Add initial battery of tests

.github/workflows/pull-request.yml

@@ -0,0 +1,23 @@
+name: pull-request
+
+on: pull_request
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    name: Test
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Run tests
+        run: npm test -- --colors

.gitignore

@@ -14,3 +14,6 @@ node_modules
 
 # Build folder
 dist
+
+# Ignore test coverage reports
+coverage

jest.config.js

@@ -0,0 +1,12 @@
+/** @type {import('ts-jest').JestConfigWithTsJest} */
+module.exports = {
+  preset: 'ts-jest',
+  testEnvironment: 'jsdom',
+  testMatch: ['**/__tests__/**/*.test.[jt]s?(x)'],
+  collectCoverageFrom: [
+    'src/**/*.ts',
+    '!src/__tests__/**',
+    '!**/node_modules/**',
+    '!**/coverage/**'
+  ]
+};