feat: Make Jest unit tests run faster in GitHub actions

.github/workflows/run-unit-tests.yml

@@ -1,32 +1,52 @@
-# WARNING! It is currently being investigated how to make this faster
-# DO NOT blindly copy this workflow, not noticing the slow down,
-# because suddenly our tests will take hours to pass CI.
-# Hopefully this comment here will help prevent that.
-# https://github.com/MetaMask/metamask-extension/issues/25680
-
 name: Run unit tests
 
 on:
+  push:
+    branches: [develop, master]
   pull_request:
     types: [opened,reopened,synchronize]
 
 jobs:
-  test-unit-jest:
+  test-unit:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        shard: [1, 2, 3, 4, 5, 6, 7, 8]
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
 
       - name: Setup environment
         uses: ./.github/actions/setup-environment
 
-      - name: test:coverage:jest:dev
-        run: yarn test:coverage:jest:dev
+      - name: test:unit:coverage
+        run: yarn test:unit:coverage --shard=${{ matrix.shard }}/${{ strategy.job-total }}
+
+      - name: Rename coverage to shard coverage
+        run: mv coverage/coverage-final.json coverage/coverage-${{matrix.shard}}.json
+
+      - uses: actions/upload-artifact@v4
+        with:
+          name: coverage-${{matrix.shard}}
+          path: coverage/coverage-${{matrix.shard}}.json
+
+  report-coverage:
+    runs-on: ubuntu-latest
+    needs:
+      - test-unit
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
 
-      - name: test:coverage:jest
-        run: yarn test:coverage:jest
+      - name: Download coverage from shards
+        uses: actions/download-artifact@v4
+        with:
+          path: coverage
+          pattern: coverage-*
+          merge-multiple: true
 
-      - uses: codecov/codecov-action@e28ff129e5465c2c0dcc6f003fc735cb6ae0c673
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@e28ff129e5465c2c0dcc6f003fc735cb6ae0c673
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: true

development/build/transforms/remove-fenced-code.test.js

@@ -36,6 +36,10 @@ describe('build/transforms/remove-fenced-code', () => {
       lintTransformedFileMock.mockImplementation(() => Promise.resolve());
     });
 
+    afterEach(() => {
+      jest.resetAllMocks();
+    });
+
     it('returns a PassThrough stream for files with ignored extensions', async () => {
       const fileContent = '"Valid JSON content"\n';
       const stream = createRemoveFencedCodeTransform(

jest.config.js

@@ -1,12 +1,7 @@
 module.exports = {
-  collectCoverageFrom: [
-    '<rootDir>/app/scripts/**/*.(js|ts|tsx)',
-    '<rootDir>/shared/**/*.(js|ts|tsx)',
-    '<rootDir>/ui/**/*.(js|ts|tsx)',
-  ],
   coverageDirectory: './coverage',
   coveragePathIgnorePatterns: ['.stories.*', '.snap'],
-  coverageReporters: ['html', 'json'],
+  coverageReporters: ['json'],
   reporters: [
     'default',
     [
@@ -28,6 +23,7 @@ module.exports = {
     '<rootDir>/ui/**/*.test.(js|ts|tsx)',
     '<rootDir>/development/fitness-functions/**/*.test.(js|ts|tsx)',
     '<rootDir>/test/e2e/helpers.test.js',
+    '<rootDir>/development/build/transforms/**/*.test.(js|ts|tsx)',
   ],
   testTimeout: 5500,
   // We have to specify the environment we are running in, which is jsdom. The

package.json

@@ -38,12 +38,12 @@
     "dapp-chain": "GANACHE_ARGS='-b 2' concurrently -k -n ganache,dapp -p '[{time}][{name}]' 'yarn ganache:start' 'sleep 5 && yarn dapp'",
     "forwarder": "node ./development/static-server.js ./node_modules/@metamask/forwarder/dist/ --port 9010",
     "dapp-forwarder": "concurrently -k -n forwarder,dapp -p '[{time}][{name}]' 'yarn forwarder' 'yarn dapp'",
+    "test:unit": "jest",
+    "test:unit:watch": "jest --watch",
+    "test:unit:global": "mocha test/unit-global/*.test.js",
+    "test:unit:coverage": "jest --coverage",
     "test:integration": "jest --config jest.integration.config.js",
     "test:integration:coverage": "jest --config jest.integration.config.js --coverage",
-    "test:unit": "node ./test/run-unit-tests.js --jestGlobal --jestDev",
-    "test:unit:jest": "node ./test/run-unit-tests.js --jestGlobal --jestDev",
-    "test:unit:jest:watch": "node --inspect ./node_modules/.bin/jest --watch",
-    "test:unit:global": "mocha test/unit-global/*.test.js",
     "test:e2e:chrome": "SELENIUM_BROWSER=chrome node test/e2e/run-all.js",
     "test:e2e:chrome:mmi": "SELENIUM_BROWSER=chrome node test/e2e/run-all.js --mmi",
     "test:e2e:chrome:flask": "SELENIUM_BROWSER=chrome node test/e2e/run-all.js --build-type flask",
@@ -61,10 +61,6 @@
     "test:e2e:firefox": "SELENIUM_BROWSER=firefox node test/e2e/run-all.js",
     "test:e2e:firefox:flask": "SELENIUM_BROWSER=firefox node test/e2e/run-all.js --build-type flask",
     "test:e2e:single": "node test/e2e/run-e2e-test.js",
-    "test:coverage:jest": "node ./test/run-unit-tests.js --jestGlobal --coverage",
-    "test:coverage:jest:dev": "node ./test/run-unit-tests.js --jestDev --coverage",
-    "test:coverage": "node ./test/run-unit-tests.js --jestGlobal --jestDev --coverage",
-    "test:coverage:html": "yarn test:coverage --html",
     "ganache:start": "./development/run-ganache.sh",
     "sentry:publish": "node ./development/sentry-publish.js",
     "lint": "yarn lint:prettier && yarn lint:eslint && yarn lint:tsc && yarn lint:styles",