diff --git a/src/browser/Viewport.test.ts b/src/browser/Viewport.test.ts
deleted file mode 100644
index 359a9a42c..000000000
--- a/src/browser/Viewport.test.ts
+++ /dev/null
@@ -1,161 +0,0 @@
-/**
- * Copyright (c) 2026 The xterm.js authors. All rights reserved.
- * @license MIT
- */
-
-import { assert } from 'chai';
-import jsdom = require('jsdom');
-import { Viewport } from 'browser/Viewport';
-import { MockThemeService } from 'browser/TestUtils.test';
-import { createRenderDimensions } from 'browser/renderer/shared/RendererUtils';
-import { Emitter } from 'common/Event';
-import { MockBufferService, MockCoreService, MockMouseStateService, MockOptionsService } from 'common/TestUtils.test';
-import { css } from 'common/Color';
-import type { IRenderDimensions } from 'browser/renderer/shared/Types';
-import type { ICoreBrowserService, IRenderService } from 'browser/services/Services';
-
-class TestRenderService implements IRenderService {
-  public serviceBrand: undefined;
-  private readonly _onRender = new Emitter<{ start: number, end: number }>();
-
-  public onDimensionsChange = new Emitter<IRenderDimensions>().event;
-  public onRenderedViewportChange = new Emitter<{ start: number, end: number }>().event;
-  public onRender = this._onRender.event;
-  public onRefreshRequest = new Emitter<{ start: number, end: number }>().event;
-  public dimensions: IRenderDimensions = createRenderDimensions();
-
-  constructor() {
-    this.dimensions.css.cell.height = 10;
-    this.dimensions.css.canvas.height = 100;
-  }
-
-  public fireRender(): void {
-    this._onRender.fire({ start: 0, end: 0 });
-  }
-
-  public addRefreshCallback(callback: FrameRequestCallback): number {
-    callback(0);
-    return 1;
-  }
-  public refreshRows(start: number, end: number, sync?: boolean): void { }
-  public clearTextureAtlas(): void { }
-  public resize(cols: number, rows: number): void { }
-  public hasRenderer(): boolean { return true; }
-  public setRenderer(renderer: any): void { }
-  public handleDevicePixelRatioChange(): void { }
-  public handleResize(cols: number, rows: number): void { }
-  public handleCharSizeChanged(): void { }
-  public handleBlur(): void { }
-  public handleFocus(): void { }
-  public handleSelectionChanged(start: [number, number] | undefined, end: [number, number] | undefined, columnSelectMode: boolean): void { }
-  public handleCursorMove(): void { }
-  public clear(): void { }
-  public dispose(): void { }
-}
-
-describe('Viewport', () => {
-  function setup(): {
-    viewport: Viewport;
-    renderService: TestRenderService;
-    coreService: MockCoreService;
-    dispose: () => void;
-  } {
-    const dom = new jsdom.JSDOM();
-    const previousWindow = (globalThis as any).window;
-    const previousDocument = (globalThis as any).document;
-    (globalThis as any).window = dom.window;
-    (globalThis as any).document = dom.window.document;
-
-    const element = dom.window.document.createElement('div');
-    const screenElement = dom.window.document.createElement('div');
-
-    const optionsService = new MockOptionsService();
-    const bufferService = new MockBufferService(80, 5, optionsService);
-    const coreBrowserService: ICoreBrowserService = {
-      serviceBrand: undefined,
-      isFocused: true,
-      onDprChange: new Emitter<number>().event,
-      onWindowChange: new Emitter<Window & typeof globalThis>().event,
-      window: dom.window as unknown as Window & typeof globalThis,
-      mainDocument: dom.window.document,
-      dpr: 1
-    };
-
-    const coreService = new MockCoreService();
-    const mouseStateService = new MockMouseStateService();
-    const themeService = new MockThemeService();
-    (themeService.colors as any).scrollbarSliderBackground = css.toColor('#333333');
-    (themeService.colors as any).scrollbarSliderHoverBackground = css.toColor('#444444');
-    (themeService.colors as any).scrollbarSliderActiveBackground = css.toColor('#555555');
-    const renderService = new TestRenderService();
-
-    const viewport = new Viewport(
-      element,
-      screenElement,
-      bufferService,
-      coreBrowserService,
-      coreService,
-      mouseStateService,
-      themeService,
-      optionsService,
-      renderService
-    );
-
-    return {
-      viewport,
-      renderService,
-      coreService,
-      dispose: () => {
-        viewport.dispose();
-        dom.window.close();
-        (globalThis as any).window = previousWindow;
-        (globalThis as any).document = previousDocument;
-      }
-    };
-  }
-
-  it('should defer DOM sync during synchronized output and flush on render', () => {
-    const test = setup();
-    let dimSyncCalls = 0;
-    let posSyncCalls = 0;
-
-    const scrollableElement = (test.viewport as any)._scrollableElement;
-    scrollableElement.setScrollDimensions = () => { dimSyncCalls++; };
-    scrollableElement.setScrollPosition = () => { posSyncCalls++; };
-
-    test.coreService.decPrivateModes.synchronizedOutput = true;
-    (test.viewport as any)._sync(3);
-
-    assert.equal(dimSyncCalls, 0);
-    assert.equal(posSyncCalls, 0);
-    assert.equal((test.viewport as any)._needsSyncOnRender, true);
-
-    test.coreService.decPrivateModes.synchronizedOutput = false;
-    test.renderService.fireRender();
-
-    assert.equal(dimSyncCalls, 1);
-    assert.equal(posSyncCalls, 1);
-    assert.equal((test.viewport as any)._needsSyncOnRender, false);
-
-    test.dispose();
-  });
-
-  it('should sync DOM immediately when synchronized output is disabled', () => {
-    const test = setup();
-    let dimSyncCalls = 0;
-    let posSyncCalls = 0;
-
-    const scrollableElement = (test.viewport as any)._scrollableElement;
-    scrollableElement.setScrollDimensions = () => { dimSyncCalls++; };
-    scrollableElement.setScrollPosition = () => { posSyncCalls++; };
-
-    test.coreService.decPrivateModes.synchronizedOutput = false;
-    (test.viewport as any)._sync(2);
-
-    assert.equal(dimSyncCalls, 1);
-    assert.equal(posSyncCalls, 1);
-    assert.equal((test.viewport as any)._needsSyncOnRender, false);
-
-    test.dispose();
-  });
-});