Bug 291934 Sash tests failing over part renderer call
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/workbench/RenderingTestCase.java
import org.eclipse.e4.ui.model.internal.application.MStackImpl;
import org.eclipse.e4.ui.model.internal.application.MWindowImpl;
import org.eclipse.e4.ui.tests.Activator;
import org.eclipse.e4.ui.workbench.swt.internal.PartRenderingEngine;
import org.eclipse.e4.workbench.ui.internal.ReflectionContributionFactory;
import org.eclipse.e4.workbench.ui.internal.Workbench;
import org.eclipse.emf.common.util.EList;
import org.eclipse.jface.databinding.swt.SWTObservables;
import org.eclipse.swt.custom.CTabFolder;
import org.eclipse.swt.custom.SashForm;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Sash;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Widget;
/**
 * This is the base class for tests involving the interactions between the UI
 * Model and the SWT Renderer. It is optimized to reduce the overhead
 * <p>
 * It provides various utility methods but also enforces automatic tests to
 * ensure that all models rendered through it conform to the expected structural
 * result:
 * <ol>
 * <li>All visible UI Model elements result in a widget</li>
 * <li>The UI Model element and its SWT Widget are correctly 'bound'</li>
 * <li>The correct SWT widget is created for a given UI Model element</li>
 * <ul>
 * <li>MWindow -> Shell</li>
 * <li>MSashForm -> SashForm</li>