fix: correct failing unit tests for product and import job services

- test_create_import_job_database_error: Monkeypatch db.flush instead
  of db.commit since service uses flush() per architecture rules
- test_create_product_already_exists: Store product_id before exception
  and rollback session to clear PendingRollbackError state
- test_delete_product_success: Add db.flush() to delete_product service
  method to ensure deletion is applied before verification

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tests/unit/services/test_marketplace_service.py

@@ -59,10 +59,10 @@ class TestMarketplaceImportJobService:
             marketplace="Amazon",
         )
 
-        def mock_commit():
-            raise Exception("Database commit failed")
+        def mock_flush():
+            raise Exception("Database flush failed")
 
-        monkeypatch.setattr(db, "commit", mock_commit)
+        monkeypatch.setattr(db, "flush", mock_flush)
 
         with pytest.raises(ValidationException) as exc_info:
             self.service.create_import_job(db, request, test_vendor, test_user)

tests/unit/services/test_product_service.py

@@ -87,8 +87,11 @@ class TestProductService:
 
     def test_create_product_already_exists(self, db, test_marketplace_product):
         """Test creating product with existing ID raises MarketplaceProductAlreadyExistsException"""
+        # Store the product ID before the exception (session may be invalid after)
+        existing_product_id = test_marketplace_product.marketplace_product_id
+
         product_data = MarketplaceProductCreate(
-            marketplace_product_id=test_marketplace_product.marketplace_product_id,  # Use existing product ID
+            marketplace_product_id=existing_product_id,  # Use existing product ID
             title="Duplicate MarketplaceProduct",
             price="29.99",
         )
@@ -96,12 +99,15 @@ class TestProductService:
         with pytest.raises(MarketplaceProductAlreadyExistsException) as exc_info:
             self.service.create_product(db, product_data)
 
+        # Rollback to clear the session's invalid state from IntegrityError
+        db.rollback()
+
         assert exc_info.value.error_code == "PRODUCT_ALREADY_EXISTS"
-        assert test_marketplace_product.marketplace_product_id in str(exc_info.value)
+        assert existing_product_id in str(exc_info.value)
         assert exc_info.value.status_code == 409
         assert (
             exc_info.value.details.get("marketplace_product_id")
-            == test_marketplace_product.marketplace_product_id
+            == existing_product_id
         )
 
     def test_create_product_invalid_price(self, db):