tests/contentcaptureservice/src/android/contentcaptureservice/cts/EventsAssertor.java - platform/cts - Git at Google

 /*
  * Copyright (C) 2021 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package android.contentcaptureservice.cts;

 import static android.contentcaptureservice.cts.Assertions.assertSessionId;

 import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.Truth.assertWithMessage;

 import android.text.TextUtils;
 import android.util.Log;
 import android.view.View;
 import android.view.autofill.AutofillId;
 import android.view.contentcapture.ContentCaptureEvent;
 import android.view.contentcapture.ContentCaptureSession;
 import android.view.contentcapture.ContentCaptureSessionId;
 import android.view.contentcapture.ViewNode;

 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;

 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;

 /**
  * Used to assert Content Capture events by the event order.
  *
  * When the type is the same, the assertor will assert the content of the event.
  * If the current event is different type, this event will be skipped, and then
  * try to assert the next event. Through all events, the assertor will report an
  * "not found" error.
  */
 public class EventsAssertor {
     private static final String TAG = "CtsContentCapture";
     private final List<ContentCaptureEvent> mEvents;
     private int mNextEvent = 0;

     public EventsAssertor(@NonNull List<ContentCaptureEvent> events) {
         mEvents = Collections.unmodifiableList(events);
     }

     @NonNull
     public EventsAssertor isAtLeast(int size) {
         assertThat(mEvents.size()).isAtLeast(size);
         return this;
     }

     /**
      * Asserts the contents of a {@link ContentCaptureEvent#TYPE_SESSION_RESUMED} event.
      */
     @NonNull
     public EventsAssertor assertSessionResumed() {
         assertNextEvent((event) -> assertSessionLevelEvent(event),
                 ContentCaptureEvent.TYPE_SESSION_RESUMED, "no SESSION_RESUMED event");
         return this;
     }

     /**
      * Asserts the contents of a {@link ContentCaptureEvent#TYPE_SESSION_PAUSED} event.
      */
     @NonNull
     public EventsAssertor assertSessionPaused() {
         assertNextEvent((event) -> assertSessionLevelEvent(event),
                 ContentCaptureEvent.TYPE_SESSION_PAUSED, "no SESSION_PAUSED event");
         return this;
     }

     /**
      * Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_TREE_APPEARING} event.
      */
     @NonNull
     public EventsAssertor assertViewTreeStarted() {
         assertNextEvent((event) -> assertSessionLevelEvent(event),
                 ContentCaptureEvent.TYPE_VIEW_TREE_APPEARING, "no VIEW_TREE_APPEARING event");
         return this;
     }

     /**
      * Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_TREE_APPEARED} event.
      */
     @NonNull
     public EventsAssertor assertViewTreeFinished() {
         assertNextEvent((event) -> assertSessionLevelEvent(event),
                 ContentCaptureEvent.TYPE_VIEW_TREE_APPEARED,
                 "no VIEW_TREE_APPEARED event");
         return this;
     }

     /**
      * Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_APPEARED}
      * event for a decor view.
      *
      * <P>The decor view is typically internal, so there isn't much we can assert,
      * other than its autofill id.
      */
     @NonNull
     public EventsAssertor assertDecorViewAppeared(@NonNull View expectedDecorView) {
         assertNextEvent((event) -> assertEventId(event, expectedDecorView),
                 ContentCaptureEvent.TYPE_VIEW_APPEARED,
                 "no VIEW_APPEARED event for decor view");
         return this;
     }

     /**
      * Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_APPEARED}
      * event, without checking for parent id.
      */
     @NonNull
     public EventsAssertor assertViewAppeared(@NonNull View expectedView) {
         assertNextEvent((event) -> assertViewEvent(event, expectedView),
                 ContentCaptureEvent.TYPE_VIEW_APPEARED,
                 String.format("no VIEW_APPEARED event for %s", expectedView));
         return this;
     }

     /**
      * Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_APPEARED} event.
      */
     @NonNull
     public EventsAssertor assertViewAppeared(@NonNull View expectedView,
             @NonNull AutofillId expectedParentId) {
         assertNextEvent((event) -> assertViewEvent(event, expectedView, expectedParentId),
                 ContentCaptureEvent.TYPE_VIEW_APPEARED,
                 String.format("no VIEW_APPEARED event for %s", expectedView));
         return this;
     }

     /**
      * Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_APPEARED} event.
      */
     @NonNull
     public EventsAssertor assertViewAppeared(@NonNull ContentCaptureSessionId expectedSessionId,
             @NonNull View expectedView, @NonNull AutofillId expectedParentId) {
         assertViewAppeared(expectedView, expectedParentId);
         assertSessionId(expectedSessionId, expectedView);
         return this;
     }


     /**
      * Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_APPEARED} event.
      */
     @NonNull
     public EventsAssertor assertViewAppeared(@NonNull ContentCaptureSessionId expectedSessionId,
             @NonNull View expectedView) {
         assertViewAppeared(expectedView);
         assertSessionId(expectedSessionId, expectedView);
         return this;
     }

     /**
      * Asserts the {@code text} of a {@link ContentCaptureEvent#TYPE_VIEW_APPEARED}
      * event.
      */
     @NonNull
     public EventsAssertor assertViewAppeared(@NonNull String text) {
         assertNextEvent((event) -> assertEventText(event, text),
                 ContentCaptureEvent.TYPE_VIEW_APPEARED,
                 String.format("no TYPE_VIEW_APPEARED event with text: %s", text));
         return this;
     }

     /**
      * Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_DISAPPEARED}
      * event for multiple views.
      */
     @NonNull
     public EventsAssertor assertViewDisappeared(@NonNull AutofillId autofillId) {
         assertNextEvent((event) -> assertDisappearedEvent(event, autofillId),
                 ContentCaptureEvent.TYPE_VIEW_DISAPPEARED,
                 String.format("no VIEW_DISAPPEARED event for %s", autofillId));
         return this;
     }

     /**
      * Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_DISAPPEARED}
      * event for multiple views.
      */
     @NonNull
     public EventsAssertor assertViewDisappeared(@NonNull AutofillId... autofillIds) {
         assertNextEvent((event) -> assertDisappearedEvent(event, autofillIds),
                 ContentCaptureEvent.TYPE_VIEW_DISAPPEARED,
                 String.format("no VIEW_DISAPPEARED event for %s", Arrays.toString(autofillIds)));
         return this;
     }

     /**
      * Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_TEXT_CHANGED} event.
      */
     @NonNull
     public EventsAssertor assertViewTextChanged(@NonNull AutofillId expectedId,
             @NonNull String expectedText) {
         assertNextEvent((event) -> assertTextChangedEvent(event, expectedId, expectedText),
                 ContentCaptureEvent.TYPE_VIEW_TEXT_CHANGED,
                 String.format("no VIEW_TEXT_CHANGED event for %s", expectedId));
         return this;
     }

     /**
      * Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_APPEARED}
      * event for a virtual node.
      */
     @NonNull
     public EventsAssertor assertVirtualViewAppeared(@NonNull ContentCaptureSession session,
             @NonNull AutofillId parentId, int childId, String expectedText) {
         final AutofillId expectedId = session.newAutofillId(parentId, childId);
         assertNextEvent((event) -> assertVirtualViewEvent(event, expectedId, expectedText),
                 ContentCaptureEvent.TYPE_VIEW_APPEARED,
                 String.format("no VIEW_APPEARED event for %s", expectedId.toString()));
         return this;
     }

     /**
      * Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_DISAPPEARED}
      * event for a virtual node.
      */
     @NonNull
     public EventsAssertor assertVirtualViewDisappeared(AutofillId parentId,
             ContentCaptureSession session, int childId) {
         return assertViewDisappeared(session.newAutofillId(parentId, childId));
     }

     /**
      * Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_DISAPPEARED}
      * event for many virtual nodes.
      */
     @NonNull
     public EventsAssertor assertVirtualViewsDisappeared(AutofillId parentId,
             ContentCaptureSession session, int... childId) {
         final AutofillId[] ids = new AutofillId[childId.length];
         for (int i = 0; i < childId.length; i++) {
             ids[i] = session.newAutofillId(parentId, childId[i]);
         }
         return assertViewDisappeared(ids);
     }

     @Nullable
     private String assertVirtualViewEvent(@NonNull ContentCaptureEvent event,
             @NonNull AutofillId expectedId, @Nullable String expectedText) {
         final ViewNode node = event.getViewNode();
         assertThat(node).isNotNull();
         if (!node.getAutofillId().equals(expectedId)) {
             return String.format("wrong autofill id (expected %s, actual is %s) at %s",
                     expectedId, node.getAutofillId(), event);
         }
         if (expectedText != null && node.getText() != null) {
             assertWithMessage("wrong text on %s", event)
                     .that(node.getText().toString()).isEqualTo(expectedText);
         } else {
             assertWithMessage("%s should not have text", node)
                     .that(node.getText()).isNull();
         }
         return null;
     }

     @Nullable
     private String assertDisappearedEvent(@NonNull ContentCaptureEvent event,
             @NonNull AutofillId expectedId) {
         assertCommonViewDisappearedProperties(event);
         assertWithMessage("wrong autofillId on event %s", event)
                 .that(event.getId()).isEqualTo(expectedId);
         assertWithMessage("event %s should not have autofillIds", event)
                 .that(event.getIds()).isNull();
         return null;
     }

     @Nullable
     private String assertDisappearedEvent(@NonNull ContentCaptureEvent event,
             @NonNull AutofillId[] expectedIds) {
         final List<AutofillId> ids = event.getIds();

         assertCommonViewDisappearedProperties(event);
         assertWithMessage("no autofillIds on event %s", event).that(ids)
                 .isNotNull();
         assertWithMessage("wrong autofillId on event %s", event)
                 .that(ids).containsExactly((Object[]) expectedIds).inOrder();
         assertWithMessage("event %s should not have autofillId", event)
                 .that(event.getId()).isNull();
         return null;
     }

     @Nullable
     private String assertTextChangedEvent(@NonNull ContentCaptureEvent event,
             @NonNull AutofillId expectedId, @NonNull String expectedText) {
         assertWithMessage("Wrong id on %s", event).that(event.getId())
                 .isEqualTo(expectedId);
         assertWithMessage("Wrong text on %s", event).that(event.getText().toString())
                 .isEqualTo(expectedText);
         return null;
     }

     private void assertCommonViewDisappearedProperties(@NonNull ContentCaptureEvent event) {
         assertWithMessage("event %s should not have a ViewNode", event)
                 .that(event.getViewNode()).isNull();
         assertWithMessage("event %s should not have text", event)
                 .that(event.getText()).isNull();
     }

     @Nullable
     private String assertViewEvent(@NonNull ContentCaptureEvent event, @NonNull View expectedView) {
         return assertViewEvent(event, expectedView, /* expectedParentId */ null);
     }

     @Nullable
     private String assertViewEvent(@NonNull ContentCaptureEvent event, @NonNull View expectedView,
             @Nullable AutofillId expectedParentId) {
         assertEvent(event, expectedView, expectedParentId, /* expectedText */  null);
         return null;
     }

     @Nullable
     private String assertViewEvent(@NonNull ContentCaptureEvent event, @NonNull View expectedView,
             AutofillId expectedParentId, String expectedText) {
         assertEvent(event, expectedView, expectedParentId, expectedText);
         return null;
     }

     private String assertEventId(@NonNull ContentCaptureEvent event, View expectedView) {
         final ViewNode node = event.getViewNode();

         if (node == null) {
             return String.format("node is null at %s", event);
         }

         if (expectedView != null && !node.getAutofillId().equals(expectedView.getAutofillId())) {
             return String.format("wrong event id (expected %s, actual is %s) at %s",
                     expectedView.getAutofillId(), node.getAutofillId(), event);
         }
         return null;
     }

     private String assertEventText(@NonNull ContentCaptureEvent event, String expectedText) {
         final ViewNode node = event.getViewNode();
         if (node == null) {
             return String.format("node is null at %s", event);
         }

         if (!TextUtils.equals(node.getText(), expectedText)) {
             return String.format("wrong event text (expected %s, actual is %s) at %s",
                     expectedText, node.getText(), event);
         }
         return null;
     }

     private void assertEvent(@NonNull ContentCaptureEvent event, @Nullable View expectedView,
             @Nullable AutofillId expectedParentId, @Nullable String expectedText) {
         final ViewNode node = event.getViewNode();

         assertThat(node).isNotNull();
         assertWithMessage("wrong class on %s", event).that(node.getClassName())
                 .isEqualTo(expectedView.getClass().getName());
         assertWithMessage("wrong autofill id on %s", event).that(node.getAutofillId())
                 .isEqualTo(expectedView.getAutofillId());

         if (expectedParentId != null) {
             assertWithMessage("wrong parent autofill id on %s", event)
                     .that(node.getParentAutofillId()).isEqualTo(expectedParentId);
         }

         if (expectedText != null) {
             assertWithMessage("wrong text on %s", event).that(node.getText().toString())
                     .isEqualTo(expectedText);
         }
     }

     @Nullable
     private String assertSessionLevelEvent(@NonNull ContentCaptureEvent event) {
         assertWithMessage("event %s should not have a ViewNode", event)
                 .that(event.getViewNode()).isNull();
         assertWithMessage("event %s should not have text", event)
                 .that(event.getText()).isNull();
         assertWithMessage("event %s should not have an autofillId", event)
                 .that(event.getId()).isNull();
         assertWithMessage("event %s should not have autofillIds", event)
                 .that(event.getIds()).isNull();
         return null;
     }

     private void assertNextEvent(@NonNull EventAssertion assertion, int expectedType,
             @NonNull String errorFormat, @Nullable Object... errorArgs) {
         if (mNextEvent >= mEvents.size()) {
             throw new AssertionError("Reached the end of the events: "
                     + String.format(errorFormat, errorArgs) + "\n. Events("
                     + mEvents.size() + "): " + mEvents);
         }
         do {
             final int index = mNextEvent++;
             final ContentCaptureEvent event = mEvents.get(index);
             if (event.getType() != expectedType) {
                 Log.w(TAG, "assertNextEvent(): ignoring event #" + index + "(" + event + ")");
                 continue;
             }
             // If returns an error message from getErrorMessage(), means the error can be ignored.
             // The test will assert nex event.
             // If directly throws AssertionError or exception, means the error cannot be ignored.
             // The test will stop immediately.
             final String error = assertion.getErrorMessage(event);
             if (error == null) {
                 Log.d(TAG, "assertNextEvent(): match event in #" + index + ".");
                 return;
             }
             Log.w(TAG, "assertNextEvent(): ignoring event #" + index + "(" + event + "): "
                     + error);
         } while (mNextEvent < mEvents.size());
         throw new AssertionError(String.format(errorFormat, errorArgs) + "\n. Events("
                 + mEvents.size() + "): " + mEvents);
     }

     private interface EventAssertion {
         @Nullable
         String getErrorMessage(@NonNull ContentCaptureEvent event);
     }
 }
	/*
	* Copyright (C) 2021 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package android.contentcaptureservice.cts;

	import static android.contentcaptureservice.cts.Assertions.assertSessionId;

	import static com.google.common.truth.Truth.assertThat;
	import static com.google.common.truth.Truth.assertWithMessage;

	import android.text.TextUtils;
	import android.util.Log;
	import android.view.View;
	import android.view.autofill.AutofillId;
	import android.view.contentcapture.ContentCaptureEvent;
	import android.view.contentcapture.ContentCaptureSession;
	import android.view.contentcapture.ContentCaptureSessionId;
	import android.view.contentcapture.ViewNode;

	import androidx.annotation.NonNull;
	import androidx.annotation.Nullable;

	import java.util.Arrays;
	import java.util.Collections;
	import java.util.List;

	/**
	* Used to assert Content Capture events by the event order.
	*
	* When the type is the same, the assertor will assert the content of the event.
	* If the current event is different type, this event will be skipped, and then
	* try to assert the next event. Through all events, the assertor will report an
	* "not found" error.
	*/
	public class EventsAssertor {
	private static final String TAG = "CtsContentCapture";
	private final List<ContentCaptureEvent> mEvents;
	private int mNextEvent = 0;

	public EventsAssertor(@NonNull List<ContentCaptureEvent> events) {
	mEvents = Collections.unmodifiableList(events);
	}

	@NonNull
	public EventsAssertor isAtLeast(int size) {
	assertThat(mEvents.size()).isAtLeast(size);
	return this;
	}

	/**
	* Asserts the contents of a {@link ContentCaptureEvent#TYPE_SESSION_RESUMED} event.
	*/
	@NonNull
	public EventsAssertor assertSessionResumed() {
	assertNextEvent((event) -> assertSessionLevelEvent(event),
	ContentCaptureEvent.TYPE_SESSION_RESUMED, "no SESSION_RESUMED event");
	return this;
	}

	/**
	* Asserts the contents of a {@link ContentCaptureEvent#TYPE_SESSION_PAUSED} event.
	*/
	@NonNull
	public EventsAssertor assertSessionPaused() {
	assertNextEvent((event) -> assertSessionLevelEvent(event),
	ContentCaptureEvent.TYPE_SESSION_PAUSED, "no SESSION_PAUSED event");
	return this;
	}

	/**
	* Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_TREE_APPEARING} event.
	*/
	@NonNull
	public EventsAssertor assertViewTreeStarted() {
	assertNextEvent((event) -> assertSessionLevelEvent(event),
	ContentCaptureEvent.TYPE_VIEW_TREE_APPEARING, "no VIEW_TREE_APPEARING event");
	return this;
	}

	/**
	* Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_TREE_APPEARED} event.
	*/
	@NonNull
	public EventsAssertor assertViewTreeFinished() {
	assertNextEvent((event) -> assertSessionLevelEvent(event),
	ContentCaptureEvent.TYPE_VIEW_TREE_APPEARED,
	"no VIEW_TREE_APPEARED event");
	return this;
	}

	/**
	* Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_APPEARED}
	* event for a decor view.
	*
	* <P>The decor view is typically internal, so there isn't much we can assert,
	* other than its autofill id.
	*/
	@NonNull
	public EventsAssertor assertDecorViewAppeared(@NonNull View expectedDecorView) {
	assertNextEvent((event) -> assertEventId(event, expectedDecorView),
	ContentCaptureEvent.TYPE_VIEW_APPEARED,
	"no VIEW_APPEARED event for decor view");
	return this;
	}

	/**
	* Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_APPEARED}
	* event, without checking for parent id.
	*/
	@NonNull
	public EventsAssertor assertViewAppeared(@NonNull View expectedView) {
	assertNextEvent((event) -> assertViewEvent(event, expectedView),
	ContentCaptureEvent.TYPE_VIEW_APPEARED,
	String.format("no VIEW_APPEARED event for %s", expectedView));
	return this;
	}

	/**
	* Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_APPEARED} event.
	*/
	@NonNull
	public EventsAssertor assertViewAppeared(@NonNull View expectedView,
	@NonNull AutofillId expectedParentId) {
	assertNextEvent((event) -> assertViewEvent(event, expectedView, expectedParentId),
	ContentCaptureEvent.TYPE_VIEW_APPEARED,
	String.format("no VIEW_APPEARED event for %s", expectedView));
	return this;
	}

	/**
	* Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_APPEARED} event.
	*/
	@NonNull
	public EventsAssertor assertViewAppeared(@NonNull ContentCaptureSessionId expectedSessionId,
	@NonNull View expectedView, @NonNull AutofillId expectedParentId) {
	assertViewAppeared(expectedView, expectedParentId);
	assertSessionId(expectedSessionId, expectedView);
	return this;
	}


	/**
	* Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_APPEARED} event.
	*/
	@NonNull
	public EventsAssertor assertViewAppeared(@NonNull ContentCaptureSessionId expectedSessionId,
	@NonNull View expectedView) {
	assertViewAppeared(expectedView);
	assertSessionId(expectedSessionId, expectedView);
	return this;
	}

	/**
	* Asserts the {@code text} of a {@link ContentCaptureEvent#TYPE_VIEW_APPEARED}
	* event.
	*/
	@NonNull
	public EventsAssertor assertViewAppeared(@NonNull String text) {
	assertNextEvent((event) -> assertEventText(event, text),
	ContentCaptureEvent.TYPE_VIEW_APPEARED,
	String.format("no TYPE_VIEW_APPEARED event with text: %s", text));
	return this;
	}

	/**
	* Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_DISAPPEARED}
	* event for multiple views.
	*/
	@NonNull
	public EventsAssertor assertViewDisappeared(@NonNull AutofillId autofillId) {
	assertNextEvent((event) -> assertDisappearedEvent(event, autofillId),
	ContentCaptureEvent.TYPE_VIEW_DISAPPEARED,
	String.format("no VIEW_DISAPPEARED event for %s", autofillId));
	return this;
	}

	/**
	* Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_DISAPPEARED}
	* event for multiple views.
	*/
	@NonNull
	public EventsAssertor assertViewDisappeared(@NonNull AutofillId... autofillIds) {
	assertNextEvent((event) -> assertDisappearedEvent(event, autofillIds),
	ContentCaptureEvent.TYPE_VIEW_DISAPPEARED,
	String.format("no VIEW_DISAPPEARED event for %s", Arrays.toString(autofillIds)));
	return this;
	}

	/**
	* Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_TEXT_CHANGED} event.
	*/
	@NonNull
	public EventsAssertor assertViewTextChanged(@NonNull AutofillId expectedId,
	@NonNull String expectedText) {
	assertNextEvent((event) -> assertTextChangedEvent(event, expectedId, expectedText),
	ContentCaptureEvent.TYPE_VIEW_TEXT_CHANGED,
	String.format("no VIEW_TEXT_CHANGED event for %s", expectedId));
	return this;
	}

	/**
	* Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_APPEARED}
	* event for a virtual node.
	*/
	@NonNull
	public EventsAssertor assertVirtualViewAppeared(@NonNull ContentCaptureSession session,
	@NonNull AutofillId parentId, int childId, String expectedText) {
	final AutofillId expectedId = session.newAutofillId(parentId, childId);
	assertNextEvent((event) -> assertVirtualViewEvent(event, expectedId, expectedText),
	ContentCaptureEvent.TYPE_VIEW_APPEARED,
	String.format("no VIEW_APPEARED event for %s", expectedId.toString()));
	return this;
	}

	/**
	* Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_DISAPPEARED}
	* event for a virtual node.
	*/
	@NonNull
	public EventsAssertor assertVirtualViewDisappeared(AutofillId parentId,
	ContentCaptureSession session, int childId) {
	return assertViewDisappeared(session.newAutofillId(parentId, childId));
	}

	/**
	* Asserts the contents of a {@link ContentCaptureEvent#TYPE_VIEW_DISAPPEARED}
	* event for many virtual nodes.
	*/
	@NonNull
	public EventsAssertor assertVirtualViewsDisappeared(AutofillId parentId,
	ContentCaptureSession session, int... childId) {
	final AutofillId[] ids = new AutofillId[childId.length];
	for (int i = 0; i < childId.length; i++) {
	ids[i] = session.newAutofillId(parentId, childId[i]);
	}
	return assertViewDisappeared(ids);
	}

	@Nullable
	private String assertVirtualViewEvent(@NonNull ContentCaptureEvent event,
	@NonNull AutofillId expectedId, @Nullable String expectedText) {
	final ViewNode node = event.getViewNode();
	assertThat(node).isNotNull();
	if (!node.getAutofillId().equals(expectedId)) {
	return String.format("wrong autofill id (expected %s, actual is %s) at %s",
	expectedId, node.getAutofillId(), event);
	}
	if (expectedText != null && node.getText() != null) {
	assertWithMessage("wrong text on %s", event)
	.that(node.getText().toString()).isEqualTo(expectedText);
	} else {
	assertWithMessage("%s should not have text", node)
	.that(node.getText()).isNull();
	}
	return null;
	}

	@Nullable
	private String assertDisappearedEvent(@NonNull ContentCaptureEvent event,
	@NonNull AutofillId expectedId) {
	assertCommonViewDisappearedProperties(event);
	assertWithMessage("wrong autofillId on event %s", event)
	.that(event.getId()).isEqualTo(expectedId);
	assertWithMessage("event %s should not have autofillIds", event)
	.that(event.getIds()).isNull();
	return null;
	}

	@Nullable
	private String assertDisappearedEvent(@NonNull ContentCaptureEvent event,
	@NonNull AutofillId[] expectedIds) {
	final List<AutofillId> ids = event.getIds();

	assertCommonViewDisappearedProperties(event);
	assertWithMessage("no autofillIds on event %s", event).that(ids)
	.isNotNull();
	assertWithMessage("wrong autofillId on event %s", event)
	.that(ids).containsExactly((Object[]) expectedIds).inOrder();
	assertWithMessage("event %s should not have autofillId", event)
	.that(event.getId()).isNull();
	return null;
	}

	@Nullable
	private String assertTextChangedEvent(@NonNull ContentCaptureEvent event,
	@NonNull AutofillId expectedId, @NonNull String expectedText) {
	assertWithMessage("Wrong id on %s", event).that(event.getId())
	.isEqualTo(expectedId);
	assertWithMessage("Wrong text on %s", event).that(event.getText().toString())
	.isEqualTo(expectedText);
	return null;
	}

	private void assertCommonViewDisappearedProperties(@NonNull ContentCaptureEvent event) {
	assertWithMessage("event %s should not have a ViewNode", event)
	.that(event.getViewNode()).isNull();
	assertWithMessage("event %s should not have text", event)
	.that(event.getText()).isNull();
	}

	@Nullable
	private String assertViewEvent(@NonNull ContentCaptureEvent event, @NonNull View expectedView) {
	return assertViewEvent(event, expectedView, /* expectedParentId */ null);
	}

	@Nullable
	private String assertViewEvent(@NonNull ContentCaptureEvent event, @NonNull View expectedView,
	@Nullable AutofillId expectedParentId) {
	assertEvent(event, expectedView, expectedParentId, /* expectedText */ null);
	return null;
	}

	@Nullable
	private String assertViewEvent(@NonNull ContentCaptureEvent event, @NonNull View expectedView,
	AutofillId expectedParentId, String expectedText) {
	assertEvent(event, expectedView, expectedParentId, expectedText);
	return null;
	}

	private String assertEventId(@NonNull ContentCaptureEvent event, View expectedView) {
	final ViewNode node = event.getViewNode();

	if (node == null) {
	return String.format("node is null at %s", event);
	}

	if (expectedView != null && !node.getAutofillId().equals(expectedView.getAutofillId())) {
	return String.format("wrong event id (expected %s, actual is %s) at %s",
	expectedView.getAutofillId(), node.getAutofillId(), event);
	}
	return null;
	}

	private String assertEventText(@NonNull ContentCaptureEvent event, String expectedText) {
	final ViewNode node = event.getViewNode();
	if (node == null) {
	return String.format("node is null at %s", event);
	}

	if (!TextUtils.equals(node.getText(), expectedText)) {
	return String.format("wrong event text (expected %s, actual is %s) at %s",
	expectedText, node.getText(), event);
	}
	return null;
	}

	private void assertEvent(@NonNull ContentCaptureEvent event, @Nullable View expectedView,
	@Nullable AutofillId expectedParentId, @Nullable String expectedText) {
	final ViewNode node = event.getViewNode();

	assertThat(node).isNotNull();
	assertWithMessage("wrong class on %s", event).that(node.getClassName())
	.isEqualTo(expectedView.getClass().getName());
	assertWithMessage("wrong autofill id on %s", event).that(node.getAutofillId())
	.isEqualTo(expectedView.getAutofillId());

	if (expectedParentId != null) {
	assertWithMessage("wrong parent autofill id on %s", event)
	.that(node.getParentAutofillId()).isEqualTo(expectedParentId);
	}

	if (expectedText != null) {
	assertWithMessage("wrong text on %s", event).that(node.getText().toString())
	.isEqualTo(expectedText);
	}
	}

	@Nullable
	private String assertSessionLevelEvent(@NonNull ContentCaptureEvent event) {
	assertWithMessage("event %s should not have a ViewNode", event)
	.that(event.getViewNode()).isNull();
	assertWithMessage("event %s should not have text", event)
	.that(event.getText()).isNull();
	assertWithMessage("event %s should not have an autofillId", event)
	.that(event.getId()).isNull();
	assertWithMessage("event %s should not have autofillIds", event)
	.that(event.getIds()).isNull();
	return null;
	}

	private void assertNextEvent(@NonNull EventAssertion assertion, int expectedType,
	@NonNull String errorFormat, @Nullable Object... errorArgs) {
	if (mNextEvent >= mEvents.size()) {
	throw new AssertionError("Reached the end of the events: "
	+ String.format(errorFormat, errorArgs) + "\n. Events("
	+ mEvents.size() + "): " + mEvents);
	}
	do {
	final int index = mNextEvent++;
	final ContentCaptureEvent event = mEvents.get(index);
	if (event.getType() != expectedType) {
	Log.w(TAG, "assertNextEvent(): ignoring event #" + index + "(" + event + ")");
	continue;
	}
	// If returns an error message from getErrorMessage(), means the error can be ignored.
	// The test will assert nex event.
	// If directly throws AssertionError or exception, means the error cannot be ignored.
	// The test will stop immediately.
	final String error = assertion.getErrorMessage(event);
	if (error == null) {
	Log.d(TAG, "assertNextEvent(): match event in #" + index + ".");
	return;
	}
	Log.w(TAG, "assertNextEvent(): ignoring event #" + index + "(" + event + "): "
	+ error);
	} while (mNextEvent < mEvents.size());
	throw new AssertionError(String.format(errorFormat, errorArgs) + "\n. Events("
	+ mEvents.size() + "): " + mEvents);
	}

	private interface EventAssertion {
	@Nullable
	String getErrorMessage(@NonNull ContentCaptureEvent event);
	}
	}