Enabling Test-First Development for
Eclipse UI
Matthias Kempka
Innoopract Informationssysteme GmbH

Outline
 Problem description
 Components for testing UI programmatically
 Test Case with JFace/Workbench Robot Sammy

Creating code test-driven
 TDD creates little pieces of code
 Readable
 Simple
 Flexible
 Regression tests already there
 Great, uh?
Unit Tests
Piece of Code

Where should I put it?
 A framework has many hooks
 Did I hook up my PoC in the right spot?
 Did I hook it up at all?
Eclipse Framework
Piece of Code

„Testing“ by hand
 Easiest approach: Try it.
 Regression tests?
*click*
Developer
use
Eclipse Framework
Piece of Code

PDE Tests
 Let's write regression tests
 PDE tests can start our test code with a workbench
 Some Eclipse functionality is hard to reach programmatically
PDE Unit Tests
Eclipse Framework
Piece of Code

Functional Tests with SWT Robots
 SWT Robots can simulate User interaction
 Is it easier to find a ViewAction button on the screen than in the Workbench
API?
PDE Unit Tests
use SWT *click*
Robot
use
Eclipse Framework
Piece of Code

Are SWT Robots the solution?
 Can find SWT widgets in the widget hierarchy
 Provides convenience methods to use the widgets
 Can read feedback from the UI
Display
Shell
Composite
Label Text

What's not in the Widget Hierarchy?
 Basically all objects an Eclipse programmer touches are not in the widget
hierarchy
 Association with IDs from plugin.xml is lost
Display IViewPart IActionDelegate
Shell IMarker
IEditorPart
Composite TreeViewer
IHandler
Label Text TableViewer
...

Functional Tests with Robots
 A JFace/Workbench Robot eases access to the interesting parts of the UI.
 Provides access to JFace controllers
SWT Robot *click*
PDE Unit Tests
JFace/Workbench
Robot
use
Eclipse Framework
Piece of Code

Sammy: The Mission
Make common things easy, make difficult things possible
 I need to set up test data for the TableViewer behind this SWT Table on the
screen? How can I reach it?
 I'm writing a view. How can I test that all the listeners are attached correctly?
 I'm writing a contribution to a view (i.e. a ViewAction) – How can I test that
my entries in plugin.xml works?
 Does my LabelProvider return the right image?

Writing a test with JFace/Workbench Robot
Sammy
Write a test case:
 Set up: Prepare a view for the actual test
– open the view
 Tear down:
– Clean up allocated resources: Close the view
 Actual test
– Find the TableViewer in that view and set a test-specific input
– Check that a view action is not enabled
– Select an item in the table
– Check that the view action is enabled

Set up: Open a view
 Views could be opened using IWorkbenchPage.showView( id )
– Too cumbersome for such a common use case
– No immediate feedback on errors
 Sammy.openView( id ) eases setting up test cases
– easy accessible API
– Show errors in red test case instead of UI
– Remembers the view for cleaning up
public void setup() throws Exception {
sammy = new Sammy();
sammy.openView( ViewUnderTest.ID );
}

Tear down
 Instances of Sammy (and SammyIDE) remember the resources they
allocated and can release (close or delete) them
– IViewPart
– IEditorPart
– IResource
public void teardown() throws Exception {
sammy.cleanup();
}

Test: Finding the view
 Every supported JFace/Workbench Element has an Operator:
– IViewPart – ViewOperator
– IEditorPart – EditorOperator
– TableViewer – TableViewerOperator
– …
 The Operator gives access to the described JFace/Workbench element
– Convenience methods for common use cases
 Operator constructor
– takes parameters that describe the JFace/Workbench element
– returns without Exception only if the described element was found
– waits a time for the element to appear
public void testViewAction() throws Exception {
ViewOperator vo = new ViewOperator( “View Title” );
}

Test: Finding the TableViewer
 Operators for workbench parts know their parent composite
– Given in IWorkbenchPart.createPartControl( Composite )
 Operators for JFace elements
– take a parent of the SWT element or the SWT element itself
– can associate the SWT element with the JFace abstraction
public void testViewAction() throws Exception {
ViewOperator vo = new ViewOperator( “View Title” );
TableViewerOperator tvo = new TableViewerOperator(
vo.getParentComposite() );
}

Test: Setting the Input
 Setting up Test Data often includes setting a special input on a viewer
 Having the TableViewer already available eases this remarkably
 *Operator.getSource()returns the actual JFace/Workbench element
public void testViewAction() throws Exception {
ViewOperator vo = new ViewOperator( “View Title” );
TableViewerOperator tvo = new TableViewerOperator(
vo.getParentComposite() );
tvo.getSource().setInput( new String[] { “a” } );
}

Test: Checking ViewerOperator enablement
 A ViewActionDelegate only is instanciated once the user selects the
ViewAction
 The ViewActionOperator knows the Proxy by the workbench as well as
the delegate
public void testViewAction() throws Exception {
ViewOperator vo = new ViewOperator( “View Title” );
TableViewerOperator tvo = new TableViewerOperator(
vo.getParentComposite() );
tvo.getSource().setInput( new String[] { “a” } );
ViewActionOperator vao = new ViewActionOperator( vo,
MyViewAction.ID );
assertFalse( vao.isEnabled() );
}

Test: Checking ViewerOperator enablement
 Now all the elements are in place to make this test useful
– The View shows up (layout is not tested)
– XML Code in plugin.xml is tested
– Makes sure that the TableViewer is a SelectionProvider
public void testViewAction() throws Exception {
ViewOperator vo = new ViewOperator( “View Title” );
TableViewerOperator tvo = new TableViewerOperator(
vo.getParentComposite() );
tvo.getSource().setInput( new String[] { “a” } );
ViewActionOperator vao = new ViewActionOperator( vo,
MyViewAction.ID );
assertFalse( vao.isEnabled() );
tvo.getSource().setSelection( new StructuredSelection(“a”));
assertTrue( vao.isEnabled() );
}

Sammy Internals
 For many things, Sammy relies on mapping from widgets to
JFace/Workbench elements
– And vice versa
 Some widgets are nowhere accessible in the workbench
– Where necessary aspects are used to trap widget instances
 For some things, Sammy has to access internals
– i.e. the View that shows an error holds it in a private field
– This leads to compatibility layers, but at least it's in one place
Widget Viewer

Sammy Future
 More than proof of concept, less than beta
 A good state to start collecting requirements
 http://www.innoopract.com/en/developers/mkempka/sammy

The End
http://www.innoopract.com/en/developers/mkempka/sammy