Load the sortable engine after its mock

vi.doMock only affects later imports, so the statically imported
createSortableRoot would have pulled in the real auto-scroll module
first and the mock would have stopped applying silently. A type import
plus a lazy binding restores the ordering in both engine specs, and
drops vi.hoisted with it.

The preview spec also loses the file-split rationale that cited a
shared module registry, which isolate:true removed. The split itself
stands: the sibling renders previews for real.

Author: myabc

frontend/src/common/drag-and-drop/sortable-lists-engine.preview.spec.ts

@@ -29,31 +29,37 @@
 // The drag preview's `getOffset` decides where the pointer sits on the
 // preview, and Pragmatic only hands it to the real `setCustomNativeDragPreview`
 // — nothing observable from the outside. So this file mocks that module and
-// reads the options back, which the sibling engine spec cannot do: it renders
-// previews for real. Separate file rather than a mock added there, because the
-// suite runs with `isolate: false` and shares one module registry.
+// reads the options back. It stays a separate file from the sibling engine
+// spec because that one renders previews for real, and one file cannot both
+// stub and exercise the same module.
 
 import { vi } from 'vitest';
 import { NativeDragSimulation } from 'core-common/drag-and-drop/testing/native-drag-simulation';
-import { createSortableRoot } from './sortable-lists-engine';
+import type { createSortableRoot as createSortableRootFn } from './sortable-lists-engine';
 
-const { previewCalls } = vi.hoisted(() => ({
-  previewCalls: [] as {
-    getOffset?:(args:{ container:HTMLElement }) => { x:number; y:number };
-  }[],
-}));
+// `doMock` is not hoisted, so this initialises before the factory below runs
+// and a plain const does the job `vi.hoisted()` used to.
+const previewCalls:{
+  getOffset?:(args:{ container:HTMLElement }) => { x:number; y:number };
+}[] = [];
 
-vi.mock('@atlaskit/pragmatic-drag-and-drop/element/set-custom-native-drag-preview', () => ({
+vi.doMock('@atlaskit/pragmatic-drag-and-drop/element/set-custom-native-drag-preview', () => ({
   setCustomNativeDragPreview: (options:{
     getOffset?:(args:{ container:HTMLElement }) => { x:number; y:number };
   }) => {
     previewCalls.push(options);
   },
 }));
 
+let createSortableRoot:typeof createSortableRootFn;
+
 describe('createSortableRoot drag preview offset', () => {
   let cleanupFns:(() => void)[] = [];
 
+  beforeAll(async () => {
+    ({ createSortableRoot } = await import('./sortable-lists-engine'));
+  });
+
   beforeEach(() => { previewCalls.length = 0; });
 
   afterEach(() => {

frontend/src/common/drag-and-drop/sortable-lists-engine.spec.ts

@@ -32,23 +32,23 @@ import {
   centerOf,
   towardsEdgeOf,
 } from 'core-common/drag-and-drop/testing/native-drag-simulation';
-import {
-  createSortableRoot,
-  type SortableDropIntent,
-  type SortableDropTransaction,
-  type SortableSource,
+import type {
+  createSortableRoot as createSortableRootFn,
+  SortableDropIntent,
+  SortableDropTransaction,
+  SortableSource,
 } from './sortable-lists-engine';
 
-const { autoScrollRegistrations } = vi.hoisted(() => ({
-  autoScrollRegistrations: [] as {
-    element:Element;
-    getAllowedAxis:() => string;
-    cleanup:() => void;
-    cleaned:boolean;
-  }[],
-}));
+// `doMock` is not hoisted, so this initialises before the factory below runs
+// and a plain const does the job `vi.hoisted()` used to.
+const autoScrollRegistrations:{
+  element:Element;
+  getAllowedAxis:() => string;
+  cleanup:() => void;
+  cleaned:boolean;
+}[] = [];
 
-vi.mock('@atlaskit/pragmatic-drag-and-drop-auto-scroll/element', () => ({
+vi.doMock('@atlaskit/pragmatic-drag-and-drop-auto-scroll/element', () => ({
   autoScrollForElements: (args:{ element:Element; getAllowedAxis:() => string }) => {
     const entry = {
       element: args.element,
@@ -62,6 +62,8 @@ vi.mock('@atlaskit/pragmatic-drag-and-drop-auto-scroll/element', () => ({
   },
 }));
 
+let createSortableRoot:typeof createSortableRootFn;
+
 const liveRegistrations = () => autoScrollRegistrations.filter((r) => !r.cleaned);
 
 function buildList(items:string[]):{ root:HTMLElement; rows:HTMLElement[] } {
@@ -145,6 +147,10 @@ function buildCardGrid(items:string[], columns:number):{ root:HTMLElement; cards
 describe('createSortableRoot', () => {
   let cleanupFns:(() => void)[] = [];
 
+  beforeAll(async () => {
+    ({ createSortableRoot } = await import('./sortable-lists-engine'));
+  });
+
   beforeEach(() => { autoScrollRegistrations.length = 0; });
 
   afterEach(() => {