[DO NOT MERGE] Trigger CI for #4396: Start migration from jest to vitest

package.json

@@ -18,6 +18,8 @@
         "build:performance:benchmarks": "nx build @lwc/perf-benchmarks",
         "copy-fork": "./scripts/tasks/unsafe-external-contributor-ci-workaround.sh",
         "dev": "nx run-many --target=dev --all --parallel=999 --exclude=@lwc/perf-benchmarks,@lwc/perf-benchmarks-components,@lwc/integration-tests,lwc",
+        "test:vi": "vitest run --workspace vitest.workspace.js",
+        "test:vi:ci": "vitest run --workspace vitest.workspace.js --coverage",
         "test": "jest --config ./scripts/jest/root.config.js",
         "test:bespoke": "nx run-many --target=test",
         "test:debug": "node --inspect node_modules/.bin/jest --config ./scripts/jest/root.config.js --runInBand --watch",
@@ -49,6 +51,8 @@
         "@types/jest": "^29.5.12",
         "@types/node": "^20.14.10",
         "@types/prettier": "^2.7.3",
+        "@vitest/coverage-v8": "^2.0.3",
+        "@vitest/ui": "^2.0.3",
         "bytes": "^3.1.2",
         "es-module-lexer": "^1.5.4",
         "eslint": "^9.7.0",
@@ -71,7 +75,8 @@
         "ts-jest": "^29.2.2",
         "tslib": "^2.6.3",
         "typescript": "5.5.3",
-        "typescript-eslint": "^7.16.1"
+        "typescript-eslint": "^7.16.1",
+        "vitest": "^2.0.3"
     },
     "lint-staged": {
         "*.{js,mjs,ts}": "eslint",

packages/@lwc/babel-plugin-component/vitest.config.js

@@ -0,0 +1,11 @@
+import { defineProject, mergeConfig } from 'vitest/config';
+import baseConfig from '../../../vitest.shared';
+
+export default mergeConfig(
+    baseConfig,
+    defineProject({
+        test: {
+            name: 'babel-plugin-component',
+        },
+    })
+);

packages/@lwc/compiler/src/transformers/__tests__/__snapshots__/transform-html.spec.ts.snap

@@ -0,0 +1,3 @@
+// Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
+
+exports[`transformSync > dynamic components > should not allow dynamic components when experimentalDynamicDirective is set to false > "LWC1128: Invalid lwc:dynamic usage. The LWC dynamic directive must be enabled in order to use this feature." 1`] = `[Error: LWC1128: Invalid lwc:dynamic usage. The LWC dynamic directive must be enabled in order to use this feature.]`;

packages/@lwc/compiler/src/transformers/__tests__/transform-html.spec.ts

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: MIT
  * For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/MIT
  */
+import { vi } from 'vitest';
 import { APIVersion, noop } from '@lwc/shared';
 import { TransformOptions } from '../../options';
 import { transformSync } from '../transformer';
@@ -198,13 +199,13 @@ describe('transformSync', () => {
                     experimentalDynamicDirective: false,
                     ...TRANSFORMATION_OPTIONS,
                 })
-            ).toThrowErrorMatchingInlineSnapshot(
+            ).toThrowErrorMatchingSnapshot(
                 '"LWC1128: Invalid lwc:dynamic usage. The LWC dynamic directive must be enabled in order to use this feature."'
             );
         });
 
         it('gathers metrics around use of the deprecated dynamic components', () => {
-            const incrementCounter = jest.fn();
+            const incrementCounter = vi.fn();
             const template = `
                 <template>
                     <x-dynamic lwc:dynamic={ctor}></x-dynamic>

packages/@lwc/compiler/src/transformers/__tests__/transform-javascript.spec.ts

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: MIT
  * For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/MIT
  */
+import { vi } from 'vitest';
 import { noop } from '@lwc/shared';
 import { TransformOptions } from '../../options';
 import { transform, transformSync } from '../transformer';
@@ -121,7 +122,7 @@ it('should not apply babel plugins when Lightning Web Security is off', async ()
 
 describe('instrumentation', () => {
     it('should gather metrics for transforming dynamic imports', async () => {
-        const incrementCounter = jest.fn();
+        const incrementCounter = vi.fn();
         const actual = `
             export async function test() {
                 const x = await import("foo");

packages/@lwc/compiler/vitest.config.js

@@ -0,0 +1,14 @@
+import { defineProject, mergeConfig } from 'vitest/config';
+import baseConfig from '../../../vitest.shared';
+
+export default mergeConfig(
+    baseConfig,
+    defineProject({
+        test: {
+            name: 'lwc-compiler',
+            alias: {
+                '@lwc/shared': '@lwc/shared/src',
+            },
+        },
+    })
+);

packages/@lwc/engine-core/vitest.config.js

@@ -0,0 +1,11 @@
+import { defineProject, mergeConfig } from 'vitest/config';
+import baseConfig from '../../../vitest.shared';
+
+export default mergeConfig(
+    baseConfig,
+    defineProject({
+        test: {
+            name: 'lwc-engine-core',
+        },
+    })
+);

packages/@lwc/engine-dom/vitest.config.js

@@ -0,0 +1,12 @@
+import { defineProject, mergeConfig } from 'vitest/config';
+import baseConfig from '../../../vitest.shared';
+
+export default mergeConfig(
+    baseConfig,
+    defineProject({
+        test: {
+            name: 'lwc-engine-dom',
+            environment: 'jsdom',
+        },
+    })
+);

packages/@lwc/errors/vitest.config.js

@@ -0,0 +1,11 @@
+import { mergeConfig, defineProject } from 'vitest/config';
+import sharedConfig from '../../../vitest.shared';
+
+export default mergeConfig(
+    sharedConfig,
+    defineProject({
+        test: {
+            name: 'lwc-errors',
+        },
+    })
+);

packages/@lwc/features/src/__tests__/setFeatureFlag.spec.ts

@@ -5,20 +5,21 @@
  * For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/MIT
  */
 
+import { MockInstance, vi } from 'vitest';
 import { lwcRuntimeFlags, setFeatureFlag } from '../index';
 
 describe('setFeatureFlag', () => {
     ['development', 'production'].forEach((env) => {
         describe(`${env} mode`, () => {
             let originalNodeEnv: any;
-            let info: jest.SpyInstance;
-            let error: jest.SpyInstance;
+            let info: MockInstance;
+            let error: MockInstance;
 
             beforeEach(() => {
                 originalNodeEnv = process.env.NODE_ENV;
                 process.env.NODE_ENV = env;
-                info = jest.spyOn(console, 'info').mockImplementation(() => {});
-                error = jest.spyOn(console, 'error').mockImplementation(() => {});
+                info = vi.spyOn(console, 'info').mockImplementation(() => {});
+                error = vi.spyOn(console, 'error').mockImplementation(() => {});
             });
 
             afterEach(() => {

packages/@lwc/features/vitest.config.js

@@ -0,0 +1,11 @@
+import { mergeConfig, defineProject } from 'vitest/config';
+import sharedConfig from '../../../vitest.shared';
+
+export default mergeConfig(
+    sharedConfig,
+    defineProject({
+        test: {
+            name: 'lwc-features',
+        },
+    })
+);

packages/@lwc/rollup-plugin/vitest.config.js

@@ -0,0 +1,14 @@
+import { defineProject, mergeConfig } from 'vitest/config';
+import baseConfig from '../../../vitest.shared';
+
+export default mergeConfig(
+    baseConfig,
+    defineProject({
+        test: {
+            name: 'rollup-plugin-lwc-compiler',
+            alias: {
+                '@lwc/shared': '@lwc/shared/src',
+            },
+        },
+    })
+);

packages/@lwc/shared/vitest.config.js

@@ -0,0 +1,11 @@
+import { defineProject, mergeConfig } from 'vitest/config';
+import baseConfig from '../../../vitest.shared';
+
+export default mergeConfig(
+    baseConfig,
+    defineProject({
+        test: {
+            name: 'lwc-shared',
+        },
+    })
+);

packages/@lwc/signals/src/__tests__/index.spec.ts

@@ -5,6 +5,7 @@
  * For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/MIT
  */
 
+import { vi } from 'vitest';
 import { Signal } from './signal';
 
 describe('signal protocol', () => {
@@ -17,29 +18,29 @@ describe('signal protocol', () => {
         const s = new Signal();
         expect('subscribe' in s).toBe(true);
         expect(typeof s.subscribe).toBe('function');
-        const onUpdate = jest.fn();
+        const onUpdate = vi.fn();
         expect(() => s.subscribe(onUpdate)).not.toThrow();
     });
 
     it('should be able to notify subscribers', () => {
         const s = new Signal();
-        const onUpdate = jest.fn();
+        const onUpdate = vi.fn();
         s.subscribe(onUpdate);
         s.value = 1;
         expect(onUpdate).toHaveBeenCalledTimes(1);
     });
 
     it('subscribe should return an unsubscribe function', () => {
         const s = new Signal();
-        const onUpdate = jest.fn();
+        const onUpdate = vi.fn();
         const unsubscribe = s.subscribe(onUpdate);
         expect(typeof unsubscribe).toBe('function');
     });
 
     it('should not notify once unsubscribed', () => {
         const s = new Signal(0);
-        const onUpdate1 = jest.fn();
-        const onUpdate2 = jest.fn();
+        const onUpdate1 = vi.fn();
+        const onUpdate2 = vi.fn();
         const unsubscribe1 = s.subscribe(onUpdate1);
         const unsubscribe2 = s.subscribe(onUpdate2);
 
@@ -62,7 +63,7 @@ describe('signal protocol', () => {
 
     it('SignalBaseClass does not subscribe duplicate OnUpdate callback functions', () => {
         const s = new Signal(0);
-        const onUpdate = jest.fn();
+        const onUpdate = vi.fn();
         s.subscribe(onUpdate);
         s.subscribe(onUpdate);
 

packages/@lwc/signals/vitest.config.js

@@ -0,0 +1,11 @@
+import { mergeConfig, defineProject } from 'vitest/config';
+import sharedConfig from '../../../vitest.shared';
+
+export default mergeConfig(
+    sharedConfig,
+    defineProject({
+        test: {
+            name: 'lwc-signals',
+        },
+    })
+);

packages/@lwc/style-compiler/vitest.config.js

@@ -0,0 +1,11 @@
+import { mergeConfig, defineProject } from 'vitest/config';
+import sharedConfig from '../../../vitest.shared';
+
+export default mergeConfig(
+    sharedConfig,
+    defineProject({
+        test: {
+            name: 'lwc-style-compiler',
+        },
+    })
+);