test: add test for Flow issue #19006

[tepi]

Test for vaadin/flow#19006

[vursen]

I'm inclined to recommend this alternative test setup – it reproduces the issue in a way that is less likely to be affected by future refactorings:

1. Expand All
2. Scroll to 0-250
3. Scroll to start

TreeGrid grid = new TreeGrid<String>();
grid.setPageSize(10);
grid.addHierarchyColumn(String::toString).setHeader("Item");

var data = new TreeData<String>();

for (int i = 0; i < 500; i++) {
    data.addRootItems("Item-" + i);
}

for (int i = 0; i < 500; i++) {
    data.addItems("Item-0", "Item-0-" + i);
}

for (int j = 0; j < 500; j++) {
    data.addItems("Item-0-0", "Item-0-0-" + j);
}

grid.setDataProvider(new TreeDataProvider<>(data));

add(grid);

add(new NativeButton("Expand all",
        e -> grid.expandRecursively(data.getRootItems(), 1)));

add(new NativeButton("Scroll to 0-250",
        e -> grid.scrollToIndex(0, 250)));

add(new NativeButton("Scroll to start",
        e -> grid.scrollToStart()));

[tepi]

Modified the test as recommended. Also added id checks in every step of the test.

[ugur-vaadin]

LGTM apart from the unused imports.

[sonarcloud]

Quality Gate passed

Issues
4 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud