add jest

jest.config.js

@@ -0,0 +1,14 @@
+/** @type {import('ts-jest/dist/types').InitialOptionsTsJest} */
+// eslint-disable-next-line import/no-commonjs
+module.exports = {
+  verbose: true,
+  preset: 'ts-jest',
+  collectCoverage: true,
+  collectCoverageFrom: ['src/**/*.ts', '!**/node_modules/**', '!src/seeds/**', '!build/**'],
+  coverageThreshold: {
+    global: {
+      lines: 86,
+    },
+  },
+  setupFiles: ['./test/testSetup.ts'],
+}

package.json

@@ -20,7 +20,8 @@
     "dev": "TZ=UTC nodemon -w src --ext ts,json --exec ts-node -r tsconfig-paths/register src/index.ts",
     "test:lint": "npm run test:lint:eslint && npm run test:lint:remark",
     "test:lint:eslint": "eslint --ext .ts,.tsx,.js,.jsx,.json,.yml,.yaml --max-warnings 0 --ignore-path .gitignore .",
-    "test:lint:remark": "remark . --quiet --frail"
+    "test:lint:remark": "remark . --quiet --frail",
+    "test:unit": "TZ=UTC jest --runInBand --forceExit --detectOpenHandles"
   },
   "dependencies": {
     "apollo-server-express": "^3.13.0",
@@ -31,9 +32,11 @@
   "devDependencies": {
     "@eslint-community/eslint-plugin-eslint-comments": "^4.1.0",
     "@types/express": "^4.17.21",
+    "@types/jest": "^29.5.10",
     "@types/node": "^20.10.1",
     "@typescript-eslint/eslint-plugin": "^6.13.1",
     "@typescript-eslint/parser": "^6.13.1",
+    "apollo-server-testing": "^2.25.3",
     "eslint": "^8.54.0",
     "eslint-config-prettier": "^9.0.0",
     "eslint-config-standard": "^17.1.0",
@@ -45,6 +48,7 @@
     "eslint-plugin-security": "^1.7.1",
     "eslint-plugin-vitest": "^0.3.10",
     "eslint-plugin-yml": "^1.10.0",
+    "jest": "^29.7.0",
     "nodemon": "^3.0.1",
     "prettier": "^3.1.0",
     "remark-cli": "^12.0.0",
@@ -52,12 +56,15 @@
     "remark-preset-lint-consistent": "^5.1.2",
     "remark-preset-lint-markdown-style-guide": "^5.1.3",
     "remark-preset-lint-recommended": "^6.1.3",
+    "ts-jest": "^29.1.1",
     "ts-node": "^10.9.1",
     "tsc-watch": "^6.0.4",
     "tsconfig-paths": "^4.2.0",
     "typescript": "^5.3.2"
   },
   "imports": {
-    "#types/*": "./src/graphql/types/*"
+    "#graphql/*": "./src/graphql/*",
+    "#types/*": "./src/graphql/types/*",
+    "#test/*": "./test/*"
   }
 }

src/graphql/resolvers/HelloResolver.spec.ts

@@ -0,0 +1,22 @@
+import { ApolloServerTestClient } from 'apollo-server-testing'
+
+import { testEnvironment } from '#test/helpers'
+
+let query: ApolloServerTestClient['query']
+
+beforeAll(async () => {
+  const testEnv = await testEnvironment()
+  query = testEnv.query
+})
+
+describe('HelloResolver', () => {
+  it('return "Hello World!"', async () => {
+    await expect(query({ query: '{ hello { hello } }' })).resolves.toMatchObject({
+      data: {
+        hello: {
+          hello: 'Hello world!',
+        },
+      },
+    })
+  })
+})

test/helpers.ts

@@ -0,0 +1,12 @@
+import { ApolloServer } from 'apollo-server-express'
+import { createTestClient } from 'apollo-server-testing'
+
+import { schema } from '#graphql/schema'
+
+export const testEnvironment = async () => {
+  const server = new ApolloServer({
+    schema: await schema(),
+  })
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  return createTestClient(server as any)
+}

test/testSetup.ts

@@ -0,0 +1,2 @@
+// eslint-disable-next-line import/no-unassigned-import
+import 'reflect-metadata'

tsconfig.json

@@ -8,7 +8,9 @@
     "baseUrl": ".",
     "lib": ["ESNext"],
     "paths": {
-      "#types/*": ["./src/graphql/types/*"]
+      "#graphql/*": ["./src/graphql/*"],
+      "#types/*": ["./src/graphql/types/*"],
+      "#test/*": ["./test/*"]
     },
     "outDir": "./build/src",
     "esModuleInterop": true,