[Test] Add per-workflow viewport comparison test (#3867)

Co-authored-by: github-actions <github-actions@github.com>

browser_tests/tests/interaction.spec.ts

@@ -1,6 +1,6 @@
 import { expect } from '@playwright/test'
 
-import { comfyPageFixture as test } from '../fixtures/ComfyPage'
+import { type ComfyPage, comfyPageFixture as test } from '../fixtures/ComfyPage'
 
 test.describe('Item Interaction', () => {
   test('Can select/delete all items', async ({ comfyPage }) => {
@@ -689,3 +689,42 @@ test.describe('Load duplicate workflow', () => {
     expect(await comfyPage.getGraphNodesCount()).toBe(1)
   })
 })
+
+test.describe('Viewport settings', () => {
+  test.beforeEach(async ({ comfyPage }) => {
+    await comfyPage.setSetting('Comfy.UseNewMenu', 'Top')
+    await comfyPage.setSetting('Comfy.Workflow.WorkflowTabsPosition', 'Topbar')
+
+    await comfyPage.setupWorkflowsDirectory({})
+  })
+
+  test('Keeps viewport settings when changing tabs', async ({
+    comfyPage,
+    comfyMouse
+  }) => {
+    // Screenshot the canvas element
+    await comfyPage.menu.topbar.saveWorkflow('Workflow A')
+    await expect(comfyPage.canvas).toHaveScreenshot('viewport-workflow-a.png')
+
+    // Save workflow as a new file, then zoom out before screen shot
+    await comfyPage.menu.topbar.saveWorkflowAs('Workflow B')
+    await comfyMouse.move(comfyPage.emptySpace)
+    for (let i = 0; i < 4; i++) {
+      await comfyMouse.wheel(0, 60)
+    }
+    await expect(comfyPage.canvas).toHaveScreenshot('viewport-workflow-b.png')
+
+    const tabA = comfyPage.menu.topbar.getWorkflowTab('Workflow A')
+    const tabB = comfyPage.menu.topbar.getWorkflowTab('Workflow B')
+
+    // Go back to Workflow A
+    await tabA.click()
+    await comfyPage.nextFrame()
+    await expect(comfyPage.canvas).toHaveScreenshot('viewport-workflow-a.png')
+
+    // And back to Workflow B
+    await tabB.click()
+    await comfyPage.nextFrame()
+    await expect(comfyPage.canvas).toHaveScreenshot('viewport-workflow-b.png')
+  })
+})