From 81abd306bbcde3bea255c835271b4f0675f67d4c Mon Sep 17 00:00:00 2001
From: Zeya Peng <zeyap@meta.com>
Date: Wed, 13 Aug 2025 17:36:06 -0700
Subject: [PATCH] test FlatList props: data, renderItem, horizontal, inverted,
 scrollEnabled (#53186)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53186

## Changelog:

[Internal] [Changed] - test FlatList props: data, renderItem, horizontal, inverted, scrollEnabled

uncovered one bug in `getDebugProps()`

Reviewed By: rshest

Differential Revision: D79895309

fbshipit-source-id: 0644cf9877620a7787ee085a8e934f462e5de3ef
---
 .../Lists/__tests__/FlatList-itest.js         | 148 ++++++++++++++++++
 .../scrollview/BaseScrollViewProps.cpp        |   2 +-
 2 files changed, 149 insertions(+), 1 deletion(-)
 create mode 100644 packages/react-native/Libraries/Lists/__tests__/FlatList-itest.js

diff --git a/packages/react-native/Libraries/Lists/__tests__/FlatList-itest.js b/packages/react-native/Libraries/Lists/__tests__/FlatList-itest.js
new file mode 100644
index 00000000000..e24f8011639
--- /dev/null
+++ b/packages/react-native/Libraries/Lists/__tests__/FlatList-itest.js
@@ -0,0 +1,148 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow strict-local
+ * @format
+ */
+
+import '@react-native/fantom/src/setUpDefaultReactNativeEnvironment';
+
+import * as Fantom from '@react-native/fantom';
+import * as React from 'react';
+import {FlatList, Text} from 'react-native';
+
+describe('<FlatList>', () => {
+  describe('props', () => {
+    describe('data & renderItem', () => {
+      const root = Fantom.createRoot();
+      it('List is rendered as expected', () => {
+        Fantom.runTask(() => {
+          root.render(
+            <FlatList
+              data={[
+                {title: 'Title Text', key: 'item1'},
+                {title: 'Title Text 2', key: 'item2'},
+              ]}
+              renderItem={({item, separators}) => <Text>{item.title}</Text>}
+            />,
+          );
+        });
+
+        expect(
+          JSON.stringify(root.getRenderedOutput({props: []}).toJSX()),
+        ).toEqual(
+          JSON.stringify(
+            <rn-scrollView>
+              <rn-view>
+                <rn-paragraph key="0">Title Text</rn-paragraph>
+                <rn-paragraph key="1">Title Text 2</rn-paragraph>
+              </rn-view>
+            </rn-scrollView>,
+          ),
+        );
+      });
+    });
+
+    describe('inverted', () => {
+      it('changes prop isInvertedVirtualizedList which gets propagated to mounting layer', () => {
+        const root = Fantom.createRoot();
+        Fantom.runTask(() => {
+          root.render(<FlatList data={null} inverted={true} />);
+        });
+
+        expect(
+          root
+            .getRenderedOutput({
+              props: ['inverted', 'isInvertedVirtualizedList'],
+            })
+            .toJSX(),
+        ).toEqual(
+          <rn-scrollView isInvertedVirtualizedList="true">
+            <rn-view />
+          </rn-scrollView>,
+        );
+      });
+
+      it('default value is false', () => {
+        const root = Fantom.createRoot();
+        Fantom.runTask(() => {
+          root.render(<FlatList data={null} inverted={false} />);
+        });
+
+        expect(
+          root
+            .getRenderedOutput({
+              props: ['inverted', 'isInvertedVirtualizedList'],
+            })
+            .toJSX(),
+        ).toEqual(
+          <rn-scrollView>
+            <rn-view />
+          </rn-scrollView>,
+        );
+      });
+    });
+  });
+
+  describe('props inherited from ScrollView', () => {
+    describe('horizontal', () => {
+      const root = Fantom.createRoot();
+      it('is propagated to the mounting layer', () => {
+        Fantom.runTask(() => {
+          root.render(<FlatList data={null} horizontal={true} />);
+        });
+
+        expect(root.getRenderedOutput({props: ['horizontal']}).toJSX()).toEqual(
+          <rn-scrollView horizontal="true">
+            <rn-androidHorizontalScrollContentView />
+          </rn-scrollView>,
+        );
+      });
+
+      it('default value is false', () => {
+        Fantom.runTask(() => {
+          root.render(<FlatList data={null} horizontal={false} />);
+        });
+
+        expect(root.getRenderedOutput({props: ['horizontal']}).toJSX()).toEqual(
+          <rn-scrollView>
+            <rn-view />
+          </rn-scrollView>,
+        );
+      });
+    });
+
+    describe('scrollEnabled', () => {
+      const root = Fantom.createRoot();
+      it('default value is true', () => {
+        Fantom.runTask(() => {
+          root.render(<FlatList data={null} scrollEnabled={true} />);
+        });
+
+        expect(
+          root.getRenderedOutput({props: ['scrollEnabled']}).toJSX(),
+        ).toEqual(
+          <rn-scrollView>
+            <rn-view />
+          </rn-scrollView>,
+        );
+      });
+      it('is propagated to the mounting layer', () => {
+        Fantom.runTask(() => {
+          root.render(<FlatList data={null} scrollEnabled={false} />);
+        });
+
+        expect(
+          root.getRenderedOutput({props: ['scrollEnabled']}).toJSX(),
+        ).toEqual(
+          <rn-scrollView scrollEnabled="false">
+            <rn-view />
+          </rn-scrollView>,
+        );
+      });
+    });
+  });
+});
diff --git a/packages/react-native/ReactCommon/react/renderer/components/scrollview/BaseScrollViewProps.cpp b/packages/react-native/ReactCommon/react/renderer/components/scrollview/BaseScrollViewProps.cpp
index a62c9f1bc99..a683cb87f82 100644
--- a/packages/react-native/ReactCommon/react/renderer/components/scrollview/BaseScrollViewProps.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/components/scrollview/BaseScrollViewProps.cpp
@@ -558,7 +558,7 @@ SharedDebugStringConvertibleList BaseScrollViewProps::getDebugProps() const {
               "snapToEnd", snapToEnd, defaultScrollViewProps.snapToEnd),
           debugStringConvertibleItem(
               "isInvertedVirtualizedList",
-              snapToEnd,
+              isInvertedVirtualizedList,
               defaultScrollViewProps.isInvertedVirtualizedList)};
 }
 #endif