fix: allow backorder variants to be added to cart even if no locations (#12083)

* fix: allow backorder variants to be added to cart even if no locations

* document and unit test prepareConfirmInventoryInput

integration-tests/modules/__tests__/index/query-index.spec.ts

@@ -80,7 +80,7 @@ async function populateData(api: any) {
       console.log(err)
     })
 
-  await setTimeout(2000)
+  await setTimeout(10000)
 }
 
 process.env.ENABLE_INDEX_MODULE = "true"

integration-tests/modules/__tests__/index/search.spec.ts

@@ -153,7 +153,7 @@ medusaIntegrationTestRunner({
           })
 
         // Timeout to allow indexing to finish
-        await setTimeout(4000)
+        await setTimeout(10000)
 
         const { data: results } = await fetchAndRetry(
           async () =>

integration-tests/modules/__tests__/order/draft-order.spec.ts

@@ -17,7 +17,7 @@ import {
 } from "../../../helpers/create-admin-user"
 import { setupTaxStructure } from "../fixtures"
 
-jest.setTimeout(50000)
+jest.setTimeout(100000)
 
 const env = { MEDUSA_FF_MEDUSA_V2: true }
 
@@ -165,6 +165,14 @@ medusaIntegrationTestRunner({
               inventory_item_id: inventoryItem.id,
             },
           },
+          {
+            [Modules.PRODUCT]: {
+              variant_id: product_2.variants[0].id,
+            },
+            [Modules.INVENTORY]: {
+              inventory_item_id: inventoryItem.id,
+            },
+          },
         ])
 
         await setupTaxStructure(taxModule)