package com.vaadin.ui; import static org.junit.Assert.assertArrayEquals; import java.util.ArrayList; import java.util.List; import org.junit.Test; import com.vaadin.server.ServerRpcManager; import com.vaadin.shared.data.selection.SelectionServerRpc; import com.vaadin.tests.util.MockUI; public class ComboBoxTest { private List eventValues = new ArrayList<>(); @Test public void testResetValue() { ComboBox comboBox = new ComboBox<>(); comboBox.setItems("one", "two"); // Reset value whenever it changes (in a real case, this listener would // do something with the selected value before discarding it) comboBox.addValueChangeListener(event -> { eventValues.add(event.getValue()); comboBox.setValue(null); }); // "Attach" the component and initialize diffstate new MockUI().setContent(comboBox); // Generate initial data comboBox.getDataCommunicator().beforeClientResponse(true); ComponentTest.syncToClient(comboBox); // Emulate selection of "one" String oneKey = comboBox.getDataCommunicator().getKeyMapper() .key("one"); ServerRpcManager.getRpcProxy(comboBox, SelectionServerRpc.class) .select(oneKey); assertArrayEquals("Unexpected values from selection events", new Object[] { "one", null }, eventValues.toArray()); ComponentTest.assertEncodedStateProperties(comboBox, "Selection change done by the listener should be sent to the client", "selectedItemKey"); } }