, 2021 at 9:01 AM 'Weizhong Xia' via blink-dev <blin...@chromium.org> wrote:

In this CL we also assumed flag-specific tests only run on linux-bots. Pls speak up if you know this is not the case.

I don't think that's true. Virtual test suites run on all platforms, and they rely on expectation files in flag-specific/.

[Weizhong Xia]

I did search the source code before I made the change. Seems the os type is always ubuntu for flag-specific builders. And CQ dry run can actually pass. I would imagine the test will fail if we are missing so many test expectations.

Virtual tests are different to flag-specific tests, right?