NullPointerException in WorkbenchPage.busyShowView

Question

I have a simple view registered normally in my Eclipse plug-in (4.5.2), and it works when I start an Eclipse instance with the plug-in. It still works in the corresponding test case, which has the following method:

@Before
public void setUp() throws Exception {
    IWorkbenchPage activePage = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage();
    for (IViewReference viewReference : activePage.getViewReferences()) {
        activePage.hideView(viewReference);
    }
    activePage.showView("org.acme.MyView");
}

Yet when I run the same test with Tycho (0.22, 0.24 or 0.25), I get the following exception:

java.lang.NullPointerException: null
    at org.eclipse.ui.internal.WorkbenchPage.busyShowView(WorkbenchPage.java:1271)
    at org.eclipse.ui.internal.WorkbenchPage$12.run(WorkbenchPage.java:4238)
    at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
    at org.eclipse.ui.internal.WorkbenchPage.showView(WorkbenchPage.java:4234)
    at org.eclipse.ui.internal.WorkbenchPage.showView(WorkbenchPage.java:4214)
    at org.acme.MyViewTest.setUp(MyViewTest.java:39)

The Tycho code is simple:

<plugin>
    <groupId>org.eclipse.tycho</groupId>
    <artifactId>tycho-surefire-plugin</artifactId>
    <configuration>
        <providerHint>junit4</providerHint>
        <useUIHarness>true</useUIHarness>
    </configuration>
</plugin>

I found this bug and a couple more, but I found nothing explaining why it would only fail in Tycho. And I couldn't find anything on how to fix this.

So what did I do wrong? How do I fix it?

Answer 1

My guess would be that something is missing in your test runtime that’s required by the full-blown Eclipse workbench and which PDE adds, but Tycho doesn’t. (By default, Tycho only adds the (transitive) dependencies of your eclipse-test-plugin to the test runtime.)

Try adding the following to your tycho-surefire-plugin execution:

<configuration>
  <!-- ... ->
  <dependencies>
    <dependency>
      <artifactId>org.eclipse.e4.rcp</artifactId>
      <type>eclipse-feature</type>
    </dependency>
  </dependencies>
</configuration>

This should pull a lot of plugins into your test runtime that may not be present otherwise (like org.eclipse.e4.core.di, which tests normally don’t depend on directly or indirectly).

Of course, the above only works if the org.eclipse.e4.rcp feature is part of your target platform.