Add unit tests

.github/workflows/nodejs-ci.yml

@@ -0,0 +1,37 @@
+name: Node.js CI
+on:
+  pull_request:
+    branches: [ "master" ]
+  push:
+
+jobs:
+
+  test:
+
+    runs-on: ubuntu-latest
+
+    env:
+      YARN_IGNORE_NODE: 1
+
+    strategy:
+      matrix:
+        node-version: [18.x, 20.x, 22.x]
+
+    steps:
+
+      - name: 'Checkout the repository'
+        uses: actions/checkout@v4
+
+      - name: Test with Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+
+      - name: Install dependencies
+        run: npm install
+
+      - name: Compile TypeScript test code
+        run: npm run compile-test
+
+      - name: Run tests
+        run: npm run test

.mocharc.json

@@ -0,0 +1,3 @@
+{
+  "spec": ["test/*.js"]
+}

package.json

@@ -3,6 +3,14 @@
   "version": "1.0.0",
   "main": "index.js",
   "types": "index.d.ts",
+  "scripts": {
+    "test": "mocha",
+    "compile-test": "tsc -p test"
+  },
+  "files": [
+    "index.js",
+    "index.d.ts"
+  ],
   "author": {
     "name": "Borewit",
     "url": "https://github.com/Borewit"
@@ -45,5 +53,12 @@
   "engines": {
     "node": ">=13.2.0"
   },
-  "dependencies": {}
+  "devDependencies": {
+    "@types/chai": "^5.0.1",
+    "@types/mocha": "^10.0.10",
+    "@types/node": "^22.10.2",
+    "chai": "^4.3.4",
+    "mocha": "^11.0.1",
+    "typescript": "^5.7.2"
+  }
 }

test/mock.mjs

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+export const testValue = 42;

test/test.ts

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+import {describe, it} from 'mocha';
+import * as chai from 'chai';
+import * as path from 'path';
+import {loadEsm} from '../index.js';
+
+const {expect} = chai;
+
+describe('loadEsm', function () {
+  it('should load an ES module dynamically', async function () {
+    // Mock ES module file for testing.
+    const modulePath = path.join(__dirname, 'mock.mjs');
+
+    // Load the ES module dynamically using loadEsm.
+    const esmModule = await loadEsm(`file://${modulePath}`);
+
+    // Verify the loaded module.
+    expect(esmModule).to.be.an('module');
+    expect(esmModule.testValue).to.equal(42);
+  });
+
+  it('should throw an error if the module path is invalid', async function () {
+    const invalidPath = 'file:///non-existent-module.js';
+
+    try {
+      await loadEsm(invalidPath);
+      // If no error is thrown, this test should fail.
+      throw new Error('Expected loadEsm to throw an error, but it did not.');
+    } catch (error) {
+      // Verify that the error is thrown.
+      expect(error).to.be.an('error');
+    }
+  });
+});

test/tsconfig.json

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+{
+  "compilerOptions": {
+    "inlineSources": false,
+    "module": "commonjs",
+    "moduleResolution": "node",
+    "target": "ES2017"
+  }
+}