Fixed the tests for DynamoDB and added a note for using innerSchema with DynamoDB

Author: sdangol

docs/features/batch.md

@@ -358,6 +358,9 @@ Available transformers by event type:
     --8<-- "examples/snippets/batch/samples/parser_SQS.json"
     ```
 
+!!! note
+    If `innerSchema` is used with DynamoDB streams, the schema will be applied to both the `NewImage` and the `OldImage` by default. If you want to have separate schema for both, you will need to extend the schema and use the full schema for parsing.
+
 #### Using full event schema
 
 For complete control over validation, extend the built-in schemas with your custom payload schema. This approach gives you full control over the entire event structure.

packages/batch/src/BatchProcessor.ts

@@ -33,7 +33,7 @@ import type { BaseRecord, FailureResponse, SuccessResponse } from './types.js';
  *   });
  * ```
  *
- * **Process batch triggered by Kinesis Data Streams*
+ * **Process batch triggered by Kinesis Data Streams**
  *
  * @example
  * ```typescript
@@ -113,6 +113,39 @@ import type { BaseRecord, FailureResponse, SuccessResponse } from './types.js';
  *   });
  * ```
  *
+ * **Process batch with inner schema validation**
+ *
+ * @example
+ * ```typescript
+ * import {
+ *   BatchProcessor,
+ *   EventType,
+ *   processPartialResponse,
+ * } from '@aws-lambda-powertools/batch';
+ * import { parser } from '@aws-lambda-powertools/batch/parser';
+ * import type { SQSHandler } from 'aws-lambda';
+ * import { z } from 'zod';
+ *
+ * const myItemSchema = z.object({ name: z.string(), age: z.number() });
+ *
+ * const processor = new BatchProcessor(EventType.SQS, {
+ *   parser,
+ *   innerSchema: myItemSchema,
+ * });
+ *
+ * const recordHandler = async (record) => {
+ *   // record is now fully typed and validated
+ *   console.log(record.body.name, record.body.age);
+ * };
+ *
+ * export const handler: SQSHandler = async (event, context) =>
+ *   processPartialResponse(event, recordHandler, processor, {
+ *     context,
+ *   });
+ * ```
+ *
+ * Note: If `innerSchema` is used with DynamoDB streams, the schema will be applied to both the NewImage and the OldImage by default. If you want to have separate schema for both, you will need to extend the schema and use the full schema for parsing.
+ *
  * @param eventType - The type of event to process (SQS, Kinesis, DynamoDB)
  */
 class BatchProcessor extends BasePartialBatchProcessor {

packages/batch/tests/helpers/factories.ts

@@ -61,6 +61,7 @@ const dynamodbRecordFactory = (body: string): DynamoDBRecord => {
     eventVersion: '1.0',
     dynamodb: {
       Keys: { Id: { N: '101' } },
+      OldImage: { Message: { S: body } },
       NewImage: { Message: { S: body } },
       StreamViewType: 'NEW_AND_OLD_IMAGES',
       SequenceNumber: seq,

packages/batch/tests/unit/parsing.test.ts

@@ -78,7 +78,8 @@ describe('Batch processing with Parser Integration', () => {
         parser,
         schema: DynamoDBStreamRecord.extend({
           dynamodb: DynamoDBStreamChangeRecordBase.extend({
-            NewImage: DynamoDBMarshalled(customSchema).optional(),
+            NewImage: DynamoDBMarshalled(customSchema),
+            OldImage: DynamoDBMarshalled(customSchema),
           }),
         }),
       },
@@ -278,7 +279,7 @@ describe('Batch processing with Parser Integration', () => {
           ],
         });
         expect(console.debug).toHaveBeenCalledWith(
-          'dynamodb.NewImage.Message: Invalid input: expected string, received number'
+          'dynamodb.NewImage.Message: Invalid input: expected string, received number; dynamodb.OldImage.Message: Invalid input: expected string, received number'
         );
       });
     }
@@ -314,7 +315,6 @@ describe('Batch processing with Parser Integration', () => {
     const records = [firstRecord, secondRecord];
     const processor = new BatchProcessor(EventType.SQS, {
       parser,
-      // @ts-expect-error - we are explicitly testing a wrong schema vendor
       innerSchema: unsupportedSchema,
       transformer: 'json',
     });
@@ -334,6 +334,7 @@ describe('Batch processing with Parser Integration', () => {
     const secondRecord = sqsRecordFactory(JSON.stringify(successPayload2));
     const records = [firstRecord, secondRecord];
 
+    // @ts-expect-error - we are explicitly testing without a schema
     const processor = new BatchProcessor(EventType.SQS, {
       parser,
       transformer: 'json',
@@ -363,7 +364,6 @@ describe('Batch processing with Parser Integration', () => {
     const records = [firstRecord, secondRecord];
     const processor = new BatchProcessor(EventType.SQS, {
       parser,
-      // @ts-expect-error - we are explicitly testing a wrong schema vendor
       innerSchema: unsupportedSchema,
       transformer: 'json',
       logger,