diff --git a/src/common/InputHandler.test.ts b/src/common/InputHandler.test.ts
index 20544e9d4..f9da81a25 100644
--- a/src/common/InputHandler.test.ts
+++ b/src/common/InputHandler.test.ts
@@ -11,7 +11,7 @@ import { CellData } from 'common/buffer/CellData';
 import { Attributes, BgFlags, UnderlineStyle } from 'common/buffer/Constants';
 import { AttributeData, ExtendedAttrs } from 'common/buffer/AttributeData';
 import { Params } from 'common/parser/Params';
-import { MockCoreService, MockBufferService, MockOptionsService, MockLogService, MockMouseStateService, MockCharsetService, MockUnicodeService, MockOscLinkService } from 'common/TestUtils.test';
+import { MockCoreService, MockBufferService, MockOptionsService, MockLogService, MockMouseStateService, MockCharsetService, MockUnicodeService, MockOscLinkService, extendedAttributes } from 'common/TestUtils.test';
 import { IBufferService, ICoreService, type IOscLinkService } from 'common/services/Services';
 import { DEFAULT_OPTIONS } from 'common/services/OptionsService';
 import { clone } from 'common/Clone';
@@ -2002,15 +2002,15 @@ describe('InputHandler', () => {
 
       // eAttrs in buffer pos 0 and 1 should be the same object
       assert.equal(
-        (bufferService.buffer!.lines.get(0)! as any)._extendedAttrs[0],
-        (bufferService.buffer!.lines.get(0)! as any)._extendedAttrs[1]
+        extendedAttributes(bufferService.buffer!.lines.get(0)!, 0),
+        extendedAttributes(bufferService.buffer!.lines.get(0)!, 1)
       );
       // should not have written eAttr for pos 2 in the buffer
-      assert.equal((bufferService.buffer!.lines.get(0)! as any)._extendedAttrs[2], undefined);
+      assert.equal(extendedAttributes(bufferService.buffer!.lines.get(0)!, 2), undefined);
       // eAttrs in buffer pos 1 and pos 3 must be different objs
       assert.notEqual(
-        (bufferService.buffer!.lines.get(0)! as any)._extendedAttrs[1],
-        (bufferService.buffer!.lines.get(0)! as any)._extendedAttrs[3]
+        extendedAttributes(bufferService.buffer!.lines.get(0)!, 1),
+        extendedAttributes(bufferService.buffer!.lines.get(0)!, 3)
       );
     });
   });
diff --git a/src/common/TestUtils.test.ts b/src/common/TestUtils.test.ts
index 0884a4ab4..5940fa659 100644
--- a/src/common/TestUtils.test.ts
+++ b/src/common/TestUtils.test.ts
@@ -9,7 +9,7 @@ import { clone } from 'common/Clone';
 import { DEFAULT_OPTIONS } from 'common/services/OptionsService';
 import { IBufferSet, IBuffer } from 'common/buffer/Types';
 import { BufferSet } from 'common/buffer/BufferSet';
-import { IDecPrivateModes, ICoreMouseEvent, CoreMouseEventType, ICharset, IModes, IAttributeData, IOscLinkData, IDisposable } from 'common/Types';
+import { IDecPrivateModes, ICoreMouseEvent, CoreMouseEventType, ICharset, IModes, IAttributeData, IOscLinkData, IDisposable, IBufferLine, IExtendedAttrs } from 'common/Types';
 import { UnicodeV6 } from 'common/input/UnicodeV6';
 import { IDecorationOptions, IDecoration } from '@xterm/xterm';
 import { Emitter, type IEvent } from 'common/Event';
@@ -20,6 +20,12 @@ export function createCellData(attr: number, char: string, width: number): CellD
   return CellData.fromCharData([attr, char, width, char.length === 0 ? 0 : char.charCodeAt(0)]);
 }
 
+export function extendedAttributes(line: IBufferLine, index: number): IExtendedAttrs | undefined {
+  const cell = new CellData();
+  line.loadCell(index, cell);
+  return cell.hasExtendedAttrs() !== 0 ? cell.extended : undefined;
+}
+
 export const NULL_CELL_DATA = Object.freeze(createCellData(DEFAULT_ATTR, NULL_CELL_CHAR, NULL_CELL_WIDTH));
 
 export class MockBufferService implements IBufferService {
diff --git a/src/common/buffer/BufferLine.test.ts b/src/common/buffer/BufferLine.test.ts
index b1c554781..dce68ebbf 100644
--- a/src/common/buffer/BufferLine.test.ts
+++ b/src/common/buffer/BufferLine.test.ts
@@ -5,10 +5,10 @@
 import { NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE, DEFAULT_ATTR, Content, UnderlineStyle, BgFlags, Attributes, FgFlags } from 'common/buffer/Constants';
 import { BufferLine } from 'common/buffer//BufferLine';
 import { CellData } from 'common/buffer/CellData';
-import { CharData, IBufferLine, IExtendedAttrs } from '../Types';
+import { CharData, IBufferLine } from '../Types';
 import { assert } from 'chai';
 import { AttributeData } from 'common/buffer/AttributeData';
-import { createCellData, NULL_CELL_DATA } from 'common/TestUtils.test';
+import { createCellData, NULL_CELL_DATA, extendedAttributes } from 'common/TestUtils.test';
 
 
 class TestBufferLine extends BufferLine {
@@ -25,12 +25,6 @@ class TestBufferLine extends BufferLine {
   }
 }
 
-function extendedAttributes(line: IBufferLine, index: number): IExtendedAttrs | undefined {
-  const cell = new CellData();
-  line.loadCell(index, cell);
-  return cell.hasExtendedAttrs() !== 0 ? cell.extended : undefined;
-}
-
 describe('AttributeData', () => {
   describe('extended attributes', () => {
     it('hasExtendedAttrs', () => {