refactor: extract assetPath as standalone pure function (#10651)

## Summary

Extract `assetPath` from a `ComfyPage` method to a standalone pure
function, removing unnecessary coupling to the page object.

## Changes

- **What**: Moved `assetPath` to
`browser_tests/fixtures/utils/paths.ts`. `DragDropHelper` and
`WorkflowHelper` import it directly instead of receiving it via
`ComfyPage`. `ComfyPage.assetPath` kept as thin delegate for backward
compat.

## Review Focus

Structural-only refactor — no behavioral changes. The function was
already pure (no `this`/`page` usage).

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10651-refactor-extract-assetPath-as-standalone-pure-function-3316d73d365081c0b0e0ce6dde57ef8e)
by [Unito](https://www.unito.io)

browser_tests/fixtures/ComfyPage.ts

@@ -40,6 +40,7 @@ import { SubgraphHelper } from './helpers/SubgraphHelper'
 import { ToastHelper } from './helpers/ToastHelper'
 import { WorkflowHelper } from './helpers/WorkflowHelper'
 import type { NodeReference } from './utils/litegraphUtils'
+import { assetPath } from './utils/paths'
 import type { WorkspaceStore } from '../types/globals'
 
 dotenvConfig()
@@ -242,7 +243,7 @@ export class ComfyPage {
     this.workflow = new WorkflowHelper(this)
     this.contextMenu = new ContextMenu(page)
     this.toast = new ToastHelper(page)
-    this.dragDrop = new DragDropHelper(page, this.assetPath.bind(this))
+    this.dragDrop = new DragDropHelper(page)
     this.featureFlags = new FeatureFlagHelper(page)
     this.command = new CommandHelper(page)
     this.bottomPanel = new BottomPanel(page)
@@ -343,8 +344,9 @@ export class ComfyPage {
     await this.nextFrame()
   }
 
+  /** @deprecated Use standalone `assetPath` from `browser_tests/fixtures/utils/assetPath` directly. */
   public assetPath(fileName: string) {
-    return `./browser_tests/assets/${fileName}`
+    return assetPath(fileName)
   }
 
   async goto() {

browser_tests/fixtures/helpers/DragDropHelper.ts

@@ -4,12 +4,10 @@ import type { Page } from '@playwright/test'
 
 import type { Position } from '../types'
 import { getMimeType } from './mimeTypeUtil'
+import { assetPath } from '../utils/paths'
 
 export class DragDropHelper {
-  constructor(
-    private readonly page: Page,
-    private readonly assetPath: (fileName: string) => string
-  ) {}
+  constructor(private readonly page: Page) {}
 
   private async nextFrame(): Promise<void> {
     await this.page.evaluate(() => {
@@ -49,7 +47,7 @@ export class DragDropHelper {
     } = { dropPosition, preserveNativePropagation }
 
     if (fileName) {
-      const filePath = this.assetPath(fileName)
+      const filePath = assetPath(fileName)
       const buffer = readFileSync(filePath)
 
       evaluateParams.fileName = fileName

browser_tests/fixtures/helpers/WorkflowHelper.ts

@@ -7,6 +7,7 @@ import type {
 } from '../../../src/platform/workflow/validation/schemas/workflowSchema'
 import type { WorkspaceStore } from '../../types/globals'
 import type { ComfyPage } from '../ComfyPage'
+import { assetPath } from '../utils/paths'
 
 type FolderStructure = {
   [key: string]: FolderStructure | string
@@ -20,7 +21,7 @@ export class WorkflowHelper {
 
     for (const [key, value] of Object.entries(structure)) {
       if (typeof value === 'string') {
-        const filePath = this.comfyPage.assetPath(value)
+        const filePath = assetPath(value)
         result[key] = readFileSync(filePath, 'utf-8')
       } else {
         result[key] = this.convertLeafToContent(value)
@@ -59,7 +60,7 @@ export class WorkflowHelper {
 
   async loadWorkflow(workflowName: string) {
     await this.comfyPage.workflowUploadInput.setInputFiles(
-      this.comfyPage.assetPath(`${workflowName}.json`)
+      assetPath(`${workflowName}.json`)
     )
     await this.comfyPage.nextFrame()
   }

browser_tests/fixtures/utils/paths.ts

@@ -0,0 +1,3 @@
+export function assetPath(fileName: string): string {
+  return `./browser_tests/assets/${fileName}`
+}