Fix Jest inline snapshots

[jeremywiebe]

Summary:

While writing some tests, I wanted to use inline snapshots, but Jest complained that inline snapshots aren't supported on Prettier v3 (which we use).

The solution is to install Prettier v2 beside v3 and customize Jest to use v2.

Support for Prettier v3 has already landed and will be in Jest 30 but the last I saw was an issue comment from Oct 2023 and even then the author was unsure when it would be released. I'll just use the workaround for now.

Issue: "none"

Test plan:

Find a test that uses .toMatchInlineSnapshot() and delete the snapshot string passed to the function.
Save the file
yarn test
Note that the snapshot string is back!

Screen.Recording.2024-12-05.at.7.34.53.PM.mov

[github-actions]

npm Snapshot: Published

Good news!! We've packaged up the latest commit from this PR (81fd4cd) and published it to npm. You
can install it using the tag PR1963.

Example:

yarn add @khanacademy/perseus@PR1963

If you are working in Khan Academy's webapp, you can run:

./dev/tools/bump_perseus_version.sh -t PR1963

[github-actions]

Size Change: 0 B

Total Size: 1.29 MB

ℹ️ View Unchanged

Filename	Size
packages/kas/dist/es/index.js	39 kB
packages/keypad-context/dist/es/index.js	760 B
packages/kmath/dist/es/index.js	4.27 kB
packages/math-input/dist/es/index.js	77.9 kB
packages/math-input/dist/es/strings.js	1.79 kB
packages/perseus-core/dist/es/index.js	1.48 kB
packages/perseus-editor/dist/es/index.js	697 kB
packages/perseus-linter/dist/es/index.js	22.2 kB
packages/perseus/dist/es/index.js	425 kB
packages/perseus/dist/es/strings.js	3.7 kB
packages/pure-markdown/dist/es/index.js	3.66 kB
packages/simple-markdown/dist/es/index.js	12.5 kB

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[khan-actions-bot]

Gerald

Required Reviewers

• @Khan/perseus for changes to package.json, yarn.lock, config/test/test.config.js

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[jeremywiebe]

Closing. This doesn't work as the prettier-2 instance gets installed in node_modules/.bin which then causes formatting issues when we check formatting with yarn prettier --check in GitHub Actions.

Abandoning for now. Wait for Jest v30. 😓