refactor: migrate to node:test and setup jsdom environment

.github/workflows/nodejs.yml

@@ -64,19 +64,18 @@ jobs:
         run: npx commitlint --from ${{ github.event.pull_request.head.sha }}~${{ github.event.pull_request.commits }} --to ${{ github.event.pull_request.head.sha }} --verbose
 
   test:
-    name: Test - ${{ matrix.os }} - Node v${{ matrix.node-version }}, Webpack ${{ matrix.webpack-version }} (${{ matrix.shard }})
+    name: Test - ${{ matrix.os }} - Node v${{ matrix.node-version }}, Webpack ${{ matrix.webpack-version }}
 
     strategy:
       matrix:
         os: [ubuntu-latest, windows-latest, macos-latest]
         node-version: [22.x, 24.x, 25.x]
-        shard: ["1/4", "2/4", "3/4", "4/4"]
         webpack-version: [latest]
 
     runs-on: ${{ matrix.os }}
 
     concurrency:
-      group: test-${{ matrix.os }}-v${{ matrix.node-version }}-${{ matrix.webpack-version }}-${{ matrix.shard }}-${{ github.ref }}
+      group: test-${{ matrix.os }}-v${{ matrix.node-version }}-${{ matrix.webpack-version }}-${{ github.ref }}
       cancel-in-progress: true
 
     steps:
@@ -106,7 +105,7 @@ jobs:
           cp -R tmp-client client
 
       - name: Run tests for webpack version ${{ matrix.webpack-version }}
-        run: npm run test:coverage -- --ci --shard=${{ matrix.shard }}
+        run: npm run test:coverage
 
       - name: Submit coverage data to codecov
         uses: codecov/codecov-action@v5

.gitignore

@@ -5,6 +5,7 @@ npm-debug.log
 .idea
 
 client
+tmp-client
 !/examples/client
 !/test/client
 coverage

eslint.config.mjs

@@ -3,7 +3,7 @@ import config from "eslint-config-webpack";
 import configs from "eslint-config-webpack/configs.js";
 
 export default defineConfig([
-  globalIgnores(["client/**/*", "examples/**/*"]),
+  globalIgnores(["client/**/*", "tmp-client/**/*", "examples/**/*"]),
   {
     extends: [config],
     ignores: ["client-src/**/*", "!client-src/webpack.config.js"],
@@ -21,5 +21,45 @@ export default defineConfig([
   {
     files: ["test/**/*"],
     extends: [configs["universal-recommended"]],
+    languageOptions: {
+      globals: {
+        // Injected via `node --import scripts/setupTest.js`.
+        describe: "readonly",
+        suite: "readonly",
+        it: "readonly",
+        test: "readonly",
+        before: "readonly",
+        after: "readonly",
+        beforeAll: "readonly",
+        afterAll: "readonly",
+        beforeEach: "readonly",
+        afterEach: "readonly",
+        expect: "readonly",
+        jest: "readonly",
+      },
+    },
+    rules: {
+      // Tests are internal; we don't want JSDoc on every helper function.
+      "jsdoc/require-jsdoc": "off",
+      "jsdoc/require-param-type": "off",
+      "jsdoc/require-param-description": "off",
+      "jsdoc/require-returns": "off",
+      "jsdoc/no-blank-blocks": "off",
+      // Debug logs and short reducer args are common in test code.
+      "no-console": "off",
+      "id-length": "off",
+    },
+  },
+  {
+    files: ["test/helpers/**/*", "scripts/setupTest.js"],
+    rules: {
+      // The compat helpers wrap third-party APIs and intentionally use
+      // experimental Node features behind documented flags.
+      "jsdoc/require-param-type": "off",
+      "jsdoc/require-param-description": "off",
+      "jsdoc/require-returns": "off",
+      "jsdoc/no-blank-blocks": "off",
+      "n/no-unsupported-features/node-builtins": "off",
+    },
   },
 ]);