feat: bump minimum node version to 16 and add tests (#86)

BREAKING CHANGE: Minimum node version is now 16

jest.config.js

@@ -0,0 +1,14 @@
+/** @type {import('ts-jest').JestConfigWithTsJest} */
+module.exports = {
+  preset: 'ts-jest',
+  testEnvironment: 'node',
+  transform: {
+    '.': [
+      'ts-jest',
+      {
+        tsconfig: 'tsconfig.jest.json'
+      }
+    ]
+  },
+  globalSetup: './jest.setup.ts'
+};