chore(test): new screen and scenario for specialEffects: scrollToTop prop (#3934)

## Description

Adds a test scenario for the
specialEffects.repeatedTabSelection.**scrollToTop** property on tab
routes. The scenario uses three tabs with a scrollable list each,
covering all meaningful states of the property: explicitly enabled,
explicitly disabled, and absent (default platform behavior).

The scenario also validates that scrollToTop only triggers on a repeated
tap of the already-active tab - switching away and back must preserve
scroll position.

Closes:
software-mansion/react-native-screens-labs#1154

## Changes 

**test-tabs-special-effects/index.tsx**
New test screen component with three tabs sharing a single ScrollScreen
component.

**test-tabs-special-effects/scenario.md**
Manual test scenario with four sections: scrollToTop: true, scrollToTop:
false, no specialEffects (default), and a switching-away-and-back case
that verifies scroll position is preserved on non-repeated tab
navigation.

**single-feature-tests/tabs/index.ts**
Registered TestTabsSpecialEffects in the tabs scenario group so the
screen is reachable from the test navigator.

## Test demo


https://github.com/user-attachments/assets/0047ac91-0fd3-4e86-8923-5951616a6399

---------

Co-authored-by: Krzysztof Ligarski <63918941+kligarski@users.noreply.github.com>

Author: LKuchno

apps/src/tests/single-feature-tests/tabs/index.ts

@@ -14,6 +14,7 @@ import TestTabsPreventNativeSelection from './test-tabs-prevent-native-selection
 import TestTabsStaleStateUpdateRejection from './test-tabs-stale-update-rejection';
 import TestTabsTabBarMinimizeBehavior from './test-tabs-tab-bar-minimize-behavior-ios';
 import TestTabsTabBarControllerMode from './test-tabs-tab-bar-controller-mode-ios';
+import TestTabsSpecialEffectsScrollToTop from './test-tabs-special-effects-scroll-to-top';
 
 const scenarios = {
   BottomAccessoryScenario,
@@ -30,6 +31,7 @@ const scenarios = {
   TestTabsStaleStateUpdateRejection,
   TestTabsTabBarMinimizeBehavior,
   TestTabsTabBarControllerMode,
+  TestTabsSpecialEffectsScrollToTop,
 };
 
 const TabsScenarioGroup: ScenarioGroup<keyof typeof scenarios> = {

apps/src/tests/single-feature-tests/tabs/test-tabs-special-effects-scroll-to-top/index.tsx

@@ -0,0 +1,102 @@
+import React from 'react';
+import { ScrollView, StyleSheet, Text } from 'react-native';
+import type { ScenarioDescription } from '@apps/tests/shared/helpers';
+import { createScenario } from '@apps/tests/shared/helpers';
+import {
+  TabsContainer,
+  type TabRouteConfig,
+  DEFAULT_TAB_ROUTE_OPTIONS,
+} from '@apps/shared/gamma/containers/tabs';
+
+const scenarioDescription: ScenarioDescription = {
+  name: 'Tabs scrollToTop special effect',
+  key: 'test-tabs-special-effects-scroll-to-top',
+  details:
+    'Test settings of scrollToTop specialEffect.',
+  platforms: ['ios', 'android'],
+};
+
+export function ScrollScreen() {
+  return (
+    <ScrollView>
+      <Text style={styles.hint}>Scroll Screen — scroll down or re-tap the tab.</Text>
+      {Array.from({ length: 50 }, (_, i) => (
+        <Text key={i} style={styles.item}>
+          Item {i + 1}
+        </Text>
+      ))}
+    </ScrollView>
+  );
+}
+
+const TAB_CONFIGS: TabRouteConfig[] = [
+  {
+    name: 'Tab1',
+    Component: ScrollScreen,
+    options: {
+      ...DEFAULT_TAB_ROUTE_OPTIONS,
+      title: 'Tab1',
+      specialEffects: {
+        repeatedTabSelection: {
+          scrollToTop: true,
+        },
+      },
+    },
+  },
+  {
+    name: 'Tab2',
+    Component: ScrollScreen,
+    options: {
+      ...DEFAULT_TAB_ROUTE_OPTIONS,
+      title: 'Tab2',
+      specialEffects: {
+        repeatedTabSelection: {
+          scrollToTop: false
+        },
+      },
+    },
+  },
+  {
+    name: 'Tab3',
+    Component: ScrollScreen,
+    options: {
+      ...DEFAULT_TAB_ROUTE_OPTIONS,
+      title: 'Tab3',
+    },
+  },
+];
+
+export function App() {
+  return <TabsContainer routeConfigs={TAB_CONFIGS} />;
+}
+
+export default createScenario(App, scenarioDescription);
+
+const styles = StyleSheet.create({
+  config: {
+    padding: 40,
+  },
+  centered: {
+    flex: 1,
+    alignItems: 'center',
+    justifyContent: 'center',
+    gap: 16,
+  },
+  subtitle: {
+    textAlign: 'center',
+    color: '#666',
+  },
+  switch: {
+    marginTop: 20,
+    marginBottom: 15,
+  },
+  hint: {
+    padding: 16,
+    color: '#666',
+  },
+  item: {
+    padding: 12,
+    borderBottomWidth: 1,
+    borderColor: '#eee',
+  },
+});

apps/src/tests/single-feature-tests/tabs/test-tabs-special-effects-scroll-to-top/scenario.md

@@ -0,0 +1,89 @@
+# Test Scenario: specialEffects - scrollToTop
+
+## Details
+
+**Description:** This test scenario validates the `specialEffects.repeatedTabSelection.scrollToTop`
+property on tab routes. It verifies that re-tapping an already-active
+tab scrolls a scrollable screen back to the top when the property is enabled, and
+that there is no scroll-to-top behavior when it is disabled or absent.
+
+**OS test creation version:** iOS: 18.4 and 26.2, Android: 16.0 (Baklava).
+
+## E2E test
+
+Other: ongoing research.
+
+## Prerequisites
+
+- iOS device or simulator
+- Android emulator
+
+## Note (Optional)
+
+Tab1 has `scrollToTop: true`, Tab2 has `scrollToTop: false`, and Tab3 has no
+`specialEffects` configured (default behavior). All three tabs display a scrollable
+list of 50 items.
+
+## Steps
+
+### scrollToTop: true
+
+1. Launch the app and navigate to the screen **Tabs specialEffects**.
+
+- [ ] Expected: Three tabs (Tab1, Tab2, Tab3) are visible in the tab bar.
+Tab1 is active and displays a scrollable list of items.
+
+2. Scroll down several items in Tab1.
+
+- [ ] Expected: The list scrolls down; items above the fold are no longer visible.
+
+3. Re-tap Tab1 (the already-active tab).
+
+- [ ] Expected: The list animates back to the top of the scroll position
+(item 1 is visible).
+
+### scrollToTop: false
+
+4. Tap Tab2.
+
+- [ ] Expected: Tab2 becomes active and displays a scrollable list of items.
+
+5. Scroll down several items in Tab2.
+
+- [ ] Expected: The list scrolls down; items above the fold are no longer visible.
+
+6. Re-tap Tab2 (the already-active tab).
+
+- [ ] Expected: The list does **not** scroll back to the top; scroll position is
+preserved.
+
+### no specialEffects (default)
+
+7. Tap Tab3.
+
+- [ ] Expected: Tab3 becomes active and displays a scrollable list of items.
+
+8. Scroll down several items in Tab3.
+
+- [ ] Expected: The list scrolls down; items above the fold are no longer visible.
+
+9. Re-tap Tab3 (the already-active tab).
+
+- [ ] Expected: Observe and note the default behavior - back to the top of the
+scroll position (item 1 is visible).
+
+### scrollToTop: true — switching away and back (not a repeated tap)
+
+10. Tap Tab1 and scroll down several items.
+
+- [ ] Expected: Tab1 becomes active. The list scrolls down;
+items above the fold are no longer visible.
+
+11. Tap Tab3 to switch away from Tab1.
+
+- [ ] Expected: Tab3 becomes active and displays its scrollable list.
+
+12. Tap Tab1 again.
+
+- [ ] Expected: Tab1 becomes active and the scroll position is **preserved** -
+the list does not scroll back to the top.