Added Jest/testing support

.babelrc

@@ -0,0 +1,3 @@
+{
+  "presets": ["next/babel"]
+}

.eslintrc.json

@@ -2,12 +2,14 @@
   "env": {
     "browser": true,
     "es2021": true,
+    "jest": true,
     "node": true
   },
   "extends": [
     "airbnb",
     "eslint:recommended",
     "plugin:@typescript-eslint/recommended",
+    "plugin:jest/recommended",
     "plugin:react/recommended",
     "prettier"
   ],
@@ -22,7 +24,7 @@
     "ecmaVersion": 12,
     "sourceType": "module"
   },
-  "plugins": ["@typescript-eslint", "react", "simple-import-sort"],
+  "plugins": ["@typescript-eslint", "jest", "react", "simple-import-sort"],
   "rules": {
     "max-lines": ["error", 80],
     "react/jsx-filename-extension": [1, { "extensions": [".tsx"] }],

__tests__/pages/index.spec.tsx

@@ -0,0 +1,9 @@
+import { render } from '@testing-library/react';
+import Index from 'pages/index';
+
+test('renders index page', () => {
+  const { getByText } = render(<Index />);
+  const helloWorldElement = getByText('Hello, world!');
+
+  expect(helloWorldElement).toBeInTheDocument();
+});

jest.config.js

@@ -0,0 +1,4 @@
+module.exports = {
+  moduleDirectories: ['.', 'node_modules'],
+  setupFilesAfterEnv: ['<rootDir>/jest.setup.js']
+};

jest.setup.js

@@ -0,0 +1 @@
+import '@testing-library/jest-dom/extend-expect';

package.json

@@ -9,7 +9,8 @@
     "eslint": "eslint .",
     "stylelint": "stylelint **/*.scss",
     "prettier": "prettier --write .",
-    "test": "echo \"Error: no test specified\" && exit 1"
+    "test": "jest",
+    "test:watch": "jest --watch"
   },
   "repository": {
     "type": "git",
@@ -24,6 +25,9 @@
     "sass": "^1.32.2"
   },
   "devDependencies": {
+    "@testing-library/jest-dom": "^5.11.8",
+    "@testing-library/react": "^11.2.3",
+    "@types/jest": "^26.0.20",
     "@types/node": "^14.14.20",
     "@types/react": "^17.0.0",
     "@typescript-eslint/eslint-plugin": "^4.12.0",
@@ -33,11 +37,13 @@
     "eslint-config-prettier": "^7.1.0",
     "eslint-import-resolver-typescript": "^2.3.0",
     "eslint-plugin-import": "^2.22.1",
+    "eslint-plugin-jest": "^24.1.3",
     "eslint-plugin-jsx-a11y": "^6.4.1",
     "eslint-plugin-react": "^7.22.0",
     "eslint-plugin-react-hooks": "^4.2.0",
     "eslint-plugin-simple-import-sort": "^7.0.0",
     "husky": "^4.3.7",
+    "jest": "^26.6.3",
     "lint-staged": "^10.5.3",
     "prettier": "2.2.1",
     "stylelint": "^13.8.0",