Jest snapshot testing of FlatList renderItem

Question

I have a wrapper for Flatlist called FlatListShadow but for this post FlatListShadow and FlatList is the same thing

I need to test the renderItem function in FlatListShadow which looks like this

renderItem={({ item }) => (
      <Device
        title={item.deviceName}
        platform={item.platform}
        updatedAt={item.updatedAt}
        status={item.status}
        selectDevice={() => selectDevice(item.deviceId)}
        isSelected={selectedDeviceIdList.includes(item.deviceId)}
      />
    )}

Unfortuanately in the snapshot it only gives this information

renderItem={[Function]}

Answer 1

If you are using jest :

describe('EasyToUseSection', () => {
  it.only('flatlist should return renderItem correctly', () => {
    const itemData = {
      name: 'Name',
      desc: 'Description',
    };
   const { getByTestId } = renderComponent();
   expect(getByTestId('flatlist')).toBeDefined();
   const element = getByTestId('flatlist').props.renderItem(itemData);
   expect(element.props.data).toStrictEqual(itemData);
   expect(element.type).toBe(Device);
   });
});

This way the data that is sent is checked and also the component rendered type can be checked