gwtmockito and GXT

[fpezzati]

Hello,

I'm trying to build unit tests about widget who uses GWT 2.7.0 and GXT 3.1.4 components. Unfortunately as soon as test encounter a GXT component it raises a NullPointerException. Here is my dummy widget:

public class SomePanel {

private HorizontalPanel pnl;
private Button btn;
private Label lbl;
private TextButton displaySome;

public SomePanel() {
   pnl = new HorizontalPanel();
   btn = new Button("Hey");
   lbl = new Label("Unclicked");
   btn.addClickHandler(new ClickHandler() {
       @Override
       public void onClick(ClickEvent event) {
           if ("Unclicked".equals(lbl.getText())) {
               lbl.setText("Clicked");
           } else {
               lbl.setText("Unclicked");
           }
       }
   });
   displaySome = new TextButton("Display some.");
 }

 public HorizontalPanel getPnl() {
   return pnl;
 }

 public Button getBtn() {
   return btn;
 }

 public Label getLbl() {
   return lbl;
 }

 public TextButton getDisplaySome() {
   return displaySome;
 }
}

And this is the test who goes wrong:

@RunWith(GwtMockitoTestRunner.class)
public class SomePanelTest {

  private SomePanel pnl;

  @Test
  public void checkLabels() {
    pnl = new SomePanel();
    Assert.assertEquals("Unclicked", pnl.getLbl().getText());
    pnl.getBtn().click();
    Assert.assertEquals("Clicked", pnl.getLbl().getText());
    pnl.getBtn().click();
    Assert.assertEquals("Unclicked", pnl.getLbl().getText());
    Assert.assertEquals("Display", pnl.getDisplaySome().getText());
  }
}

This is the exception:

java.lang.NullPointerException
at com.sencha.gxt.core.client.resources.CommonStyles.get(CommonStyles.java:96)
at com.sencha.gxt.widget.core.client.cell.CellComponent.createDefaultWrapperElement(CellComponent.java:55)
at com.sencha.gxt.widget.core.client.cell.CellComponent.<init>(CellComponent.java:141)
at com.sencha.gxt.widget.core.client.button.CellButtonBase.<init>(CellButtonBase.java:44)
at com.sencha.gxt.widget.core.client.button.TextButton.<init>(TextButton.java:35)
at com.sencha.gxt.widget.core.client.button.TextButton.<init>(TextButton.java:25)
at edu.me.gwt.client.SomePanel.<init>(SomePanel.java:32)
...

I would like to know if gwtmockito is the right tool to use together GXT (I am bound to GXT 3.1.4) and if it is, what am I missing then. TIA.

[ekuefler]

Most likely this means that there's a class inside GXT somewhere that's relying on a native method. Could you try annotating your test with either @WithClassesToStub(TextButton.class) or @WithClassesToSub(CommonStyle.class) and see if that helps? More details at https://static.javadoc.io/com.google.gwt.gwtmockito/gwtmockito/1.1.8/com/google/gwtmockito/WithClassesToStub.html.