Simplify Robolectric UI test waits

Author: shai-almog

scripts/templates/HelloCodenameOneUiTest.java.tmpl

@@ -5,6 +5,7 @@ import static org.junit.Assert.assertTrue;
 
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
+import android.os.SystemClock;
 import android.util.DisplayMetrics;
 import android.view.View;
 
@@ -14,24 +15,21 @@ import com.codename1.ui.Form;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicReference;
-
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.robolectric.Robolectric;
 import org.robolectric.RobolectricTestRunner;
 import org.robolectric.android.controller.ActivityController;
 import org.robolectric.annotation.Config;
+import org.robolectric.shadows.ShadowLooper;
 
 @RunWith(RobolectricTestRunner.class)
 @Config(sdk = 30)
 public class @MAIN_NAME@UiTest {
 
     @Test
     public void mainFormScreenshotContainsRenderedContent() throws Exception {
-        ActivityController<@MAIN_NAME@Stub> controller = Robolectric.buildActivity(@[email protected]).setup();
+        ActivityController<@MAIN_NAME@Stub> controller = Robolectric.buildActivity(@[email protected]).setup().visible();
         try {
             Form displayed = waitForDisplayedForm(5000L);
             assertNotNull("Codename One form should be displayed", displayed);
@@ -52,13 +50,13 @@ public class @MAIN_NAME@UiTest {
     }
 
     private static Form waitForDisplayedForm(long timeoutMillis) throws InterruptedException {
-        long deadline = System.currentTimeMillis() + timeoutMillis;
-        final Form[] current = new Form[1];
-        while (System.currentTimeMillis() < deadline) {
+        long deadline = SystemClock.uptimeMillis() + timeoutMillis;
+        while (SystemClock.uptimeMillis() < deadline) {
+            ShadowLooper.runUiThreadTasksIncludingDelayedTasks();
             if (Display.isInitialized()) {
-                Display.getInstance().callSeriallyAndWait(() -> current[0] = Display.getInstance().getCurrent());
-                if (current[0] != null) {
-                    return current[0];
+                Form current = Display.getInstance().getCurrent();
+                if (current != null) {
+                    return current;
                 }
             }
             Thread.sleep(50L);
@@ -69,10 +67,8 @@ public class @MAIN_NAME@UiTest {
     private static Bitmap captureScreenshot(@MAIN_NAME@Stub activity) throws InterruptedException {
         View decorView = waitForDecorViewWithDimensions(activity, 5000L);
         Bitmap bitmap = Bitmap.createBitmap(decorView.getWidth(), decorView.getHeight(), Bitmap.Config.ARGB_8888);
-        runOnUiThreadAndWait(activity, () -> {
-            Canvas canvas = new Canvas(bitmap);
-            decorView.draw(canvas);
-        });
+        Canvas canvas = new Canvas(bitmap);
+        decorView.draw(canvas);
         return bitmap;
     }
 
@@ -120,57 +116,29 @@ public class @MAIN_NAME@UiTest {
     }
 
     private static View waitForDecorViewWithDimensions(@MAIN_NAME@Stub activity, long timeoutMillis) throws InterruptedException {
-        long deadline = System.currentTimeMillis() + timeoutMillis;
-        while (System.currentTimeMillis() < deadline) {
+        long deadline = SystemClock.uptimeMillis() + timeoutMillis;
+        while (SystemClock.uptimeMillis() < deadline) {
             View decorView = activity.getWindow().getDecorView();
             if (decorView != null) {
-                ensureViewHasLayout(activity, decorView);
+                ensureViewHasLayout(decorView);
                 if (decorView.getWidth() > 0 && decorView.getHeight() > 0) {
                     return decorView;
                 }
             }
+            ShadowLooper.runUiThreadTasksIncludingDelayedTasks();
             Thread.sleep(50L);
         }
         throw new AssertionError("Timed out waiting for decor view layout");
     }
 
-    private static void ensureViewHasLayout(@MAIN_NAME@Stub activity, View view) throws InterruptedException {
+    private static void ensureViewHasLayout(View view) {
         if (view.getWidth() > 0 && view.getHeight() > 0) {
             return;
         }
-        runOnUiThreadAndWait(activity, () -> {
-            DisplayMetrics metrics = activity.getResources().getDisplayMetrics();
-            int widthSpec = View.MeasureSpec.makeMeasureSpec(metrics.widthPixels, View.MeasureSpec.EXACTLY);
-            int heightSpec = View.MeasureSpec.makeMeasureSpec(metrics.heightPixels, View.MeasureSpec.EXACTLY);
-            view.measure(widthSpec, heightSpec);
-            view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
-        });
-    }
-
-    private static void runOnUiThreadAndWait(@MAIN_NAME@Stub activity, Runnable runnable) throws InterruptedException {
-        CountDownLatch latch = new CountDownLatch(1);
-        AtomicReference<Throwable> error = new AtomicReference<>();
-        activity.runOnUiThread(() -> {
-            try {
-                runnable.run();
-            } catch (Throwable t) {
-                error.set(t);
-            } finally {
-                latch.countDown();
-            }
-        });
-        if (!latch.await(5, TimeUnit.SECONDS)) {
-            throw new AssertionError("Timed out waiting for UI thread task");
-        }
-        if (error.get() != null) {
-            Throwable thrown = error.get();
-            if (thrown instanceof RuntimeException) {
-                throw (RuntimeException) thrown;
-            }
-            if (thrown instanceof Error) {
-                throw (Error) thrown;
-            }
-            throw new RuntimeException(thrown);
-        }
+        DisplayMetrics metrics = view.getResources().getDisplayMetrics();
+        int widthSpec = View.MeasureSpec.makeMeasureSpec(metrics.widthPixels, View.MeasureSpec.EXACTLY);
+        int heightSpec = View.MeasureSpec.makeMeasureSpec(metrics.heightPixels, View.MeasureSpec.EXACTLY);
+        view.measure(widthSpec, heightSpec);
+        view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
     }
 }