Add validateExistingTableImport _id support test

packages/server/src/api/routes/tests/table.spec.ts

@@ -1,4 +1,4 @@
-import { context, events } from "@budibase/backend-core"
+import { context, docIds, events } from "@budibase/backend-core"
 import {
   AutoFieldSubType,
   BBReferenceFieldSubType,
@@ -1078,6 +1078,37 @@ describe.each([
           },
         })
       })
+
+      isInternal &&
+        it("can reimport _id fields for internal tables", async () => {
+          const table = await config.api.table.save(
+            tableForDatasource(datasource, {
+              primary: ["id"],
+              schema: basicSchema,
+            })
+          )
+          const result = await config.api.table.validateExistingTableImport({
+            tableId: table._id,
+            rows: [
+              {
+                _id: docIds.generateRowID(table._id!),
+                id: generator.natural(),
+                name: generator.first(),
+              },
+            ],
+          })
+
+          expect(result).toEqual({
+            allValid: true,
+            errors: {},
+            invalidColumns: [],
+            schemaValidation: {
+              _id: true,
+              id: true,
+              name: true,
+            },
+          })
+        })
     })
   })
 })