Execute browser tests for Edge #671

Browser tests were only executed for the default configuration of a
system's browser using the SWT.NONE flag. Other configurations, such as
using the Edge browser in Windows, were not tested. A parameterization
has been added to allow other configurations to be tested.

This change adds Edge to the test configurations executed for the
browser. This allows to detect regressions when performing future
changes to the Edge browser.

Fixes
#671

tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_browser_Browser.java

@@ -81,6 +81,7 @@
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.swt.widgets.Text;
 import org.junit.Before;
+import org.junit.BeforeClass;
 import org.junit.FixMethodOrder;
 import org.junit.Rule;
 import org.junit.Test;
@@ -145,13 +146,10 @@ private void testLogAppend(String msg) {
 @Parameters(name = "browser flags: {0}")
 public static Collection<Object[]> browserFlagsToTest() {
 	List<Object[]> browserFlags = new ArrayList<>();
+	browserFlags.add(new Object[] {SWT.NONE});
 	if (SwtTestUtil.isWindows) {
-		// NOTE: This is currently disabled due to test issues in the CI
-		// Execute Edge tests first, because IE starts some OS timer that conflicts with Edge event handling
-		// browserFlags.add(0, new Object[] {SWT.EDGE});
+		// Execute IE tests after Edge, because IE starts some OS timer that conflicts with Edge event handling
 		browserFlags.add(new Object[] {SWT.IE});
-	} else {
-		browserFlags.add(new Object[] {SWT.NONE});
 	}
 	return browserFlags;
 }
@@ -160,6 +158,16 @@ public Test_org_eclipse_swt_browser_Browser(int swtBrowserSettings) {
 	this.swtBrowserSettings = swtBrowserSettings;
 }
 
+@BeforeClass
+public static void setupEdgeEnvironment() {
+	// initialize Edge environment before any test runs to isolate environment setup
+	if (SwtTestUtil.isWindows) {
+		Shell shell = new Shell();
+		new Browser(shell, SWT.EDGE);
+		shell.dispose();
+	}
+}
+
 @Override
 @Before
 public void setUp() {
@@ -234,6 +242,16 @@ protected void afterDispose(Display display) {
 			printThreadsInfo();
 		}
 	}
+	if (isEdge) {
+		// wait for and process pending events to properly cleanup Edge browser resources
+		do {
+			processUiEvents();
+			try {
+				Thread.sleep(100);
+			} catch (InterruptedException e) {
+			}
+		} while (Display.getCurrent().readAndDispatch());
+	}
 	if (SwtTestUtil.isGTK) {
 		int descriptorDiff = reportOpenedDescriptors();
 		if(descriptorDiff > 0) {