Testing SWT application with SWTBot

SWTBot is open-source Java based UI/functional testing tool for testing SWT and Eclipse based applications.

SWTBot provides APIs that are simple to read and write. The APIs also hide the complexities involved with SWT and Eclipse. This makes it suitable for UI/functional testing by everyone, not just developers. SWTBot also provides its own set of assertions that are useful for SWT. You can also use your own assertion framework with SWTBot.

There are many articles present for SWTBot for Eclipse Plug-in and RCP applications. Refer the following links for more details:

1. Articles and Tutorials
2. Users Guide
3. SWTBot Article
4. Cheat sheet

As the title suggest, the intention of this article to demonstrate the testing of a stand-alone SWT UI. There was a question asked  on the Stackoverflow with the same problem. You can checkout my answer there also. For completeness purpose I am posting it here too.

Well it is very much possible to test simple SWT application with SWTBot. Follow the step as mentioned below.

1. Download SWTBot for SWT Testing
   
2. Put it in the <eclipsehome>/dropins folder (although not required for non-plug-in projects)
   
3. Restart your eclipse (not required if you adding the SWTBot jars in a simple Java project)

Now at this point you are ready to play with SWTBot.

For the demo purpose I have written a small Login dialog for you and it will look like this:

>>Code

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;

public class SampleSWTUI 
{
   public Shell showGUI(final Display display)
   {
       Shell shell = new Shell(display);
       shell.setLayout(new GridLayout(3,true));
       shell.setText("Sample SWT UI");

       new Label(shell, SWT.NONE).setText("User Name: ");
       final Text nameText = new Text(shell, SWT.BORDER);
       nameText.setText ("");
       GridData data = new GridData(SWT.FILL, SWT.FILL, true, false);
       data.horizontalSpan = 2;
       nameText.setLayoutData(data);

       new Label(shell, SWT.NONE).setText("Password: ");
       final Text passwordText = new Text(shell, SWT.BORDER|SWT.PASSWORD);
       passwordText.setText ("");
       data = new GridData(SWT.FILL, SWT.FILL, true, false);
       data.horizontalSpan = 2;
       passwordText.setLayoutData(data);

       Button loginButton = new Button (shell, SWT.PUSH);
       loginButton.setText ("Login");
       data = new GridData(SWT.FILL, SWT.FILL, true, false);
       data.horizontalSpan = 3;
       loginButton.setLayoutData(data);
       loginButton.addSelectionListener(new SelectionAdapter(){
           public void widgetSelected(SelectionEvent e) {
                String user = nameText.getText();
                String password = passwordText.getText();

                System.out.println("\n\n\n");
                if(user.equals("Favonius") && password.equals("abcd123")){
                    System.out.println("Success !!!");
                }else {
                    System.err.println("What the .. !! Anyway it is just a demo !!");
                }                   
           }
       });

       shell.pack();
       shell.open();
       return shell;
   }

   public static void main(String [] args) 
   {
       Display display = new Display();
       Shell shell = new SampleSWTUI().showGUI(display);
       while (!shell.isDisposed()) {
           if (!display.readAndDispatch()) display.sleep();
       }

       display.dispose();
   }
}

Now create a JUnit test case (google for it if you are new to it) . Also add all the jar files present in SWTBot (the one you have downloaded) in your classpath.

Now first create a display (because application needs one). Also get the handle of container in which your widgets/controls are present. In my case it is the Shell. Although the below code is self descriptive, still, I will suggest you to refer its Javadoc.

>>SWTBot Code

import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swtbot.swt.finder.SWTBot;
import org.eclipse.swtbot.swt.finder.utils.SWTBotPreferences;
import org.eclipse.swtbot.swt.finder.widgets.SWTBotButton;
import org.eclipse.swtbot.swt.finder.widgets.SWTBotText;
import org.junit.Test;

import junit.framework.Assert;

public class SWTBotDemo 
{
    @Test
    public void test() 
    {
        SWTBotPreferences.PLAYBACK_DELAY = 100; // slow down tests...Otherwise we won't see anything
  
        Display display = new Display();
        Shell shell = new SampleSWTUI().showGUI(display);
        SWTBot bot = new SWTBot(shell);
  
        SWTBotButton loginButton = bot.button("Login");
        SWTBotText userText = bot.textWithLabel("User Name: ");
        SWTBotText passwordText = bot.textWithLabel("Password: ");
  
        userText.setFocus();
        userText.setText("Superman");
  
        Assert.assertEquals(userText.getText(),"Superman");
  
        passwordText.setFocus();
        passwordText.setText("test123");
  
        Assert.assertEquals(passwordText.getText(),"test123");
  
        loginButton.setFocus();
        loginButton.click(); 
  
  
        userText.setFocus();
        userText.setText("Favonius");
  
        Assert.assertEquals(userText.getText(), "Favonius");
  
        passwordText.setFocus();
        passwordText.setText("abcd123");
  
        Assert.assertEquals(passwordText.getText(), "abcd123");
  
        loginButton.setFocus();
        loginButton.click();
        
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) display.sleep();
        }

        display.dispose();
    }
}

Now all the SWTBot methods and variables are well defined in the source and the source is bundled within the SWTBot jars. So you can always go ahead and hack its source code.

>>Further Reading

1. SWTBot FAQ

Detecting change in SWT Table's scrollbar visibility

Recently on stackoverflow there was a question asked related to this. The requirement was simple ‘resize all the columns as soon as scrollbar appears or disappears’. Now, if you look deep into the SWT table API then you will notice that there is no direct solution for this because:

1. There is no way to get the scrollbar handle
2. Scrollbar does not support any event related to visibility

One can solve this problem by implementing a simple hack. I am using the concept presented in this SWT snippet compute the visible rows in a table. Along with that I am also using SWT Paint Event.

The basic concept is as follows:

1. Calculate the number of visible rows (items).
2. Compare it with total number of rows (items).
3. Do all this in some event which occurs with the addition of rows (items). I have chosen the SWT Paint Event

>> Code

import org.eclipse.swt.*;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

public class TableScrollVisibilityTest 
{
    private static int count;

    public static void main(String [] args) 
    {
        Display display = new Display();
        Shell shell = new Shell(display);
        shell.setBounds(10,10,300,300);
        shell.setLayout(new GridLayout(2,true));

        final Table table = new Table(shell, SWT.NONE);
        GridData data = new GridData(GridData.FILL_BOTH);
        data.horizontalSpan = 2;
        table.setLayoutData(data);

        count = 0;

        final Button addItem = new Button (shell, SWT.PUSH);
        addItem.setText ("Add Row");
        data = new GridData(SWT.FILL, SWT.FILL, true, false);
        data.horizontalSpan = 2;
        addItem.setLayoutData(data);

        final Text text = new Text(shell, SWT.BORDER);
        text.setText ("Vertical Scroll Visible - ");
        data = new GridData(SWT.FILL, SWT.FILL, true, false);
        data.horizontalSpan = 2;
        text.setLayoutData(data);


        addItem.addListener (SWT.Selection, new Listener () 
        {
            public void handleEvent (Event e) 
            {
                new TableItem(table, SWT.NONE).setText("item " + count);
                count++;
            }
        });


        table.addPaintListener(new PaintListener() {
            public void paintControl(PaintEvent e) {
                Rectangle rect = table.getClientArea ();
                int itemHeight = table.getItemHeight ();
                int headerHeight = table.getHeaderHeight ();
                int visibleCount = (rect.height - headerHeight + itemHeight - 1) / itemHeight;
                text.setText ("Vertical Scroll Visible - [" + (table.getItemCount()>= visibleCount)+"]");

                      // YOUR CODE HERE
            }
        });


        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) display.sleep();
        }

        display.dispose();
    }

}

>> Output

For itemcount < numberofvisible rows

For itemcount >= numberofvisible rows

Note - If you are going to use the paint event then try keep the calculations minimum as it is called frequently.

Link to the actual problem: Stackoverflow - How to detect SWT Table's scroll bar visibility changes

SWT Browser and Javascript

Sometime we feel the need of modifying SWT browser content dynamically. Using getText and modifying it is not the advisable way of changing HTML content. I will suggest you to use execute() method of org.eclipse.swt.browser.Browser. It allows you to fire javascripts on the DOM object of the page.

>> Example

Here in this code I am allowing the page to fully load and then looking for all the links item and then creating a red border around them.

import org.eclipse.swt.SWT;
import org.eclipse.swt.SWTError;
import org.eclipse.swt.browser.Browser;
import org.eclipse.swt.browser.LocationEvent;
import org.eclipse.swt.browser.LocationListener;
import org.eclipse.swt.browser.ProgressEvent;
import org.eclipse.swt.browser.ProgressListener;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;
import org.eclipse.swt.widgets.ToolBar;
import org.eclipse.swt.widgets.ToolItem;

public class BrowserTest 
{
 private static Browser browser;

 public static void main(String [] args) 
 {
  Display display = new Display();
  final Shell shell = new Shell(display);
  GridLayout gridLayout = new GridLayout();
  gridLayout.numColumns = 3;
  shell.setLayout(gridLayout);

  createBrowser(shell);

  browser.addProgressListener(new ProgressListener() 
  {
   public void changed(ProgressEvent event) {
   }
   public void completed(ProgressEvent event) {
    changeSomething();
   }
  });

  shell.open();
  browser.setUrl("http://google.com");

  while (!shell.isDisposed()) {
   if (!display.readAndDispatch())
    display.sleep();
  }
  display.dispose();
 }

 protected static void changeSomething() 
 {
  String s = "var allLinks = document.getElementsByTagName('a'); " +
    "for (var i=0, il=allLinks.length; i<il; i++) { " +
     "elm = allLinks[i]; elm.style.border = 'thin solid red';" +
    "}";

  System.out.println(browser.execute(s));
 }

 private static void createBrowser(Shell shell) 
 {
  ToolBar toolbar = new ToolBar(shell, SWT.NONE);
  ToolItem itemGo = new ToolItem(toolbar, SWT.PUSH);
  itemGo.setText("Go");

  GridData data = new GridData();
  data.horizontalSpan = 3;
  toolbar.setLayoutData(data);

  Label labelAddress = new Label(shell, SWT.NONE);
  labelAddress.setText("Address");

  final Text location = new Text(shell, SWT.BORDER);
  data = new GridData();
  data.horizontalAlignment = GridData.FILL;
  data.horizontalSpan = 2;
  data.grabExcessHorizontalSpace = true;
  location.setLayoutData(data);

  try {
   browser = new Browser(shell, SWT.NONE);
  } catch (SWTError e) {
   System.out.println("Could not instantiate Browser: " + e.getMessage());
   //display.dispose();
   return;
  }
  data = new GridData(SWT.FILL, SWT.FILL, true, true);
  data.horizontalSpan = 3;
  browser.setLayoutData(data);

  /* event handling */
  Listener listener = new Listener() 
  {
   public void handleEvent(Event event) 
   {
    ToolItem item = (ToolItem)event.widget;
    String string = item.getText();
    if (string.equals("Go")) browser.setUrl(location.getText());
   }
  };

  browser.addLocationListener(new LocationListener() {
   public void changed(LocationEvent event) {
    if (event.top) location.setText(event.location);
   }
   public void changing(LocationEvent event) {
   }
  });


  itemGo.addListener(SWT.Selection, listener);
  location.addListener(SWT.DefaultSelection, new Listener() {
   public void handleEvent(Event e) {
    browser.setUrl(location.getText());
   }
  });  
 }
}

>>Output

>> Further Reading

1. Eclipse Article
   
2. SWT Snippets