diff --git a/apps/web/src/app/shared/grid/lines-grid.spec.ts b/apps/web/src/app/shared/grid/lines-grid.spec.ts
index 364f169..44daeaf 100644
--- a/apps/web/src/app/shared/grid/lines-grid.spec.ts
+++ b/apps/web/src/app/shared/grid/lines-grid.spec.ts
@@ -3,6 +3,7 @@ import { HttpTestingController, provideHttpClientTesting } from '@angular/common
 import { Component, signal } from '@angular/core';
 import { type ComponentFixture, TestBed } from '@angular/core/testing';
 import { beforeEach, describe, expect, it } from 'vitest';
+import { AccountCodesService } from '../../core/sl/account-codes';
 import { ITEMS_MULTI_ADD, LINE_COLUMNS, newDocumentLine, recalcLine } from '../../features/documents/line-columns';
 
 /** Las ocho columnas básicas de una línea (las posiciones que usan estos tests). */
@@ -614,3 +615,50 @@ describe('LinesGrid: dónde va la columna de lotes y series', () => {
     expect(el.querySelector('input[data-r="0"][data-c="2"]')).toBeTruthy();
   });
 });
+
+describe('LinesGrid: celdas de cuenta', () => {
+  let fixture: ComponentFixture<Host>;
+  let ctrl: HttpTestingController;
+  let el: HTMLElement;
+  const tick = async () => {
+    fixture.detectChanges();
+    await new Promise((r) => setTimeout(r));
+    fixture.detectChanges();
+  };
+  const cell = () => el.querySelector<HTMLInputElement>('input[data-r="0"][data-c="1"]')!;
+
+  beforeEach(async () => {
+    await TestBed.configureTestingModule({
+      imports: [Host],
+      providers: [provideHttpClient(), provideHttpClientTesting()],
+    }).compileComponents();
+    ctrl = TestBed.inject(HttpTestingController);
+    TestBed.inject(AccountCodesService); // la app lo instancia en su marco principal
+    fixture = TestBed.createComponent(Host);
+    el = fixture.nativeElement;
+    fixture.componentInstance.columns = [LINE_COLUMNS.item, LINE_COLUMNS.account];
+  });
+
+  it('una línea con la cuenta interna pide su código con formato y lo muestra', async () => {
+    fixture.componentInstance.lines.set([{ ItemCode: 'S1', AccountCode: '_SYS00000002407' }]);
+    await tick();
+    const req = ctrl.expectOne((r) => r.url === '/api/sl/ChartOfAccounts' && r.params.get('$filter') === "Code eq '_SYS00000002407'");
+    req.flush({ value: [{ Code: '_SYS00000002407', FormatCode: '1071111010' }] });
+    await tick();
+    expect(cell().value).toBe('1071111010');
+    expect(fixture.componentInstance.lines()[0]['AccountCode']).toBe('_SYS00000002407'); // lo guardado sigue siendo el interno
+  });
+
+  it('escribir el código con formato guarda el interno de la cuenta', async () => {
+    fixture.componentInstance.lines.set([{ ItemCode: 'S1' }]);
+    await tick();
+    cell().value = '1071111010';
+    cell().dispatchEvent(new Event('change'));
+    await tick();
+    const req = ctrl.expectOne((r) => r.url === '/api/sl/ChartOfAccounts' && (r.params.get('$filter') ?? '').includes("FormatCode eq '1071111010'"));
+    req.flush({ value: [{ Code: '_SYS00000002407', FormatCode: '1071111010', Name: 'Banco' }] });
+    await tick();
+    expect(fixture.componentInstance.lines()[0]['AccountCode']).toBe('_SYS00000002407');
+    expect(cell().value).toBe('1071111010');
+  });
+});