CCM-11228: Enhance letter repository tests and error handling

Author: m-houston

internal/datastore/src/__test__/letter-repository.test.ts

@@ -64,10 +64,41 @@ describe('LetterRepository', () => {
 
   test('adds a letter to the database', async () => {
     await letterRepository.putLetter(createLetter('supplier1', 'letter1'));
-
     await checkLetterExists('supplier1', 'letter1');
   });
 
+  test('fetches a letter by id', async () => {
+    await letterRepository.putLetter(createLetter('supplier1', 'letter1'));
+    const letter = await letterRepository.getLetterById('supplier1', 'letter1');
+    expect(letter).toEqual(expect.objectContaining({
+      id: 'letter1',
+      supplierId: 'supplier1',
+      specificationId: 'specification1',
+      groupId: 'group1',
+      status: 'PENDING'
+    }));
+  });
+
+  test('throws an error when fetching a letter that does not exist', async () => {
+    await expect(letterRepository.getLetterById('supplier1', 'letter1'))
+      .rejects.toThrow("Letter with id letter1 not found for supplier supplier1");
+  });
+
+  test('throws an error when creating a letter which already exists', async () => {
+    await letterRepository.putLetter(createLetter('supplier1', 'letter1'));
+    await expect(letterRepository.putLetter(createLetter('supplier1', 'letter1')))
+      .rejects.toThrow("Letter with id letter1 already exists for supplier supplier1");
+  });
+
+  test('rethrows errors from DynamoDB when creating a letter', async () => {
+    const misconfiguredRepository = new LetterRepository(db.docClient, logger, {
+      ...db.config,
+      lettersTableName: 'nonexistent-table'
+    });
+    await expect(misconfiguredRepository.putLetter(createLetter('supplier1', 'letter1')))
+      .rejects.toThrow('Cannot do operations on a non-existent table');
+  });
+
   test('updates a letter\'s status in the database', async () => {
     await letterRepository.putLetter(createLetter('supplier1', 'letter1', 'PENDING'));
     await checkLetterStatus('supplier1', 'letter1', 'PENDING');
@@ -90,9 +121,17 @@ describe('LetterRepository', () => {
   });
 
   test('can\t update a letter that does not exist', async () => {
-    await expect(async () => {
-      await letterRepository.updateLetterStatus('supplier1', 'letter1', 'DELIVERED');
-    }).rejects.toThrow('Letter with id letter1 not found for supplier supplier1');
+    await expect(letterRepository.updateLetterStatus('supplier1', 'letter1', 'DELIVERED'))
+      .rejects.toThrow('Letter with id letter1 not found for supplier supplier1');
+  });
+
+  test('update letter status rethrows errors from DynamoDB', async () => {
+    const misconfiguredRepository = new LetterRepository(db.docClient, logger, {
+      ...db.config,
+      lettersTableName: 'nonexistent-table'
+    });
+    await expect(misconfiguredRepository.updateLetterStatus(createLetter('supplier1', 'letter1', 'DELIVERED')))
+      .rejects.toThrow('Cannot do operations on a non-existent table');
   });
 
   test('should return a list of letters matching status', async () => {
@@ -145,6 +184,12 @@ describe('LetterRepository', () => {
     expect(secondPage.letters[48].id).toBe('letter099');
   });
 
+  test('letter list should return empty when no letters match status', async () => {
+    const page = await letterRepository.getLettersByStatus('supplier1', 'PENDING');
+    expect(page.letters).toHaveLength(0);
+    expect(page.lastEvaluatedKey).toBeUndefined();
+  });
+
   test('letter list should warn about invalid data', async () => {
     await letterRepository.putLetter(createLetter('supplier1', 'letter1'));
     await db.docClient.send(new PutCommand({

internal/datastore/src/letter-repository.ts

@@ -29,12 +29,18 @@ export class LetterRepository {
       ...letter,
       supplierStatus: `${letter.supplierId}#${letter.status}`
     };
-    await this.ddbClient.send(new PutCommand({
-      TableName: this.config.lettersTableName,
-      Item: letterDb,
-      ConditionExpression: 'attribute_not_exists(id)', // Ensure id is unique
-    }));
-
+    try {
+      await this.ddbClient.send(new PutCommand({
+        TableName: this.config.lettersTableName,
+        Item: letterDb,
+        ConditionExpression: 'attribute_not_exists(id)', // Ensure id is unique
+      }));
+    } catch (error) {
+      if (error instanceof Error && error.name === 'ConditionalCheckFailedException') {
+        throw new Error(`Letter with id ${letter.id} already exists for supplier ${letter.supplierId}`);
+      }
+      throw error;
+    }
     return letterDb;
   }
 
@@ -73,11 +79,9 @@ export class LetterRepository {
       ExclusiveStartKey: extendedOptions.exclusiveStartKey
     }));
 
-    if (!result.Items) {
-      throw new Error(`No letters found for supplier ${supplierId} with status ${status}`);
-    }
     return {
-      letters: result.Items.map(item => LetterSchema.safeParse(item))
+      // Items is an empty array if no items match the query
+      letters: result.Items!.map(item => LetterSchema.safeParse(item))
         .filter((result) => {
           if (!result.success) {
             this.log.warn(`Invalid letter data: ${result.error}`);
@@ -118,9 +122,6 @@ export class LetterRepository {
       throw error;
     }
 
-    if (!result.Attributes) {
-      throw new Error(`Letter with id ${letterId} not found for supplier ${supplierId}`);
-    }
     this.log.debug(`Updated letter ${letterId} to status ${status}`);
     return LetterSchema.parse(result.Attributes);
   }