test(batch): migrate unit tests to Vitest (#2938)

Author: dreamorosi

.github/workflows/reusable-run-linting-check-and-unit-tests.yml

@@ -1,12 +1,63 @@
 name: Run unit tests
 
+# 
+# PROCESS
+#
+# 1. Checkout code
+# 2. Install dependencies & build project
+# 3. Run linting
+# 4. Run unit tests
+#
+# NOTES
+# We create different jobs for different workspaces of the monorepo, since we have slightly different requirements for each.
+# For example, the docs (`check-docs`), runs markdown linting, while the layer (`check-layer-publisher`), examples (`check-examples`),
+# and code snippets (`check-docs-snippets`) jobs run linting and unit tests but only for the current LTS version of Node.js.
+#
+# For the Powertools for AWS main features (aka `packages/*`), instead we run linting and unit tests for all the supported
+# versions of Node.js.
+#
+# Since #2938, we are in the process of improving our test suite, so we are gradually extracting the tests for each package
+# from (`run-linting-check-and-unit-tests-on-utilities`) to their own job, so we can run them in parallel using the matrix
+# strategy and reduce the time it takes to run the tests, as well as improve maintainer experience in case of failures.
+# 
+# USAGE
+#
+# NOTE: meant to be called by ./.github/workflows/pr-run-linting-check-and-unit-tests.yml when a PR is opened or updated,
+# or by ./.github/workflows/make-release.yml when a release is made.
+#
+
 on:
   workflow_call:
 
 permissions:
   contents: read
 
 jobs:
+  code-quality:
+    runs-on: ubuntu-latest
+    env:
+      NODE_ENV: dev
+    strategy:
+      matrix:
+        version: [18, 20]
+        workspace: ["packages/batch"]
+      fail-fast: false
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332  # v4.1.7
+      - name: Setup NodeJS
+        uses: actions/setup-node@1e60f620b9541d16bece96c5465dc8ee9832be0b # v4.0.3
+        with:
+          node-version: ${{ matrix.version }}
+          cache: "npm"
+      - name: Setup dependencies
+        uses: aws-powertools/actions/.github/actions/cached-node-modules@d406bac5563f1d8c793519a3eedfe620f6a14872
+        with:
+          nodeVersion: ${{ matrix.version }}
+      - name: Linting
+        run: npm run lint -w ${{ matrix.workspace }}
+      - name: Unit tests
+        run: npm run test:unit:coverage -w ${{ matrix.workspace }}
   run-linting-check-and-unit-tests-on-utilities:
     runs-on: ubuntu-latest
     env:

.husky/pre-push

@@ -7,4 +7,6 @@ npm t \
   -w packages/idempotency \
   -w packages/parameters \
   -w packages/parser \
-  -w packages/event-handler
+  -w packages/event-handler
+
+npx vitest --run --coverage --changed="$(git merge-base HEAD main)"

packages/batch/jest.config.cjs

@@ -10,9 +10,9 @@
     "access": "public"
   },
   "scripts": {
-    "test": "npm run test:unit",
-    "test:unit": "jest --group=unit --detectOpenHandles --coverage --verbose",
-    "jest": "jest --detectOpenHandles --verbose",
+    "test": "vitest --run",
+    "test:unit": "vitest --run",
+    "test:unit:coverage": "vitest --run --coverage.enabled --coverage.thresholds.100 --coverage.include='src/**'",
     "test:e2e:nodejs18x": "echo 'Not Implemented'",
     "test:e2e:nodejs20x": "echo 'Not Implemented'",
     "test:e2e": "echo 'Not Implemented'",
@@ -75,4 +75,4 @@
   "devDependencies": {
     "@aws-lambda-powertools/testing-utils": "file:../testing"
   }
-}
+}

packages/batch/package.json

@@ -115,9 +115,16 @@ abstract class BasePartialProcessor {
     /**
      * If this is a sync processor, user should have called processSync instead,
      * so we call the method early to throw the error early thus failing fast.
+     *
+     * The type casting is necessary to ensure that we have test coverage for the
+     * block of code that throws the error, without having to change the return type
+     * of the method. This is because this call will always throw an error.
      */
     if (this.constructor.name === 'BatchProcessorSync') {
-      await this.processRecord(this.records[0]);
+      return (await this.processRecord(this.records[0])) as (
+        | SuccessResponse
+        | FailureResponse
+      )[];
     }
     this.prepare();
 

packages/batch/src/BasePartialProcessor.ts

@@ -1,8 +1,4 @@
-/**
- * Test BasePartialBatchProcessor class
- *
- * @group unit/batch/class/basepartialbatchprocessor
- */
+import { afterAll, beforeEach, describe, expect, it, vi } from 'vitest';
 import { BasePartialBatchProcessor, EventType } from '../../src/index.js';
 import type {
   BaseRecord,
@@ -16,8 +12,7 @@ describe('Class: BasePartialBatchProcessor', () => {
   const ENVIRONMENT_VARIABLES = process.env;
 
   beforeEach(() => {
-    jest.clearAllMocks();
-    jest.resetModules();
+    vi.clearAllMocks();
     process.env = { ...ENVIRONMENT_VARIABLES };
   });
 
@@ -46,19 +41,19 @@ describe('Class: BasePartialBatchProcessor', () => {
   }
 
   describe('create custom batch partial processor', () => {
-    it('should create a custom batch partial processor', () => {
+    it('creates a custom batch partial processor', () => {
       // Act
       const processor = new MyPartialProcessor();
 
       // Assess
       expect(processor).toBeInstanceOf(BasePartialBatchProcessor);
     });
 
-    it('should process a batch of records', () => {
+    it('processes a batch of records', () => {
       // Prepare
       const processor = new MyPartialProcessor();
       const records = [sqsRecordFactory('success')];
-      const consoleSpy = jest.spyOn(console, 'log');
+      const consoleSpy = vi.spyOn(console, 'log').mockImplementation(() => {});
 
       // Act
       processor.register(records, sqsRecordHandler);

packages/batch/tests/helpers/populateEnvironmentVariables.ts

@@ -1,10 +1,6 @@
-/**
- * Test BatchProcessor class
- *
- * @group unit/batch/class/batchprocessor
- */
 import context from '@aws-lambda-powertools/testing-utils/context';
 import type { Context } from 'aws-lambda';
+import { afterAll, beforeEach, describe, expect, it, vi } from 'vitest';
 import {
   BatchProcessingError,
   BatchProcessor,
@@ -31,8 +27,7 @@ describe('Class: AsyncBatchProcessor', () => {
   };
 
   beforeEach(() => {
-    jest.clearAllMocks();
-    jest.resetModules();
+    vi.clearAllMocks();
     process.env = { ...ENVIRONMENT_VARIABLES };
   });
 
@@ -41,7 +36,7 @@ describe('Class: AsyncBatchProcessor', () => {
   });
 
   describe('Asynchronously processing SQS Records', () => {
-    test('Batch processing SQS records with no failures', async () => {
+    it('completes processing with no failures', async () => {
       // Prepare
       const firstRecord = sqsRecordFactory('success');
       const secondRecord = sqsRecordFactory('success');
@@ -59,7 +54,7 @@ describe('Class: AsyncBatchProcessor', () => {
       ]);
     });
 
-    test('Batch processing SQS records with some failures', async () => {
+    it('completes processing with with some failures', async () => {
       // Prepare
       const firstRecord = sqsRecordFactory('failure');
       const secondRecord = sqsRecordFactory('success');
@@ -86,7 +81,7 @@ describe('Class: AsyncBatchProcessor', () => {
       });
     });
 
-    test('Batch processing SQS records with all failures', async () => {
+    it('completes processing with all failures', async () => {
       // Prepare
       const firstRecord = sqsRecordFactory('failure');
       const secondRecord = sqsRecordFactory('failure');
@@ -106,7 +101,7 @@ describe('Class: AsyncBatchProcessor', () => {
   });
 
   describe('Asynchronously processing Kinesis Records', () => {
-    test('Batch processing Kinesis records with no failures', async () => {
+    it('completes processing with no failures', async () => {
       // Prepare
       const firstRecord = kinesisRecordFactory('success');
       const secondRecord = kinesisRecordFactory('success');
@@ -124,7 +119,7 @@ describe('Class: AsyncBatchProcessor', () => {
       ]);
     });
 
-    test('Batch processing Kinesis records with some failures', async () => {
+    it('completes processing with some failures', async () => {
       // Prepare
       const firstRecord = kinesisRecordFactory('failure');
       const secondRecord = kinesisRecordFactory('success');
@@ -151,7 +146,7 @@ describe('Class: AsyncBatchProcessor', () => {
       });
     });
 
-    test('Batch processing Kinesis records with all failures', async () => {
+    it('completes processing with all failures', async () => {
       // Prepare
       const firstRecord = kinesisRecordFactory('failure');
       const secondRecord = kinesisRecordFactory('failure');
@@ -171,7 +166,7 @@ describe('Class: AsyncBatchProcessor', () => {
   });
 
   describe('Asynchronously processing DynamoDB Records', () => {
-    test('Batch processing DynamoDB records with no failures', async () => {
+    it('completes processing with no failures', async () => {
       // Prepare
       const firstRecord = dynamodbRecordFactory('success');
       const secondRecord = dynamodbRecordFactory('success');
@@ -189,7 +184,7 @@ describe('Class: AsyncBatchProcessor', () => {
       ]);
     });
 
-    test('Batch processing DynamoDB records with some failures', async () => {
+    it('completes processing with some failures', async () => {
       // Prepare
       const firstRecord = dynamodbRecordFactory('failure');
       const secondRecord = dynamodbRecordFactory('success');
@@ -216,7 +211,7 @@ describe('Class: AsyncBatchProcessor', () => {
       });
     });
 
-    test('Batch processing DynamoDB records with all failures', async () => {
+    it('completes processing with all failures', async () => {
       // Prepare
       const firstRecord = dynamodbRecordFactory('failure');
       const secondRecord = dynamodbRecordFactory('failure');
@@ -236,7 +231,7 @@ describe('Class: AsyncBatchProcessor', () => {
   });
 
   describe('Batch processing with Lambda context', () => {
-    test('Batch processing when context is provided and handler accepts', async () => {
+    it('passes the context to the record handler', async () => {
       // Prepare
       const firstRecord = sqsRecordFactory('success');
       const secondRecord = sqsRecordFactory('success');
@@ -254,25 +249,7 @@ describe('Class: AsyncBatchProcessor', () => {
       ]);
     });
 
-    test('Batch processing when context is provided and handler does not accept', async () => {
-      // Prepare
-      const firstRecord = sqsRecordFactory('success');
-      const secondRecord = sqsRecordFactory('success');
-      const records = [firstRecord, secondRecord];
-      const processor = new BatchProcessor(EventType.SQS);
-
-      // Act
-      processor.register(records, asyncSqsRecordHandler, options);
-      const processedMessages = await processor.process();
-
-      // Assess
-      expect(processedMessages).toStrictEqual([
-        ['success', firstRecord.body, firstRecord],
-        ['success', secondRecord.body, secondRecord],
-      ]);
-    });
-
-    test('Batch processing when malformed context is provided and handler attempts to use', async () => {
+    it('throws an error when passing an invalid context object', async () => {
       // Prepare
       const firstRecord = sqsRecordFactory('success');
       const secondRecord = sqsRecordFactory('success');
@@ -289,7 +266,7 @@ describe('Class: AsyncBatchProcessor', () => {
     });
   });
 
-  test('When calling the sync process method, it should throw an error', () => {
+  it('throws an error when the sync process method is called', () => {
     // Prepare
     const processor = new BatchProcessor(EventType.SQS);