ComboBoxElement.getOptions() may return empty array if the values are still being loaded

[mvysny]

combobox-testBench 23.6.0

ComboBoxElement.getOptions() may return empty array if the values are still being loaded. Solution is to wait until Combo is ready.

Fix:

    /**
     * @return true if ComboBox is still loading items and populating its dropdown.
     */
    public boolean isLoading() {
        return getPropertyBoolean("loading");
    }

    /**
     * Wait until ComboBox is finished populating its dropdown.
     */
    public void waitWhileLoading() {
        while (isLoading()) {
            try {
                Thread.sleep(200);
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
        }
    }

    @Override
    public List<String> getOptions() {
        // wait until the ComboBox dropdown is populated. Otherwise, we'll get an empty list of options.
        waitWhileLoading();
        return super.getOptions();
    }

[Artur-]

Can't reproduce this as getOptions() calls openPopup() and that seems to wait for items to appear

[mvysny]

In the sources of openPopup() I am seeing, in testbench 23.6.0, I am not seeing any wait for items - perhaps it has been fixed in later TestBench?

    public void openPopup() {
        callFunction("open");
    }

[TatuLund]

There is no difference in the Vaadin 24 or 25

https://github.com/vaadin/flow-components/blob/main/vaadin-combo-box-flow-parent/vaadin-combo-box-testbench/src/main/java/com/vaadin/flow/component/combobox/testbench/ComboBoxElement.java#L110

Without the wait the method will be flake. When server responds fast it works. But if your application under test is actually fetching data using lazy callback from containerized data base, there will be enough lag to make it fail.

One solution is to have in openPopup like

    public void openPopup() {
        callFunction("open");
        waitUntil(driver -> !getPropertyBoolean("loading"));
    }

But it could lead to excessive waiting in some cases. Thus alternative is

    public List<String> getOptions() {
        // wait until the ComboBox dropdown is populated. Otherwise, we'll get an empty list of options.
        waitUntil(driver -> !getPropertyBoolean("loading"));
        return (List<String>) executeScript("var combobox=arguments[0];" //
                + "return combobox.filteredItems.map(function(item) { return combobox._getItemLabel(item);});",
                this);
    }