Ignore error when axe core fails to inject into blank iframes

[talldan]

Description

Previously #26527, #26535

Axe core tests fail intermittently:

Template Part › Template part placeholder › Should insert template part when preview is selected

    expect(jest.fn()).not.toHaveErrored(expected)

    Expected mock function not to be called but it was called with:
    ["Failed to inject axe-core into frame (about:blank)"],["Failed to inject axe-core into frame (about:blank)"]

This occurs when axe attempts to inject scripts into iframes created by the react-resize-aware utility in the useResizeObserver hook, mostly when tests briefly interact with block previews.

This PR adds the error message to our list of exceptions for things that will fail tests.

Axe itself won't fail tests when this injection fails, so it seems we're being stricter than Axe:
https://github.com/dequelabs/axe-core-npm/blob/1f06cb67e2bbbf1922fd9d2e6bcee74f092cfa1c/packages/puppeteer/src/axePuppeteer.ts#L67-L69

How has this been tested?

CI tests should regularly pass.

[github-actions]

Size Change: +208 B (0%)

Total Size: 1.21 MB

Filename	Size	Change
build/block-editor/index.js	130 kB	+207 B (0%)
build/block-library/index.js	146 kB	+20 B (0%)
build/components/index.js	172 kB	+30 B (0%)
build/components/style-rtl.css	15.2 kB	+2 B (0%)
build/components/style.css	15.2 kB	+3 B (0%)
build/compose/index.js	9.81 kB	-1 B
build/data/index.js	8.77 kB	-2 B (0%)
build/edit-site/index.js	22.1 kB	-50 B (0%)
build/editor/index.js	43.1 kB	-1 B
build/element/index.js	4.65 kB	-1 B
build/list-reusable-blocks/index.js	3.11 kB	+1 B
build/media-utils/index.js	5.34 kB	+1 B
build/nux/index.js	3.42 kB	+1 B
build/rich-text/index.js	13.2 kB	-1 B
build/server-side-render/index.js	2.77 kB	-1 B

ℹ️ View Unchanged

Filename	Size	Change
build/a11y/index.js	1.14 kB	0 B
build/annotations/index.js	3.78 kB	0 B
build/api-fetch/index.js	3.45 kB	0 B
build/autop/index.js	2.84 kB	0 B
build/blob/index.js	665 B	0 B
build/block-directory/index.js	8.72 kB	0 B
build/block-directory/style-rtl.css	943 B	0 B
build/block-directory/style.css	942 B	0 B
build/block-editor/style-rtl.css	11.1 kB	0 B
build/block-editor/style.css	11.1 kB	0 B
build/block-library/editor-rtl.css	8.97 kB	0 B
build/block-library/editor.css	8.97 kB	0 B
build/block-library/style-rtl.css	7.83 kB	0 B
build/block-library/style.css	7.84 kB	0 B
build/block-library/theme-rtl.css	837 B	0 B
build/block-library/theme.css	838 B	0 B
build/block-serialization-default-parser/index.js	1.88 kB	0 B
build/block-serialization-spec-parser/index.js	3.1 kB	0 B
build/blocks/index.js	48.1 kB	0 B
build/core-data/index.js	12.3 kB	0 B
build/data-controls/index.js	772 B	0 B
build/date/index.js	31.8 kB	0 B
build/deprecated/index.js	768 B	0 B
build/dom-ready/index.js	571 B	0 B
build/dom/index.js	4.46 kB	0 B
build/edit-navigation/index.js	11.2 kB	0 B
build/edit-navigation/style-rtl.css	881 B	0 B
build/edit-navigation/style.css	885 B	0 B
build/edit-post/index.js	306 kB	0 B
build/edit-post/style-rtl.css	6.4 kB	0 B
build/edit-post/style.css	6.39 kB	0 B
build/edit-site/style-rtl.css	3.88 kB	0 B
build/edit-site/style.css	3.88 kB	0 B
build/edit-widgets/index.js	26.4 kB	0 B
build/edit-widgets/style-rtl.css	3.12 kB	0 B
build/edit-widgets/style.css	3.12 kB	0 B
build/editor/editor-styles-rtl.css	480 B	0 B
build/editor/editor-styles.css	482 B	0 B
build/editor/style-rtl.css	3.85 kB	0 B
build/editor/style.css	3.85 kB	0 B
build/escape-html/index.js	735 B	0 B
build/format-library/index.js	7.7 kB	0 B
build/format-library/style-rtl.css	547 B	0 B
build/format-library/style.css	548 B	0 B
build/hooks/index.js	2.13 kB	0 B
build/html-entities/index.js	623 B	0 B
build/i18n/index.js	3.57 kB	0 B
build/is-shallow-equal/index.js	712 B	0 B
build/keyboard-shortcuts/index.js	2.52 kB	0 B
build/keycodes/index.js	1.94 kB	0 B
build/list-reusable-blocks/style-rtl.css	476 B	0 B
build/list-reusable-blocks/style.css	476 B	0 B
build/notices/index.js	1.79 kB	0 B
build/nux/style-rtl.css	671 B	0 B
build/nux/style.css	668 B	0 B
build/plugins/index.js	2.56 kB	0 B
build/primitives/index.js	1.43 kB	0 B
build/priority-queue/index.js	791 B	0 B
build/redux-routine/index.js	2.85 kB	0 B
build/reusable-blocks/index.js	3.06 kB	0 B
build/shortcode/index.js	1.69 kB	0 B
build/token-list/index.js	1.27 kB	0 B
build/url/index.js	4.06 kB	0 B
build/viewport/index.js	1.84 kB	0 B
build/warning/index.js	1.14 kB	0 B
build/wordcount/index.js	1.22 kB	0 B

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[Addison-Stavlo]

Wow! A bit disappointing and surprising that the approach in #26535 didn't work out.

Axe itself won't fail tests when this injection fails, so it seems we're being stricter than Axe

Interesting! It seems to make sense to not fail our tests as a result of this axe error. Especially since all other approaches seem to not work out. Il re-run the tests a few times and see if its consistent.

[Addison-Stavlo]

🤦‍♀️ - It seems to still fail on the error... 🤷‍♀️

Expected mock function not to be called but it was called with:
    ["Failed to inject axe-core into frame (about:blank)"],["Failed to inject axe-core into frame (about:blank)"]

[talldan]

@Addison-Stavlo 🤔 I'm guessing text is an array of arrays or something given the output.

[talldan]

Nope, that didn't work either.

I think I have to call it quits there. I've spent quite a bit of my time looking into these issues. It's about time that others on the project stepped up and helped.