test: add jest (#14)

- Add jest and some additional core test dependencies
- Add the beginnings of a test, which does nothing at this point other than make jest happy that at least 1 test exists
- Update CI to include tests

.github/workflows/ci.js.yml

@@ -21,10 +21,12 @@ jobs:
         uses: actions/setup-node@v3
         with:
           node-version: ${{ matrix.node-version }}
-          cache: "yarn"
+          cache: 'yarn'
       - name: Install dependencies
         run: yarn --frozen-lockfile
       - name: Run lint
         run: yarn lint
+      - name: Run tests
+        run: yarn test
       - name: Run build
         run: yarn build

jest.config.ts

@@ -0,0 +1,20 @@
+import type { Config } from 'jest';
+import nextJest from 'next/jest.js';
+
+const createJestConfig = nextJest({
+  // Provide the path to your Next.js app to load next.config.js and .env files in your test environment
+  dir: './',
+});
+
+// Add any custom config to be passed to Jest
+const config: Config = {
+  collectCoverageFrom: ['src/**/*.ts*'],
+  coveragePathIgnorePatterns: ['src/components/*'],
+  coverageProvider: 'v8',
+  testEnvironment: 'jsdom',
+  // Add more setup options before each test is run
+  // setupFilesAfterEnv: ['<rootDir>/jest.setup.ts'],
+};
+
+// createJestConfig is exported this way to ensure that next/jest can load the Next.js config which is async
+export default createJestConfig(config);

package.json

@@ -8,7 +8,9 @@
     "dev": "next dev",
     "eslint": "next lint",
     "lint": "yarn eslint && yarn check-types",
-    "start": "next start"
+    "start": "next start",
+    "test": "jest --coverage",
+    "test:watch": "jest --watch"
   },
   "dependencies": {
     "@prisma/client": "5.8.1",
@@ -26,6 +28,9 @@
     "tailwindcss-animate": "1.0.7"
   },
   "devDependencies": {
+    "@testing-library/jest-dom": "6.2.1",
+    "@testing-library/react": "14.1.2",
+    "@types/jest": "29.5.11",
     "@types/node": "^20",
     "@types/react": "^18",
     "@types/react-dom": "^18",
@@ -34,10 +39,13 @@
     "eslint-config-next": "14.0.4",
     "eslint-config-prettier": "9.1.0",
     "eslint-plugin-prettier": "5.1.3",
+    "jest": "29.7.0",
+    "jest-environment-jsdom": "29.7.0",
     "postcss": "^8",
     "prettier": "3.2.4",
     "prisma": "5.8.1",
     "tailwindcss": "^3.3.0",
+    "ts-node": "10.9.2",
     "typescript": "^5"
   }
 }

src/lib/search/external/useExternalBookSearch.test.ts

@@ -0,0 +1,5 @@
+describe('useExternalBookSearch', () => {
+  it('should work', () => {
+    expect(true).toEqual(true);
+  });
+});