protected static void openPart(final String id) {
    Display.getDefault().syncExec(new Runnable() {

        public void run() {
            EPartService partService = E4Workbench.getServiceContext().getActiveLeaf().get(EPartService.class);
            MPart part = partService.findPart(id);
            partService.activate(part);
        }
    });
}

@Test
public void test1() {
    openPart("testmaker.part.gauche");
    bot.tree().getTreeItem("hju / PQT").expand();
}

@Test
public void test2() {
    openPart("testmaker.part.stepRightSide");
    bot.button("Add Comment").click();
}