Unit tests

- added dev dependencies on `jest`, `nock` and `eslint-plugin-jest`
- added test cases for class `CallbackUriNotifier`
- added GitHub Action

.eslintrc.json

@@ -2,7 +2,8 @@
   "env": {
     "node": true,
     "es6": true,
-    "browser": true
+    "browser": true,
+    "jest/globals": true
   },
   "extends": "eslint:recommended",
   "overrides": [],
@@ -15,6 +16,12 @@
     "comma-dangle": ["error", "always-multiline"],
     "comma-spacing": ["error", { "before": false, "after": true }],
     "no-trailing-spaces": "error",
-    "eol-last": ["error", "always"]
-  }
+    "eol-last": ["error", "always"],
+    "jest/no-disabled-tests": "warn",
+    "jest/no-focused-tests": "error",
+    "jest/no-identical-title": "error",
+    "jest/prefer-to-have-length": "warn",
+    "jest/valid-expect": "error"
+  },
+  "plugins": ["jest"]
 }

.github/workflows/tests.yml

@@ -0,0 +1,34 @@
+name: Tests
+
+on:
+  push:
+    branches:
+      - main
+    tags:
+      - v*
+  pull_request:
+    branches:
+      - main
+
+env:
+  PUPPETEER_SKIP_DOWNLOAD: true
+  PUPPETEER_SKIP_CHROMIUM_DOWNLOAD: true
+
+jobs:
+  unit:
+    name: Unit tests
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Setup node
+        uses: actions/setup-node@v3
+        with:
+          node-version: 20
+
+      - name: Install dependencies
+        run: npm install
+
+      - name: Jest
+        run: npm test