Web tests fail due to crashing tabs while checking for style guide conformance check

[michael-kerscher]

The WebDriver has issues due to tabs crashing while checking slides for conformance with the style guide.

It seems like this is failing mostly in (because of with method "POST" and args "{"using":"css selector","value":"#content > main"}"

comprehensive-rust/tests/src/objects/slide.ts

Lines 23 to 25 in 17a0407

	get main_content() {
	return $("#content > main");
	}

I'm not sure on why this happens. A quick mitigation could be to disable the test entirely. Another mitigation option is to only check files that have been changed in the PR at all. The last one should not be too difficult and has a better efficiency and speeds up the checks massively!

This is visible in runs like https://github.com/google/comprehensive-rust/actions/runs/18159303020/job/51777458019

Run ./src/slides/create-slide.list.sh
~/work/comprehensive-rust/comprehensive-rust/book/comprehensive-rust-en/html ~/work/comprehensive-rust/comprehensive-rust/tests
~/work/comprehensive-rust/comprehensive-rust/tests
> test
> wdio run ./wdio.conf.ts
Execution of 4 workers started at 2025-10-02T09:02:33.271Z
[0-0] RUNNING in chrome - file:///src/generic-page.test.ts
[0-1] RUNNING in chrome - file:///src/playground.test.ts
[0-3] RUNNING in chrome - file:///src/speaker-notes.test.ts
[0-2] RUNNING in chrome - file:///src/slide-style-guide.test.ts
[0-3] 2025-10-02T09:02:48.800Z WARN webdriver: WebDriverError: element not interactable: [object HTMLButtonElement] has no size and location
[0-3]   (Session info: chrome=140.0.7339.185) when running "actions" with method "POST" and args "{"actions":[{"id":"action1","type":"wheel","parameters":{},"actions":[{"type":"scroll","x":-2531,"y":-15,"deltaX":0,"deltaY":0,"duration":0,"origin":{"element-6066-11e4-a52e-4f735466cecf":"f.AF0A63E12952C6A7284DBF28DCFE6552.d.CEBF99EA81288D278FF1E7AC260C9F05.e.34"}}]}]}"
[0-3] PASSED in chrome - file:///src/speaker-notes.test.ts
[0-0] PASSED in chrome - file:///src/generic-page.test.ts
[0-2] slide concurrency/sync-exercises/link-checker.html is on the exemption list
[0-2] slide concurrency/sync-exercises/solutions.html is on the exemption list
[0-1] PASSED in chrome - file:///src/playground.test.ts
[0-2] slide concurrency/async-exercises/solutions.html is on the exemption list
[0-2] slide concurrency/async-exercises/chat-app.html is on the exemption list
[0-2] slide android/interoperability/java.html is on the exemption list
[0-2] slide android/testing.html is on the exemption list
[0-2] slide bare-metal/aps/entry-point.html is on the exemption list
[0-2] slide bare-metal/aps/aarch64-rt.html is on the exemption list
[0-2] slide exercises/chromium/interoperability-with-cpp.html is on the exemption list
[0-2] slide exercises/chromium/bringing-it-together.html is on the exemption list
[0-2] slide exercises/bare-metal/solutions-morning.html is on the exemption list
[0-2] slide exercises/bare-metal/solutions-afternoon.html is on the exemption list
[0-2] slide exercises/bare-metal/compass.html is on the exemption list
[0-2] slide exercises/bare-metal/rtc.html is on the exemption list
[0-2] 2025-10-02T09:03:42.837Z WARN webdriver: WebDriverError: tab crashed
[0-2]   (Session info: chrome=140.0.7339.185) when running "element" with method "POST" and args "{"using":"css selector","value":"#content > main"}"
[0-2] 2025-10-02T09:03:43.346Z WARN webdriver: WebDriverError: tab crashed
[0-2]   (Session info: chrome=140.0.7339.185) when running "element" with method "POST" and args "{"using":"css selector","value":"#content > main"}"
[0-2] 2025-10-02T09:03:44.352Z WARN webdriver: WebDriverError: tab crashed
[0-2]   (Session info: chrome=140.0.7339.185) when running "element" with method "POST" and args "{"using":"css selector","value":"#content > main"}"
[0-2] 2025-10-02T09:03:44.358Z ERROR webdriver: WebDriverError: tab crashed
[0-2]   (Session info: chrome=140.0.7339.185) when running "element" with method "POST" and args "{"using":"css selector","value":"#content > main"}"
[0-2] tab crashed in "Slide control-flow-basics/loops.html.should not be higher than 1333 pixels or wider than 750 pixels"
tab crashed: WebDriverError: tab crashed
  (Session info: chrome=140.0.7339.185) when running "element" with method "POST" and args "{"using":"css selector","value":"#content > main"}"
    at async Slide.violates_max_size (/home/runner/work/comprehensive-rust/comprehensive-rust/tests/src/objects/slide.ts:39:31)
    at async Context.<anonymous> (/home/runner/work/comprehensive-rust/comprehensive-rust/tests/src/slide-style-guide.test.ts:52:13)
[0-2] 2025-10-02T09:03:44.410Z WARN webdriver: WebDriverError: tab crashed
[0-2]   (Session info: chrome=140.0.7339.185) when running "element" with method "POST" and args "{"using":"css selector","value":"#content > main"}"
[0-2] 2025-10-02T09:03:44.934Z WARN webdriver: WebDriverError: tab crashed
[0-2]   (Session info: chrome=140.0.7339.185) when running "element" with method "POST" and args "{"using":"css selector","value":"#content > main"}"
[0-2] 2025-10-02T09:03:45.941Z WARN webdriver: WebDriverError: tab crashed
[0-2]   (Session info: chrome=140.0.7339.185) when running "element" with method "POST" and args "{"using":"css selector","value":"#content > main"}"
[0-2] 2025-10-02T09:03:45.949Z ERROR webdriver: WebDriverError: tab crashed
[0-2]   (Session info: chrome=140.0.7339.185) when running "element" with method "POST" and args "{"using":"css selector","value":"#content > main"}"
[0-2] tab crashed in "Slide control-flow-basics/if.html.should not be higher than 1333 pixels or wider than 750 pixels"
tab crashed: WebDriverError: tab crashed

[michael-kerscher]

One side note: 483a9ec only tracks changes in the slides. It does not support the usecase of checking mdbook updates.
@mgeisler I think you want to update mdbook IIRC, this is currently untested (or at least, this is recognized once markdown files are changed)

edit: This is not as bad as it sounds like. Generic tests are still executed unconditionally, if a theme change makes slides bigger though, this might slip through the cracks