refactor(project): remove support for jest (#6452)

Author: joshblack

.github/workflows/ci.yml

@@ -72,12 +72,10 @@ jobs:
         run: npm ci
       - name: Build
         run: npm run build
-      - name: Test
-        run: npm run test -- --coverage
       - name: Run tests defined in vitest
         uses: docker://mcr.microsoft.com/playwright:v1.53.2-jammy
         with:
-          args: npx vitest
+          args: npm test
 
   type-check:
     runs-on: ubuntu-latest

.github/workflows/migration-status.yml

@@ -34,18 +34,3 @@ jobs:
       - name: Run migration script
         run: |
           node --experimental-strip-types script/styled-components-migration-status.mts >> $GITHUB_STEP_SUMMARY
-
-  vitest:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
-      - name: Set up Node.js
-        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020
-        with:
-          node-version: 22
-          cache: 'npm'
-      - name: Install dependencies
-        run: npm ci
-      - name: Run migration script
-        run: |
-          node --experimental-strip-types script/vitest-migration-status.mts >> $GITHUB_STEP_SUMMARY

contributor-docs/CONTRIBUTING.md

@@ -68,7 +68,7 @@ Navigate to http://localhost:6006/ to see Primer react components in your browse
 
 - [React](https://reactjs.org/)
 - [TypeScript](https://www.typescriptlang.org/)
-- [Jest](https://jestjs.io/)
+- [Vitest](https://vitest.dev/)
 - [Storybook](https://storybook.js.org/)
 - [Prettier](https://prettier.io/)
 - [ESLint](https://eslint.org/)

contributor-docs/testing.md

@@ -61,7 +61,7 @@ We make sure that every component has [these fundamental unit tests](https://git
 
 ### Overview
 
-We use [Jest](https://jestjs.io/) as our test runner to write and run our unit tests. Our preferred way of structuring tests is with `describe/it` block format and they are authored within the components's source directory with the file name of `ComponentName.test.tsx`
+We use [Vitest](https://vitest.dev/) as our test runner to write and run our unit tests. Our preferred way of structuring tests is with `describe/it` block format and they are authored within the components's source directory with the file name of `ComponentName.test.tsx`
 
 We predominantly use [@testing-library/react](https://testing-library.com/docs/react-testing-library/intro/)'s testing helpers such as
 
@@ -70,22 +70,20 @@ We predominantly use [@testing-library/react](https://testing-library.com/docs/r
 - `screen`
 - `act`
 
-To make assertions about the elements we use [Jest](https://jestjs.io/) and [jest-dom](https://github.com/testing-library/jest-dom).
+To make assertions about the elements we use [Vitest](https://vitest.dev/) and [jest-dom](https://github.com/testing-library/jest-dom).
 
 \*: Read about the [differences between `fireEvent` and `UserEvent`](https://testing-library.com/docs/user-event/intro/#differences-from-fireevent).
 
 ### Snapshots
 
-We are slowly moving away from using `Jest` snapshots as a way to test visual changes of our components. You can read more about the decision in this [ADR](https://github.com/primer/react/blob/main/contributor-docs/adrs/adr-011-snapshot-tests.md). We are in the process of migrating our existing snapshot tests to use [Playwright](https://playwright.dev/) for visual regression testing. If you are writing a new test and you need to test the visual changes of the component, please refer to the [Visual Regression Tests](#visual-regression-tests) section.
+We are slowly moving away from using snapshots as a way to test visual changes of our components. You can read more about the decision in this [ADR](https://github.com/primer/react/blob/main/contributor-docs/adrs/adr-011-snapshot-tests.md). We are in the process of migrating our existing snapshot tests to use [Playwright](https://playwright.dev/) for visual regression testing. If you are writing a new test and you need to test the visual changes of the component, please refer to the [Visual Regression Tests](#visual-regression-tests) section.
 
 ### Running Tests
 
 | Task                | Command                  |
 | :------------------ | :----------------------- |
 | Run unit tests      | `npm test`               |
 | Run a specific test | `npm test ComponentName` |
-| Debug unit tests    | `npm test -- --watch`    |
-| Unit test coverage  | `npm test -- --coverage` |
 | Update snapshots    | `npm test -- -u`         |
 
 ## Interaction Tests

eslint.config.mjs

@@ -7,7 +7,6 @@ import eslintReact from '@eslint-react/eslint-plugin'
 import vitest from '@vitest/eslint-plugin'
 import {defineConfig, globalIgnores} from 'eslint/config'
 import githubPlugin from 'eslint-plugin-github'
-import jest from 'eslint-plugin-jest'
 import storybook from 'eslint-plugin-storybook'
 import react from 'eslint-plugin-react'
 import reactCompiler from 'eslint-plugin-react-compiler'
@@ -132,7 +131,6 @@ const config = defineConfig([
       globals: {
         ...globals.browser,
         ...globals.commonjs,
-        ...globals.jest,
         ...globals.node,
         __DEV__: 'readonly',
       },
@@ -266,25 +264,6 @@ const config = defineConfig([
       '@eslint-react/no-useless-forward-ref': 'off',
     },
   },
-  // eslint-plugin-jest
-  {
-    files: ['**/*.test.{ts,tsx}'],
-    ignores: ['**/e2e/**'],
-    plugins: {
-      jest,
-      ['testing-library']: testingLibrary,
-    },
-    languageOptions: {
-      globals: jest.environments.globals.globals,
-    },
-    ...jest.configs['flat/recommended'],
-    rules: {
-      ...jest.configs['flat/recommended'].rules,
-      'jest/expect-expect': 'off',
-      'jest/no-conditional-expect': 'off',
-      'jest/no-disabled-tests': 'off',
-    },
-  },
 
   // eslint-plugin-vitest
   {