✅ (VirtualizedList) add broken test case based on issue example

This test case is based on this issue: #33529
facebook · Apr 20, 2022 · 2265f04 · 2265f04
1 parent a129595
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diff --git a/Libraries/Lists/__tests__/VirtualizedList-test.js b/Libraries/Lists/__tests__/VirtualizedList-test.js
@@ -928,6 +928,55 @@ it('adjusts render area with non-zero initialScrollIndex after scrolled', () =>
   expect(component).toMatchSnapshot();
 });
 
+it('renders new items when data is updated with non-zero initialScrollIndex', () => {
+  const items = generateItems(2);
+  const ITEM_HEIGHT = 10;
+
+  let component;
+  ReactTestRenderer.act(() => {
+    component = ReactTestRenderer.create(
+      <VirtualizedList
+        initialNumToRender={5}
+        initialScrollIndex={1}
+        windowSize={10}
+        maxToRenderPerBatch={10}
+        {...baseItemProps(items)}
+        {...fixedHeightItemLayoutProps(ITEM_HEIGHT)}
+      />,
+    );
+  });
+
+  ReactTestRenderer.act(() => {
+    simulateLayout(component, {
+      viewport: {width: 10, height: 50},
+      content: {width: 10, height: 200},
+    });
+    performAllBatches();
+  });
+
+  const newItems = generateItems(4);
+
+  ReactTestRenderer.act(() => {
+    component.update(
+      <VirtualizedList
+        initialNumToRender={5}
+        initialScrollIndex={1}
+        windowSize={10}
+        maxToRenderPerBatch={10}
+        {...baseItemProps(newItems)}
+        {...fixedHeightItemLayoutProps(ITEM_HEIGHT)}
+      />,
+    );
+  });
+
+  ReactTestRenderer.act(() => {
+    performAllBatches();
+  });
+
+  // We expect all the items to be rendered
+  expect(component).toMatchSnapshot();
+});
+
 it('renders initialNumToRender cells when virtualization disabled', () => {
   const items = generateItems(10);
   const ITEM_HEIGHT = 10;

diff --git a/Libraries/Lists/__tests__/__snapshots__/VirtualizedList-test.js.snap b/Libraries/Lists/__tests__/__snapshots__/VirtualizedList-test.js.snap
@@ -3250,6 +3250,68 @@ exports[`renders items before initialScrollIndex on first batch tick when virtua
 </RCTScrollView>
 `;
 
+exports[`renders new items when data is updated with non-zero initialScrollIndex 1`] = `
+<RCTScrollView
+  data={
+    Array [
+      Object {
+        "key": 0,
+      },
+      Object {
+        "key": 1,
+      },
+      Object {
+        "key": 2,
+      },
+      Object {
+        "key": 3,
+      },
+    ]
+  }
+  getItem={[Function]}
+  getItemCount={[Function]}
+  getItemLayout={[Function]}
+  initialNumToRender={5}
+  initialScrollIndex={1}
+  maxToRenderPerBatch={10}
+  onContentSizeChange={[Function]}
+  onLayout={[Function]}
+  onMomentumScrollBegin={[Function]}
+  onMomentumScrollEnd={[Function]}
+  onScroll={[Function]}
+  onScrollBeginDrag={[Function]}
+  onScrollEndDrag={[Function]}
+  renderItem={[Function]}
+  scrollEventThrottle={50}
+  stickyHeaderIndices={Array []}
+  windowSize={10}
+>
+  <View>
+    <View
+      style={null}
+    >
+      <MockCellItem
+        value={0}
+      />
+    </View>
+    <View
+      style={null}
+    >
+      <MockCellItem
+        value={1}
+      />
+    </View>
+    <View
+      style={
+        Object {
+          "height": 20,
+        }
+      }
+    />
+  </View>
+</RCTScrollView>
+`;
+
 exports[`renders no spacers up to initialScrollIndex on first render when virtualization disabled 1`] = `
 <RCTScrollView
   data={