Add virtual list provider coverage

continue.md

@@ -42,9 +42,14 @@ Actualizacion 2026-05-15:
     date/time y commit solo cuando los segmentos renderizados estan completos.
   - Correccion DateField: el announcer se inicializa con `$effect` en vez de
     `onMount()` dentro de la clase.
+  - Cobertura nueva para VirtualList: cálculo de ventana, `scrollToIndex` y
+    compensación anti-jump.
+  - Correccion VirtualList: la compensación de mediciones dinámicas sobre
+    viewports internos pasa por `ActiveDom.scrollTo(...)` y usa
+    `scrollOffset + delta` como fuente reactiva.
   - Validado por fase:
     - `npm run check` -> 0 errores, 0 warnings.
-    - `npm run test` -> 184 archivos, 2080 tests OK.
+    - `npm run test` -> 185 archivos, 2083 tests OK.
     - tests focales de Select/Popover/Toast/RangeCalendar -> 11 tests OK.
     - tests focales Dialog/Drawer/Popover/Select -> 10 tests OK.
     - `command-provider.svelte.test.ts` -> 2 tests OK.
@@ -57,6 +62,7 @@ Actualizacion 2026-05-15:
     - `time-field-provider.svelte.test.ts` -> 3 tests OK.
     - `date-range-field-provider.svelte.test.ts` -> 3 tests OK.
     - `date-field-provider.svelte.test.ts` -> 7 tests OK.
+    - `virtual-list-provider.svelte.test.ts` -> 3 tests OK.
     - guardia `rg "from './.*provider\\.svelte'" src/uix/soma/components -g 'exports.ts'`
       -> solo queda `select/components/select-provider.svelte`, que es wrapper
       publico, no runtime provider.

src/uix/soma/SOMA_ARCHITECTURE.md

@@ -478,11 +478,13 @@ Los tests por componente estan creciendo desde las piezas de mayor riesgo. A
   completos.
 - `date-range-field/date-range-field-provider.svelte.test.ts` — validación de
   orden/min/max, validación custom y foco de label via `ActiveDom`.
+- `virtual-list/virtual-list-provider.svelte.test.ts` — cálculo de ventana,
+  `scrollToIndex` y compensación anti-jump via `ActiveDom`.
 
 Pendiente: seguir ampliando cobertura por familias de alto riesgo fuera del
-bloque fecha/hora. `table-core`, `form-core` y el scorer de Command ya no viven
+bloque fecha/hora/virtualización. `table-core`, `form-core` y el scorer de
-dentro de Soma: se consumen desde `$libs/datagrid`, `$libs/forms` y
+Command ya no viven dentro de Soma: se consumen desde `$libs/datagrid`,
-`$libs/strings`.
+`$libs/forms` y `$libs/strings`.
 
 ### Convencion
 

src/uix/soma/components/virtual-list/virtual-list-provider.svelte.test.ts

@@ -0,0 +1,121 @@
+// @vitest-environment jsdom
+
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+import { createActiveDom } from '$adom';
+import { state } from '$libs/reactive';
+import type { Morfo } from '$uix/morfo';
+import { Soma } from '$soma/core/soma.svelte';
+import { createSomaRuntime, type SomaRuntimeSources } from '$soma/runtime.svelte';
+import type { Orientation } from '../../types';
+
+import { VirtualListProvider } from './virtual-list-provider.svelte';
+
+function withEffectRoot<T>(fn: () => T): { result: T; cleanup: () => void } {
+	let result!: T;
+	const cleanup = $effect.root(() => {
+		result = fn();
+	});
+	return { result, cleanup };
+}
+
+function installSomaHarness() {
+	const dom = createActiveDom();
+	const soma = {
+		dom,
+		runtime: (morfo: Morfo, sources: Omit<SomaRuntimeSources, 'dom' | 'eventEngine'>) =>
+			createSomaRuntime(morfo, {
+				dom,
+				translate: (key) => key,
+				...sources
+			})
+	} as unknown as Soma;
+
+	vi.spyOn(Soma, 'require').mockReturnValue(soma);
+	vi.spyOn(VirtualListProvider.ctx, 'set').mockImplementation((value) => value);
+
+	return { dom };
+}
+
+function createVirtualListOpts() {
+	return {
+		id: state('virtual-list-root'),
+		ref: state<HTMLElement | null>(null),
+		count: state(10),
+		itemSize: state<number | undefined>(20),
+		estimateSize: state<(index: number) => number>(() => 20),
+		overscan: state(1),
+		orientation: state<Orientation>('vertical'),
+		getItemKey: state<(index: number) => string | number>((index) => `row-${index}`)
+	};
+}
+
+describe('VirtualListProvider', () => {
+	afterEach(() => {
+		vi.restoreAllMocks();
+		document.body.innerHTML = '';
+	});
+
+	it('computes fixed-size virtual items from viewport and overscan', () => {
+		const { dom } = installSomaHarness();
+		const opts = createVirtualListOpts();
+
+		const { result: provider, cleanup } = withEffectRoot(() => VirtualListProvider.create(opts));
+		provider.viewportSize = 100;
+		provider.scrollOffset = 50;
+
+		expect(provider.totalSize).toBe(200);
+		expect(provider.virtualItems.map((item) => item.index)).toEqual([1, 2, 3, 4, 5, 6, 7, 8]);
+		expect(provider.virtualItems[0]).toEqual({
+			index: 1,
+			start: 20,
+			size: 20,
+			key: 'row-1'
+		});
+
+		cleanup();
+		dom.dispose();
+	});
+
+	it('routes scrollToIndex through ActiveDom for internal viewports', () => {
+		const { dom } = installSomaHarness();
+		const opts = createVirtualListOpts();
+		const viewport = document.createElement('div');
+		const scrollTo = vi.spyOn(dom, 'scrollTo');
+
+		const { result: provider, cleanup } = withEffectRoot(() => VirtualListProvider.create(opts));
+		provider.viewportRef = viewport;
+		provider.viewportSize = 100;
+
+		provider.scrollToIndex(5, { align: 'center' });
+
+		expect(scrollTo).toHaveBeenCalledWith(viewport, {
+			top: 60,
+			behavior: 'auto'
+		});
+
+		cleanup();
+		dom.dispose();
+	});
+
+	it('compensates dynamic measurements above the viewport through ActiveDom', () => {
+		const { dom } = installSomaHarness();
+		const opts = createVirtualListOpts();
+		opts.itemSize.current = undefined;
+		const viewport = document.createElement('div');
+		viewport.scrollTop = 50;
+		const scrollTo = vi.spyOn(dom, 'scrollTo');
+
+		const { result: provider, cleanup } = withEffectRoot(() => VirtualListProvider.create(opts));
+		provider.viewportRef = viewport;
+		provider.viewportSize = 100;
+		provider.scrollOffset = 50;
+
+		provider.measureItem(0, 30);
+
+		expect(scrollTo).toHaveBeenCalledWith(viewport, { top: 60 });
+
+		cleanup();
+		dom.dispose();
+	});
+});

src/uix/soma/components/virtual-list/virtual-list-provider.svelte.ts

@@ -218,8 +218,10 @@ export class VirtualListProvider {
 
 		const vp = this.viewportRef;
 		if (vp) {
-			if (this.isHorizontal) vp.scrollLeft += delta;
+			this.soma.dom.scrollTo(
-			else vp.scrollTop += delta;
+				vp,
+				this.isHorizontal ? { left: this.scrollOffset + delta } : { top: this.scrollOffset + delta }
+			);
 			return;
 		}
 		// Window-scroll mode: shift document scroll by the delta.