feat: migrate to ESM and vitest (#4461)

## Description

This PR migrates the TypeScript testing framework from Jest to Vitest
and transitions the codebase from CommonJS (CJS) to ECMAScript Modules
(ESM).

**Motivation: **

* **Moving from Jest to Vitest:**
* **Performance:** Vitest leverages Vite's build pipeline, resulting in
significantly faster test execution, especially in larger projects. This
speed improvement enhances developer productivity by providing quicker
feedback loops.
* **Vite Integration:** For projects already using Vite, Vitest offers
seamless integration, reducing configuration overhead and providing a
unified development experience.
* **Modern tooling:** Vitest is a modern test framework that is actively
being developed and provides a better developer experience.
* **Migrating from CJS to ESM:**
* **Modern JavaScript:** ESM is the official standard for module systems
in modern JavaScript, offering better static analysis, tree-shaking, and
overall performance.
* **Improved Compatibility:** ESM is the future of JavaScript modules
and ensures better compatibility with modern tooling and libraries.
* **Simplified Dependency Management:** ESM's static imports allow for
more efficient dependency management and better optimization by
bundlers.

**Changes:**

* Replaced Jest with Vitest for unit testing.
* Updated test files to adhere to Vitest syntax.
* Updated configuration files to reflect the changes (e.g.,
`package.json`, `tsconfig.json`).

**Testing:**

* The changes should not introduce any functional regressions.
Thoroughly verify existing test suites using Vitest.
* It is advisable to clear any local cache, such as node\_modules and
dist folders, before building the lambda functions yourself.
* Chages are tested with
  * Default example
  * Multi runner example

**Related Issues:**

* Fixes #3964
* Fixes #4366

**Potential Risks:**

* While the migration aims for seamless transition, there's a
possibility of encountering minor compatibility issues during the
initial build or test runs. Thorough testing and cache clearing should
mitigate these risks.

**Additional Notes:**

* This migration modernizes the project's tooling and module system,
laying a foundation for future improvements and maintainability.

---------

Co-authored-by: Nadav Sinai <[email protected]>

Author: npalm

.devcontainer/devcontainer.json

@@ -16,11 +16,10 @@
         "dbaeumer.vscode-eslint",
         "editorconfig.editorconfig",
         "esbenp.prettier-vscode",
-        "firsttris.vscode-jest-runner",
         "hashicorp.hcl",
         "hashicorp.terraform",
         "hashicorp.terraform",
-        "orta.vscode-jest",
+        "vitest.explorer",
         "yzhang.markdown-all-in-one"
       ]
     }

.vscode/extensions.json

@@ -6,6 +6,6 @@
     "editorconfig.editorconfig",
     "yzhang.markdown-all-in-one",
     "hashicorp.terraform",
-    "firsttris.vscode-jest-runner"
+    "vitest.explorer"
   ]
 }

.vscode/gh-runners.code-workspace

@@ -8,11 +8,5 @@
       "name": "🚀 lambdas",
       "path": "../lambdas"
     }
-  ],
-  "settings": {
-    "jest.autoRun": "on",
-    "jest.disabledWorkspaceFolders": [
-      "✨ root"
-    ]
-  }
+  ]
 }

.vscode/settings.json

@@ -1 +1,3 @@
-{}
+{
+  "jest.enable": false
+}

lambdas/.gitignore

@@ -1,6 +1,6 @@
 node_modules/
 build/
-dist/
+**/dist/
 *.log
 
 # Ignore all yarn.lock files except the one in the root

lambdas/.vscode/settings.json

@@ -0,0 +1,2 @@
+// Setup AWS SDK client mock matchers
+import 'aws-sdk-client-mock-jest/vitest';

lambdas/aws-vitest-setup.ts

@@ -2,48 +2,33 @@
   "name": "@aws-github-runner/ami-housekeeper",
   "version": "1.0.0",
   "main": "lambda.ts",
+  "type": "module",
   "license": "MIT",
   "scripts": {
     "start": "ts-node-dev src/local.ts",
     "test": "NODE_ENV=test nx test",
     "test:watch": "NODE_ENV=test nx test --watch",
-    "lint": "yarn eslint src",
+    "lint": "eslint src",
     "watch": "ts-node-dev --respawn --exit-child src/local.ts",
     "build": "ncc build src/lambda.ts -o dist",
-    "dist": "yarn build && cd dist && zip ../ami-housekeeper.zip index.js",
+    "dist": "yarn build && cp package.json dist/ && cd dist && zip ../ami-housekeeper.zip *",
     "format": "prettier --write \"**/*.ts\"",
     "format-check": "prettier --check \"**/*.ts\"",
     "all": "yarn build && yarn format && yarn lint && yarn test"
   },
   "devDependencies": {
-    "@trivago/prettier-plugin-sort-imports": "^5.2.2",
-    "@types/aws-lambda": "^8.10.146",
-    "@types/jest": "^29.5.14",
-    "@types/node": "^22.13.9",
-    "@typescript-eslint/eslint-plugin": "^8.25.0",
-    "@typescript-eslint/parser": "^8.25.0",
+    "@aws-sdk/types": "^3.734.0",
+    "@types/aws-lambda": "^8.10.147",
     "@vercel/ncc": "^0.38.3",
     "aws-sdk-client-mock": "^4.1.0",
-    "aws-sdk-client-mock-jest": "^4.1.0",
-    "eslint": "^8.57.0",
-    "eslint-plugin-prettier": "5.2.3",
-    "jest": "^29.7.0",
-    "jest-mock": "^29.7.0",
-    "jest-mock-extended": "^3.0.7",
-    "nock": "^14.0.1",
-    "prettier": "3.4.2",
-    "ts-jest": "^29.2.5",
-    "ts-node": "^10.9.2",
-    "ts-node-dev": "^2.0.0"
+    "aws-sdk-client-mock-jest": "^4.1.0"
   },
   "dependencies": {
     "@aws-github-runner/aws-powertools-util": "*",
     "@aws-github-runner/aws-ssm-util": "*",
-    "@aws-sdk/client-ec2": "^3.764.0",
+    "@aws-sdk/client-ec2": "^3.767.0",
     "@aws-sdk/client-ssm": "^3.759.0",
-    "@aws-sdk/types": "^3.734.0",
-    "cron-parser": "^4.9.0",
-    "typescript": "^5.7.3"
+    "cron-parser": "^4.9.0"
   },
   "nx": {
     "includedScripts": [

lambdas/functions/ami-housekeeper/jest.config.ts

@@ -14,9 +14,10 @@ import {
   SSMClient,
 } from '@aws-sdk/client-ssm';
 import { mockClient } from 'aws-sdk-client-mock';
-import 'aws-sdk-client-mock-jest';
+import 'aws-sdk-client-mock-jest/vitest';
 
 import { AmiCleanupOptions, amiCleanup, defaultAmiCleanupOptions } from './ami';
+import { describe, it, expect, beforeEach, vi } from 'vitest';
 
 process.env.AWS_REGION = 'eu-east-1';
 const deleteAmisOlderThenDays = 30;
@@ -76,7 +77,7 @@ const ssmParameters: DescribeParametersCommandOutput = {
 
 describe("delete AMI's", () => {
   beforeEach(() => {
-    jest.resetAllMocks();
+    vi.resetAllMocks();
     mockEC2Client.reset();
     mockSSMClient.reset();