Faced missing displayed views in Espresso tests

They seem to only depends on MaterialDialog timings...
I'd like to avoid writing code in packaged classes just to manage timing as Idling Resources or BusyBee require.

omniNotes/src/androidTest/java/it/feio/android/omninotes/ui/BaseEspressoTest.java

@@ -18,32 +18,37 @@
 package it.feio.android.omninotes.ui;
 
 
-import static androidx.test.espresso.Espresso.onData;
 import static androidx.test.espresso.Espresso.onView;
 import static androidx.test.espresso.action.ViewActions.click;
 import static androidx.test.espresso.action.ViewActions.closeSoftKeyboard;
 import static androidx.test.espresso.action.ViewActions.replaceText;
 import static androidx.test.espresso.action.ViewActions.scrollTo;
 import static androidx.test.espresso.matcher.ViewMatchers.isDisplayed;
+import static androidx.test.espresso.matcher.ViewMatchers.isRoot;
 import static androidx.test.espresso.matcher.ViewMatchers.withClassName;
 import static androidx.test.espresso.matcher.ViewMatchers.withContentDescription;
 import static androidx.test.espresso.matcher.ViewMatchers.withId;
 import static androidx.test.espresso.matcher.ViewMatchers.withParent;
 import static org.hamcrest.Matchers.allOf;
-import static org.hamcrest.Matchers.anything;
 import static org.hamcrest.Matchers.is;
 
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewParent;
 import androidx.core.view.GravityCompat;
+import androidx.test.espresso.PerformException;
+import androidx.test.espresso.UiController;
+import androidx.test.espresso.ViewAction;
 import androidx.test.espresso.ViewInteraction;
 import androidx.test.espresso.contrib.RecyclerViewActions;
 import androidx.test.espresso.matcher.ViewMatchers;
+import androidx.test.espresso.util.HumanReadables;
+import androidx.test.espresso.util.TreeIterables;
 import androidx.test.rule.ActivityTestRule;
 import it.feio.android.omninotes.BaseAndroidTestCase;
 import it.feio.android.omninotes.MainActivity;
 import it.feio.android.omninotes.R;
+import java.util.concurrent.TimeoutException;
 import org.hamcrest.Description;
 import org.hamcrest.Matcher;
 import org.hamcrest.Matchers;
@@ -129,4 +134,48 @@ void navigateUpSettings () {
             1), isDisplayed())).perform(click());
   }
 
+  /**
+   * Perform action of waiting for a specific view id.
+   * @param viewId The id of the view to wait for.
+   * @param millis The timeout of until when to wait for.
+   */
+  public static ViewAction waitId(final int viewId, final long millis) {
+    return new ViewAction() {
+      @Override
+      public Matcher<View> getConstraints() {
+        return isRoot();
+      }
+
+      @Override
+      public String getDescription() {
+        return "wait for a specific view with id <" + viewId + "> during " + millis + " millis.";
+      }
+
+      @Override
+      public void perform(final UiController uiController, final View view) {
+        uiController.loopMainThreadUntilIdle();
+        final long startTime = System.currentTimeMillis();
+        final long endTime = startTime + millis;
+        final Matcher<View> viewMatcher = withId(viewId);
+
+        do {
+          for (View child : TreeIterables.breadthFirstViewTraversal(view)) {
+            if (viewMatcher.matches(child)) {
+              return;
+            }
+          }
+
+          uiController.loopMainThreadForAtLeast(50);
+        }
+        while (System.currentTimeMillis() < endTime);
+
+        throw new PerformException.Builder()
+            .withActionDescription(this.getDescription())
+            .withViewDescription(HumanReadables.describe(view))
+            .withCause(new TimeoutException())
+            .build();
+      }
+    };
+  }
+
 }

omniNotes/src/androidTest/java/it/feio/android/omninotes/ui/CategoryLifecycleTest.java

@@ -27,6 +27,7 @@
 import static androidx.test.espresso.assertion.ViewAssertions.doesNotExist;
 import static androidx.test.espresso.assertion.ViewAssertions.matches;
 import static androidx.test.espresso.matcher.ViewMatchers.isDisplayed;
+import static androidx.test.espresso.matcher.ViewMatchers.isRoot;
 import static androidx.test.espresso.matcher.ViewMatchers.withContentDescription;
 import static androidx.test.espresso.matcher.ViewMatchers.withId;
 import static androidx.test.espresso.matcher.ViewMatchers.withParent;
@@ -44,7 +45,6 @@
 import androidx.appcompat.widget.AppCompatImageView;
 import androidx.test.espresso.matcher.ViewMatchers;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
-import androidx.test.filters.FlakyTest;
 import androidx.test.filters.LargeTest;
 import it.feio.android.omninotes.R;
 import java.util.Calendar;
@@ -77,9 +77,11 @@ public void addNewCategory () throws InterruptedException {
     onView(allOf(withId(R.id.menu_category), withContentDescription(R.string.category), isDisplayed())).perform(
         click());
 
+    // Materialdialog "Add Category"
+    onView(isRoot()).perform(waitId(R.id.md_buttonDefaultPositive, 5000));
+
     onView((withText(R.string.add_category))).perform(click());
 
-    sleep(1000);
     onView(withId(R.id.category_title)).perform(replaceText(categoryName), closeSoftKeyboard());
 
     onView(allOf(withId(R.id.save), withText("Ok"), isDisplayed())).perform(click());
@@ -97,11 +99,9 @@ public void addNewCategory () throws InterruptedException {
     onView(allOf(withContentDescription(R.string.drawer_open),
         withParent(withId(R.id.toolbar)),
         isDisplayed())).perform(click());
-
   }
 
   @Test
-  @FlakyTest(detail = "Fixme with Idling Resources or BusyBee") // FIXME
   public void checkCategoryCreation () throws InterruptedException {
 
     addNewCategory();
@@ -157,11 +157,9 @@ public void categoryColorChange () throws InterruptedException {
 
     onView(allOf(withId(R.id.color_chooser), isDisplayed())).check(
         matches(withBackgroundColor(Color.parseColor("#FF263238"))));
-
   }
 
   @Test
-  @FlakyTest(detail = "Fixme with Idling Resources or BusyBee") // FIXME
   public void categoryDeletion () throws InterruptedException {
 
     addNewCategory();