Styjun

When trying to simulate input using AssertJ's pressAndReleaseKeys() for unit testing a JComboBox in a Java Swing program, I am not seeing the expected behavior. The program will most often hang on the pressAndReleaseKeys line and then fail, or occasionally will delete all the text currently in the JComboBox being tested, causing later assertions to fail (i.e. requireSelection()). The stack trace I receive for the provided example program (see below) when it hangs is as follows:

Focus change to javax.swing.JComboBox[name='combob', selectedItem='Bean', contents=["Pork", "Beans", "Rice"], editable=true, enabled=true, visible=true, showing=true] failed focus owner: javax.swing.plaf.metal.MetalComboBoxEditor$1(javax.swing.JTextField)[name=null, text='Bean', enabled=true, visible=true, showing=true]

org.assertj.swing.exception.ActionFailedException

at org.assertj.swing.exception.ActionFailedException.actionFailure(ActionFailedException.java:33)

at org.assertj.swing.core.BasicRobot.focus(BasicRobot.java:301)

at org.assertj.swing.core.BasicRobot.focusAndWaitForFocusGain(BasicRobot.java:270)

at org.assertj.swing.driver.ComponentDriver.focusAndWaitForFocusGain(ComponentDriver.java:419)

at org.assertj.swing.driver.ComponentDriver.pressAndReleaseKeys(ComponentDriver.java:315)

at org.assertj.swing.fixture.AbstractComponentFixture.pressAndReleaseKeys(AbstractComponentFixture.java:293)

at javapractice.ComboBoxSampleTest.testMain(ComboBoxSampleTest.java:59)

I have been using FEST and am hoping to migrate my tests to AssertJ since it is being actively maintained, whereas FEST hasn't been updated for years. I used Joel Costigliola's migration from Fest to AssertJ guide, but am having trouble when simulating keyboard input by using pressAndReleaseKeys(). I am able to simulate input when using a JTextComponentFixture i.e.

window.textBox("textB").pressAndReleaseKeys(KeyEvent.VK_LEFT);

(where window is a FrameFixture, a container in both AssertJ and FEST), but I am unable to simulate input when using a JComboBoxFixture i.e.

window.comboBox("comboB").pressAndReleaseKeys(KeyEvent.VK_LEFT);

This obstacle can usually be avoided, since most "key presses" can be simulated by using enterText i.e.

window.comboBox("comboB").enterText("n"); //to press the enter key
window.comboBox("comboB").enterText("b"); //to press the backspace key

but I would like to be able to use the arrow keys, control key, and other keys where I can't simulate the key press using enterText(). Is this failure due to an issue with my environment*, an issue with the way I'm using it, or is the API itself flawed?

I tried using pressKey() and then releaseKey() as a workaround, but that doesn't work with JComboBox either, and my program instead hangs on pressKey(). That being said, I am not able to use pressKey() and releaseKey() to test a JComboBox with FEST either.

*Environment details:

Language version: java version "1.8.0_131"

Platform version (e.g. .NET 3.5; note that this isn’t always implicit from the language version, or vice versa)

Operating system: Red Hat Release 6.10 (Santiago)

IDE: Netbeans 8.0.2

Sample GUI application:

package javapractice;

import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class ComboBoxSample extends JFrame implements ItemListener
 JPanel jp;
 JComboBox jcb;
 JLabel result;
 JLabel title;
 JTextField jtc;

 public static void main(String[] args) 
 ComboBoxSample frame = new ComboBoxSample();
 

 ComboBoxSample() 
 super();
 this.setDefaultCloseOperation(EXIT_ON_CLOSE);
 this.setVisible(true);
 this.setTitle("Testing AssertJ");
 this.setLayout(new FlowLayout());
 jp = new JPanel();
 jcb = new JComboBox(new String[] "Pork", "Beans", "Rice");
 jcb.setEditable(true);
 jcb.setName("combob");
 jtc = new JTextField();
 jtc.setEditable(true);
 jtc.setPreferredSize(new Dimension(150, 25));
 jtc.setName("textb");
 title = new JLabel("Food: ");
 result = new JLabel("No food");
 jp.add(title);
 jp.add(jcb);
 jp.add(result);
 jp.add(jtc);
 this.add(jp);
 this.setLocationRelativeTo(null);
 jcb.addItemListener(this);


 this.pack();
 this.repaint(); 
 

 @Override
 public void itemStateChanged(ItemEvent e) 
 if(e.getSource() == jcb) 
 result.setText("I'm eating " + jcb.getSelectedItem());
 
 this.pack();
 

 public void cleanUp() 
 jcb = null;
 result = null;
 jtc = null;
 jp = null;
 title = null;
 

Test File for Fest:

package javapractice;

import com.sun.glass.events.KeyEvent;
import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;

/**
 * Fest imports.
 */
import org.fest.swing.edt.FailOnThreadViolationRepaintManager;
import org.fest.swing.edt.GuiActionRunner;
import org.fest.swing.edt.GuiQuery;
import org.fest.swing.fixture.FrameFixture;

public class ComboBoxSampleTest 
 private FrameFixture window;
 private ComboBoxSample frame;

 @BeforeClass
 public static void setUpClass() 
 FailOnThreadViolationRepaintManager.install();
 

 @AfterClass
 public static void tearDownClass() 

 

 @Before
 public void setUp() 
 frame = GuiActionRunner.execute(new GuiQuery<ComboBoxSample>() 
 @Override
 protected ComboBoxSample executeInEDT() 
 return new ComboBoxSample();
 
 );
 window = new FrameFixture(frame);
 window.show();
 

 @After
 public void tearDown() 
 window.cleanUp();
 frame.cleanUp();
 

 /**
 * Test of main method, of class ComboBoxSample.
 */
 @Test
 public void testMain() 
 //Delay so that we can see what's going on
 try 
 Thread.sleep(2000);
 catch (InterruptedException ie) 

 

 window.textBox("textb").enterText("hi there");
 window.textBox("textb").pressAndReleaseKeys(KeyEvent.VK_BACKSPACE);
 window.comboBox().replaceText("Bean");
 window.comboBox().pressAndReleaseKeys(KeyEvent.VK_S);
 window.comboBox().pressAndReleaseKeys(KeyEvent.VK_DOWN);
 window.comboBox().pressAndReleaseKeys(KeyEvent.VK_DOWN);
 window.comboBox().pressAndReleaseKeys(KeyEvent.VK_DOWN);
 window.comboBox().pressAndReleaseKeys(KeyEvent.VK_ENTER);
 

Test File for AssertJ:

package javapractice;

import com.sun.glass.events.KeyEvent;
import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;

/**
 * AssertJ imports.
 */
import org.assertj.swing.edt.FailOnThreadViolationRepaintManager;
import org.assertj.swing.edt.GuiActionRunner;
import org.assertj.swing.fixture.FrameFixture;

public class ComboBoxSampleTest 
 private FrameFixture window;
 private ComboBoxSample frame;

 @BeforeClass
 public static void setUpClass() 
 FailOnThreadViolationRepaintManager.install();
 

 @AfterClass
 public static void tearDownClass() 

 

 @Before
 public void setUp() 
 frame = GuiActionRunner.execute(() -> new ComboBoxSample());
 window = new FrameFixture(frame);
 window.show();
 

 @After
 public void tearDown() 
 window.cleanUp();
 frame.cleanUp();
 

 /**
 * Test of main method, of class ComboBoxSample.
 */
 @Test
 public void testMain() 
 //Delay so that we can see what's going on
 try 
 Thread.sleep(2000);
 catch (InterruptedException ie) 

 

 window.textBox("textb").enterText("hi there");
 window.textBox("textb").pressAndReleaseKeys(KeyEvent.VK_BACKSPACE);
 window.comboBox().replaceText("Bean");
 //the above line is the last one to execute
 window.comboBox().pressAndReleaseKeys(KeyEvent.VK_S);
 window.comboBox().pressAndReleaseKeys(KeyEvent.VK_DOWN);
 window.comboBox().pressAndReleaseKeys(KeyEvent.VK_DOWN);
 window.comboBox().pressAndReleaseKeys(KeyEvent.VK_DOWN);
 window.comboBox().pressAndReleaseKeys(KeyEvent.VK_ENTER);
 

This is not an answer to the question, but a workaround that allows the desired behavior. This issue can be mitigated by invoking robot() for the comboBox().

Instead of

window.comboBox().pressAndReleaseKeys(KeyEvent.VK_S);

try doing

window.comboBox().robot().pressAndReleaseKeys(KeyEvent.VK_S);