Merge "Flicker in Fingerprint Enrollment" into tm-qpr-dev
diff --git a/res/values/arrays.xml b/res/values/arrays.xml
index 73de183..42d60ee 100644
--- a/res/values/arrays.xml
+++ b/res/values/arrays.xml
@@ -1664,9 +1664,4 @@
          [CHAR LIMIT=NONE] -->
     <string-array name="allowlist_hide_summary_in_battery_usage" translatable="false">
     </string-array>
-
-    <!-- Array containing help message codes that should not be displayed
-         during fingerprint enrollment. -->
-    <integer-array name="fingerprint_acquired_ignore_list">
-    </integer-array>
 </resources>
diff --git a/res/values/config.xml b/res/values/config.xml
index 2d04bc9..e3b8618 100755
--- a/res/values/config.xml
+++ b/res/values/config.xml
@@ -645,4 +645,11 @@
 
     <!-- Whether the toggle for Auto-rotate with Face Detection should be shown. -->
     <bool name="config_auto_rotate_face_detection_available">true</bool>
+    <!-- In the case of receiving both help and progress message, display progress message. -->
+    <bool name="enrollment_progress_priority_over_help">false</bool>
+    <!-- Prioritize help message by their occurrence -->
+    <bool name="enrollment_prioritize_acquire_messages">false</bool>
+    <!-- Control messages displayed during enrollment -->
+    <bool name="enrollment_message_display_controller_flag">false</bool>
+
 </resources>
diff --git a/res/values/integers.xml b/res/values/integers.xml
index d110de2..530f987 100644
--- a/res/values/integers.xml
+++ b/res/values/integers.xml
@@ -26,4 +26,11 @@
     <integer name="suw_max_faces_enrollable">1</integer>
     <!-- Controls the maximum number of fingerprints enrollable during SUW -->
     <integer name="suw_max_fingerprints_enrollable">1</integer>
+
+    <!-- Minimum display time (in millis) for help messages in fingerprint enrollment. -->
+    <integer name="enrollment_help_minimum_time_display">0</integer>
+    <!-- Minimum display time (in millis) for progress messages in fingerprint enrollment. -->
+    <integer name="enrollment_progress_minimum_time_display">0</integer>
+    <!-- The time (in millis) to wait to collect messages in fingerprint enrollment before displaying it. -->
+    <integer name="enrollment_collect_time">0</integer>
 </resources>
diff --git a/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollEnrolling.java b/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollEnrolling.java
index 897e290..2eadc33 100644
--- a/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollEnrolling.java
+++ b/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollEnrolling.java
@@ -350,8 +350,8 @@
 
     @Override
     protected BiometricEnrollSidecar getSidecar() {
-        final FingerprintEnrollSidecar sidecar = new FingerprintEnrollSidecar();
-        sidecar.setEnrollReason(FingerprintManager.ENROLL_ENROLL);
+        final FingerprintEnrollSidecar sidecar = new FingerprintEnrollSidecar(this,
+                FingerprintManager.ENROLL_ENROLL);
         return sidecar;
     }
 
diff --git a/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollFindSensor.java b/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollFindSensor.java
index 200b8c5..778ee5c 100644
--- a/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollFindSensor.java
+++ b/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollFindSensor.java
@@ -293,8 +293,8 @@
         mSidecar = (FingerprintEnrollSidecar) getSupportFragmentManager().findFragmentByTag(
                 FingerprintEnrollEnrolling.TAG_SIDECAR);
         if (mSidecar == null) {
-            mSidecar = new FingerprintEnrollSidecar();
-            mSidecar.setEnrollReason(FingerprintManager.ENROLL_FIND_SENSOR);
+            mSidecar = new FingerprintEnrollSidecar(this,
+                    FingerprintManager.ENROLL_FIND_SENSOR);
             getSupportFragmentManager().beginTransaction()
                     .add(mSidecar, FingerprintEnrollEnrolling.TAG_SIDECAR)
                     .commitAllowingStateLoss();
diff --git a/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollSidecar.java b/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollSidecar.java
index d1e512e..b3b9975 100644
--- a/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollSidecar.java
+++ b/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollSidecar.java
@@ -16,19 +16,19 @@
 
 package com.android.settings.biometrics.fingerprint;
 
+import static android.hardware.fingerprint.FingerprintManager.ENROLL_ENROLL;
+
 import android.app.Activity;
 import android.app.settings.SettingsEnums;
+import android.content.Context;
 import android.hardware.fingerprint.FingerprintManager;
+import android.os.SystemClock;
 import android.util.Log;
 
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.settings.R;
 import com.android.settings.biometrics.BiometricEnrollSidecar;
 
-import java.util.Collections;
-import java.util.HashSet;
-import java.util.Set;
-
 /**
  * Sidecar fragment to handle the state around fingerprint enrollment.
  */
@@ -37,19 +37,41 @@
 
     private FingerprintUpdater mFingerprintUpdater;
     private @FingerprintManager.EnrollReason int mEnrollReason;
-    private Set<Integer> mHelpIgnore;
+    private final MessageDisplayController mMessageDisplayController;
+    private final boolean mMessageDisplayControllerFlag;
+
+    /**
+     * Create a new FingerprintEnrollSidecar object.
+     * @param context associated context
+     * @param enrollReason reason for enrollment
+     */
+    public FingerprintEnrollSidecar(Context context,
+            @FingerprintManager.EnrollReason int enrollReason) {
+        mEnrollReason = enrollReason;
+
+        int helpMinimumDisplayTime = context.getResources().getInteger(
+                R.integer.enrollment_help_minimum_time_display);
+        int progressMinimumDisplayTime = context.getResources().getInteger(
+                R.integer.enrollment_progress_minimum_time_display);
+        boolean progressPriorityOverHelp = context.getResources().getBoolean(
+                R.bool.enrollment_progress_priority_over_help);
+        boolean prioritizeAcquireMessages = context.getResources().getBoolean(
+                R.bool.enrollment_prioritize_acquire_messages);
+        int collectTime = context.getResources().getInteger(
+                R.integer.enrollment_collect_time);
+        mMessageDisplayControllerFlag = context.getResources().getBoolean(
+                R.bool.enrollment_message_display_controller_flag);
+
+        mMessageDisplayController = new MessageDisplayController(context.getMainThreadHandler(),
+                mEnrollmentCallback, SystemClock.elapsedRealtimeClock(), helpMinimumDisplayTime,
+                progressMinimumDisplayTime, progressPriorityOverHelp, prioritizeAcquireMessages,
+                collectTime);
+    }
 
     @Override
     public void onAttach(Activity activity) {
         super.onAttach(activity);
         mFingerprintUpdater = new FingerprintUpdater(activity);
-        final int[] ignoreAcquiredInfo = getResources().getIntArray(
-                R.array.fingerprint_acquired_ignore_list);
-        mHelpIgnore = new HashSet<>();
-        for (int acquiredInfo: ignoreAcquiredInfo) {
-            mHelpIgnore.add(acquiredInfo);
-        }
-        mHelpIgnore = Collections.unmodifiableSet(mHelpIgnore);
     }
 
     @Override
@@ -62,8 +84,16 @@
                     getString(R.string.fingerprint_intro_error_unknown));
             return;
         }
-        mFingerprintUpdater.enroll(mToken, mEnrollmentCancel, mUserId, mEnrollmentCallback,
-                mEnrollReason);
+
+        if (mEnrollReason == ENROLL_ENROLL && mMessageDisplayControllerFlag) {
+            //API calls need to be processed for {@link FingerprintEnrollEnrolling}
+            mFingerprintUpdater.enroll(mToken, mEnrollmentCancel, mUserId,
+                    mMessageDisplayController, mEnrollReason);
+        } else {
+            //No processing required for {@link FingerprintEnrollFindSensor}
+            mFingerprintUpdater.enroll(mToken, mEnrollmentCancel, mUserId, mEnrollmentCallback,
+                    mEnrollReason);
+        }
     }
 
     public void setEnrollReason(@FingerprintManager.EnrollReason int enrollReason) {
@@ -80,9 +110,6 @@
 
         @Override
         public void onEnrollmentHelp(int helpMsgId, CharSequence helpString) {
-            if (mHelpIgnore.contains(helpMsgId)) {
-                return;
-            }
             FingerprintEnrollSidecar.super.onEnrollmentHelp(helpMsgId, helpString);
         }
 
diff --git a/src/com/android/settings/biometrics/fingerprint/MessageDisplayController.java b/src/com/android/settings/biometrics/fingerprint/MessageDisplayController.java
new file mode 100644
index 0000000..11f3ee3
--- /dev/null
+++ b/src/com/android/settings/biometrics/fingerprint/MessageDisplayController.java
@@ -0,0 +1,264 @@
+/*
+ * Copyright (C) 2022 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 com.android.settings.biometrics.fingerprint;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.hardware.fingerprint.FingerprintManager;
+import android.os.Handler;
+
+import java.time.Clock;
+import java.util.ArrayDeque;
+import java.util.Deque;
+import java.util.HashMap;
+
+/**
+ * Processes message provided from the enrollment callback and filters them based
+ * on the below configurable flags. This is primarily used to reduce the rate
+ * at which messages come through, which in turns eliminates UI flicker.
+ */
+public class MessageDisplayController extends FingerprintManager.EnrollmentCallback {
+
+    private final int mHelpMinimumDisplayTime;
+    private final int mProgressMinimumDisplayTime;
+    private final boolean mProgressPriorityOverHelp;
+    private final boolean mPrioritizeAcquireMessages;
+    private final int mCollectTime;
+    @NonNull
+    private final Deque<HelpMessage> mHelpMessageList;
+    @NonNull
+    private final Deque<ProgressMessage> mProgressMessageList;
+    @NonNull
+    private final Handler mHandler;
+    @NonNull
+    private final Clock mClock;
+    @NonNull
+    private final Runnable mDisplayMessageRunnable;
+
+    @Nullable
+    private ProgressMessage mLastProgressMessageDisplayed;
+    private boolean mMustDisplayProgress;
+    private boolean mWaitingForMessage;
+    @NonNull FingerprintManager.EnrollmentCallback mEnrollmentCallback;
+
+    private abstract static class Message {
+        long mTimeStamp = 0;
+        abstract void display();
+    }
+
+    private class HelpMessage extends Message {
+        private final int mHelpMsgId;
+        private final CharSequence mHelpString;
+
+        HelpMessage(int helpMsgId, CharSequence helpString) {
+            mHelpMsgId = helpMsgId;
+            mHelpString = helpString;
+            mTimeStamp = mClock.millis();
+        }
+
+        @Override
+        void display() {
+            mEnrollmentCallback.onEnrollmentHelp(mHelpMsgId, mHelpString);
+            mHandler.postDelayed(mDisplayMessageRunnable, mHelpMinimumDisplayTime);
+        }
+    }
+
+    private class ProgressMessage extends Message {
+        private final int mRemaining;
+
+        ProgressMessage(int remaining) {
+            mRemaining = remaining;
+            mTimeStamp = mClock.millis();
+        }
+
+        @Override
+        void display() {
+            mEnrollmentCallback.onEnrollmentProgress(mRemaining);
+            mLastProgressMessageDisplayed = this;
+            mHandler.postDelayed(mDisplayMessageRunnable, mProgressMinimumDisplayTime);
+        }
+    }
+
+    /**
+     * Creating a MessageDisplayController object.
+     * @param handler main handler to run message queue
+     * @param enrollmentCallback callback to display messages
+     * @param clock real time system clock
+     * @param helpMinimumDisplayTime the minimum duration (in millis) that
+*        a help message needs to be displayed for
+     * @param progressMinimumDisplayTime the minimum duration (in millis) that
+*        a progress message needs to be displayed for
+     * @param progressPriorityOverHelp if true, then progress message is displayed
+*        when both help and progress message APIs have been called
+     * @param prioritizeAcquireMessages if true, then displays the help message
+*        which has occurred the most after the last display message
+     * @param collectTime the waiting time (in millis) to collect messages when it is idle
+     */
+    public MessageDisplayController(@NonNull Handler handler,
+            FingerprintManager.EnrollmentCallback enrollmentCallback,
+            @NonNull Clock clock, int helpMinimumDisplayTime, int progressMinimumDisplayTime,
+            boolean progressPriorityOverHelp, boolean prioritizeAcquireMessages,
+            int collectTime) {
+        mClock = clock;
+        mWaitingForMessage = false;
+        mHelpMessageList = new ArrayDeque<>();
+        mProgressMessageList = new ArrayDeque<>();
+        mHandler = handler;
+        mEnrollmentCallback = enrollmentCallback;
+
+        mHelpMinimumDisplayTime = helpMinimumDisplayTime;
+        mProgressMinimumDisplayTime = progressMinimumDisplayTime;
+        mProgressPriorityOverHelp = progressPriorityOverHelp;
+        mPrioritizeAcquireMessages = prioritizeAcquireMessages;
+        mCollectTime = collectTime;
+
+        mDisplayMessageRunnable = () -> {
+            long timeStamp = mClock.millis();
+            Message messageToDisplay = getMessageToDisplay(timeStamp);
+
+            if (messageToDisplay != null) {
+                messageToDisplay.display();
+            } else {
+                mWaitingForMessage = true;
+            }
+        };
+
+        mHandler.postDelayed(mDisplayMessageRunnable, 0);
+    }
+
+    /**
+     * Adds help message to the queue to be processed later.
+     *
+     * @param helpMsgId message Id associated with the help message
+     * @param helpString string associated with the help message
+     */
+    @Override
+    public void onEnrollmentHelp(int helpMsgId, CharSequence helpString) {
+        mHelpMessageList.add(new HelpMessage(helpMsgId, helpString));
+
+        if (mWaitingForMessage) {
+            mWaitingForMessage = false;
+            mHandler.postDelayed(mDisplayMessageRunnable, mCollectTime);
+        }
+    }
+
+    /**
+     * Adds progress change message to the queue to be processed later.
+     *
+     * @param remaining remaining number of steps to complete enrollment
+     */
+    @Override
+    public void onEnrollmentProgress(int remaining) {
+        mProgressMessageList.add(new ProgressMessage(remaining));
+
+        if (mWaitingForMessage) {
+            mWaitingForMessage = false;
+            mHandler.postDelayed(mDisplayMessageRunnable, mCollectTime);
+        }
+    }
+
+    @Override
+    public void onEnrollmentError(int errMsgId, CharSequence errString) {
+        mEnrollmentCallback.onEnrollmentError(errMsgId, errString);
+    }
+
+    private Message getMessageToDisplay(long timeStamp) {
+        ProgressMessage progressMessageToDisplay = getProgressMessageToDisplay(timeStamp);
+        if (mMustDisplayProgress) {
+            mMustDisplayProgress = false;
+            if (progressMessageToDisplay != null) {
+                return progressMessageToDisplay;
+            }
+            if (mLastProgressMessageDisplayed != null) {
+                return mLastProgressMessageDisplayed;
+            }
+        }
+
+        Message helpMessageToDisplay = getHelpMessageToDisplay(timeStamp);
+        if (helpMessageToDisplay != null || progressMessageToDisplay != null) {
+            if (mProgressPriorityOverHelp && progressMessageToDisplay != null) {
+                return progressMessageToDisplay;
+            } else if (helpMessageToDisplay != null) {
+                if (progressMessageToDisplay != null) {
+                    mMustDisplayProgress = true;
+                    mLastProgressMessageDisplayed = progressMessageToDisplay;
+                }
+                return helpMessageToDisplay;
+            } else {
+                return progressMessageToDisplay;
+            }
+        } else {
+            return null;
+        }
+    }
+
+    private ProgressMessage getProgressMessageToDisplay(long timeStamp) {
+        ProgressMessage finalProgressMessage = null;
+        while (mProgressMessageList != null && !mProgressMessageList.isEmpty()) {
+            Message message = mProgressMessageList.peekFirst();
+            if (message.mTimeStamp <= timeStamp) {
+                ProgressMessage progressMessage = mProgressMessageList.pollFirst();
+                if (mLastProgressMessageDisplayed != null
+                        && mLastProgressMessageDisplayed.mRemaining == progressMessage.mRemaining) {
+                    continue;
+                }
+                finalProgressMessage = progressMessage;
+            } else {
+                break;
+            }
+        }
+
+        return finalProgressMessage;
+    }
+
+    private HelpMessage getHelpMessageToDisplay(long timeStamp) {
+        HashMap<CharSequence, Integer> messageCount = new HashMap<>();
+        HelpMessage finalHelpMessage = null;
+
+        while (mHelpMessageList != null && !mHelpMessageList.isEmpty()) {
+            Message message = mHelpMessageList.peekFirst();
+            if (message.mTimeStamp <= timeStamp) {
+                finalHelpMessage = mHelpMessageList.pollFirst();
+                CharSequence errString = finalHelpMessage.mHelpString;
+                messageCount.put(errString, messageCount.getOrDefault(errString, 0) + 1);
+            } else {
+                break;
+            }
+        }
+        if (mPrioritizeAcquireMessages) {
+            finalHelpMessage = prioritizeHelpMessageByCount(messageCount);
+        }
+
+        return finalHelpMessage;
+    }
+
+    private HelpMessage prioritizeHelpMessageByCount(HashMap<CharSequence, Integer> messageCount) {
+        int maxCount = 0;
+        CharSequence maxCountMessage = null;
+
+        for (CharSequence key :
+                messageCount.keySet()) {
+            if (maxCount < messageCount.get(key)) {
+                maxCountMessage = key;
+                maxCount = messageCount.get(key);
+            }
+        }
+
+        return maxCountMessage != null ? new HelpMessage(0 /* errMsgId */,
+                maxCountMessage) : null;
+    }
+}
diff --git a/tests/robotests/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollEnrollingTest.java b/tests/robotests/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollEnrollingTest.java
index b049b7b..b899206 100644
--- a/tests/robotests/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollEnrollingTest.java
+++ b/tests/robotests/src/com/android/settings/biometrics/fingerprint/FingerprintEnrollEnrollingTest.java
@@ -18,7 +18,6 @@
 
 import static android.hardware.fingerprint.FingerprintSensorProperties.TYPE_POWER_BUTTON;
 import static android.hardware.fingerprint.FingerprintSensorProperties.TYPE_UDFPS_OPTICAL;
-import static android.hardware.fingerprint.FingerprintSensorProperties.TYPE_UNKNOWN;
 
 import static com.android.settings.biometrics.fingerprint.FingerprintEnrollEnrolling.KEY_STATE_PREVIOUS_ROTATION;
 import static com.android.settings.biometrics.fingerprint.FingerprintEnrollEnrolling.SFPS_STAGE_NO_ANIMATION;
@@ -36,8 +35,6 @@
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
-import static org.mockito.Mockito.mock;
-
 
 import android.content.Context;
 import android.content.res.ColorStateList;
@@ -53,9 +50,6 @@
 import android.os.Vibrator;
 import android.view.Display;
 import android.view.Surface;
-import android.widget.TextView;
-
-import androidx.annotation.Nullable;
 
 import com.android.settings.R;
 import com.android.settings.testutils.FakeFeatureFactory;
@@ -104,42 +98,6 @@
     }
 
     @Test
-    public void fingerprintEnrollHelp_shouldShowHelpText() {
-        initializeActivityFor(TYPE_UNKNOWN);
-        TestFingerprintEnrollSidecar sidecar = new TestFingerprintEnrollSidecar();
-        Resources resources = mock(Resources.class);
-        doReturn(resources).when(mContext).getResources();
-        when(resources.getIntArray(R.array.fingerprint_acquired_ignore_list))
-                .thenReturn(new int[]{3});
-
-        sidecar.setListener(mActivity);
-        sidecar.onAttach(mActivity);
-        sidecar.mEnrollmentCallback.onEnrollmentHelp(5,
-                "Help message should be displayed.");
-
-        TextView errorText = mActivity.findViewById(R.id.error_text);
-        assertThat(errorText.getText()).isEqualTo("Help message should be displayed.");
-    }
-
-    @Test
-    public void fingerprintEnrollHelp_shouldNotShowHelpText() {
-        initializeActivityFor(TYPE_UNKNOWN);
-        TestFingerprintEnrollSidecar sidecar = new TestFingerprintEnrollSidecar();
-        Resources resources = mock(Resources.class);
-        doReturn(resources).when(mContext).getResources();
-        when(resources.getIntArray(R.array.fingerprint_acquired_ignore_list))
-                .thenReturn(new int[]{3});
-
-        sidecar.setListener(mActivity);
-        sidecar.onAttach(mActivity);
-        sidecar.mEnrollmentCallback.onEnrollmentHelp(3,
-                "Help message should not be displayed.");
-
-        TextView errorText = mActivity.findViewById(R.id.error_text);
-        assertThat(errorText.getText()).isEqualTo("");
-    }
-
-    @Test
     public void fingerprintUdfpsEnrollSuccessProgress_shouldNotVibrate() {
         initializeActivityFor(TYPE_UDFPS_OPTICAL);
 
@@ -346,12 +304,4 @@
 
         return callbackCaptor.getValue();
     }
-
-    private class TestFingerprintEnrollSidecar extends FingerprintEnrollSidecar {
-        @Nullable
-        @Override
-        public Context getContext() {
-            return mContext;
-        }
-    }
 }
\ No newline at end of file
diff --git a/tests/robotests/src/com/android/settings/biometrics/fingerprint/MessageDisplayControllerTest.java b/tests/robotests/src/com/android/settings/biometrics/fingerprint/MessageDisplayControllerTest.java
new file mode 100644
index 0000000..0fa0918
--- /dev/null
+++ b/tests/robotests/src/com/android/settings/biometrics/fingerprint/MessageDisplayControllerTest.java
@@ -0,0 +1,219 @@
+/*
+ * Copyright (C) 2022 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 com.android.settings.biometrics.fingerprint;
+
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
+
+import android.hardware.fingerprint.FingerprintManager;
+import android.os.Handler;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnit;
+import org.mockito.junit.MockitoRule;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.shadows.ShadowLooper;
+
+import java.time.Clock;
+import java.util.concurrent.TimeUnit;
+
+@RunWith(RobolectricTestRunner.class)
+public class MessageDisplayControllerTest {
+    @Rule
+    public final MockitoRule mockito = MockitoJUnit.rule();
+
+    private static final long START_TIME = 0L;
+    private static final int HELP_ID = 0;
+    private static final String HELP_MESSAGE = "Default Help Message";
+    private static final int REMAINING = 5;
+    private static final int HELP_MINIMUM_DISPLAY_TIME = 300;
+    private static final int PROGRESS_MINIMUM_DISPLAY_TIME = 250;
+    private static final int COLLECT_TIME = 100;
+
+    private MessageDisplayController mMessageDisplayController;
+    @Mock
+    private FingerprintManager.EnrollmentCallback mEnrollmentCallback;
+    @Mock
+    private Clock mClock;
+
+    @Before
+    public void setup() {
+        mMessageDisplayController = new MessageDisplayController(new Handler(), mEnrollmentCallback,
+                mClock,
+                HELP_MINIMUM_DISPLAY_TIME,   /* progressPriorityOverHelp */
+                PROGRESS_MINIMUM_DISPLAY_TIME,   /* prioritizeAcquireMessages */
+                false, false, COLLECT_TIME);
+    }
+
+    private void setMessageDisplayController(boolean progressPriorityOverHelp,
+            boolean prioritizeAcquireMessages) {
+        mMessageDisplayController = new MessageDisplayController(new Handler(), mEnrollmentCallback,
+                mClock, HELP_MINIMUM_DISPLAY_TIME, PROGRESS_MINIMUM_DISPLAY_TIME,
+                progressPriorityOverHelp, prioritizeAcquireMessages, COLLECT_TIME);
+    }
+
+    @Test
+    public void showsHelpMessageAfterCollectTime() {
+        when(mClock.millis()).thenReturn(START_TIME);
+
+        mMessageDisplayController.onEnrollmentHelp(HELP_ID, HELP_MESSAGE);
+        when(mClock.millis()).thenReturn((long) COLLECT_TIME);
+        ShadowLooper.idleMainLooper(COLLECT_TIME, TimeUnit.MILLISECONDS);
+
+        verify(mEnrollmentCallback).onEnrollmentHelp(HELP_ID, HELP_MESSAGE);
+        verifyNoMoreInteractions(mEnrollmentCallback);
+    }
+
+    @Test
+    public void showsProgressMessageAfterCollectTime() {
+        when(mClock.millis()).thenReturn(START_TIME);
+
+        mMessageDisplayController.onEnrollmentProgress(REMAINING);
+        when(mClock.millis()).thenReturn((long) COLLECT_TIME);
+        ShadowLooper.idleMainLooper(COLLECT_TIME, TimeUnit.MILLISECONDS);
+
+        verify(mEnrollmentCallback).onEnrollmentProgress(REMAINING);
+        verifyNoMoreInteractions(mEnrollmentCallback);
+    }
+
+    @Test
+    public void helpDisplayedForMinimumDisplayTime() {
+        when(mClock.millis()).thenReturn(START_TIME);
+
+        mMessageDisplayController.onEnrollmentHelp(HELP_ID, HELP_MESSAGE);
+        when(mClock.millis()).thenReturn((long) COLLECT_TIME);
+        ShadowLooper.idleMainLooper(COLLECT_TIME, TimeUnit.MILLISECONDS);
+
+        verify(mEnrollmentCallback).onEnrollmentHelp(HELP_ID, HELP_MESSAGE);
+
+        mMessageDisplayController.onEnrollmentProgress(REMAINING);
+
+        verifyNoMoreInteractions(mEnrollmentCallback);
+
+        when(mClock.millis()).thenReturn((long) (HELP_MINIMUM_DISPLAY_TIME + COLLECT_TIME));
+        ShadowLooper.idleMainLooper(HELP_MINIMUM_DISPLAY_TIME, TimeUnit.MILLISECONDS);
+
+        verify(mEnrollmentCallback).onEnrollmentProgress(REMAINING);
+    }
+
+    @Test
+    public void progressDisplayedForMinimumDisplayTime() {
+        when(mClock.millis()).thenReturn(START_TIME);
+
+        mMessageDisplayController.onEnrollmentProgress(REMAINING);
+        when(mClock.millis()).thenReturn((long) COLLECT_TIME);
+        ShadowLooper.idleMainLooper(COLLECT_TIME, TimeUnit.MILLISECONDS);
+
+        verify(mEnrollmentCallback).onEnrollmentProgress(REMAINING);
+
+        mMessageDisplayController.onEnrollmentHelp(HELP_ID, HELP_MESSAGE);
+
+        verifyNoMoreInteractions(mEnrollmentCallback);
+
+        when(mClock.millis()).thenReturn((long) (COLLECT_TIME + PROGRESS_MINIMUM_DISPLAY_TIME));
+        ShadowLooper.idleMainLooper(PROGRESS_MINIMUM_DISPLAY_TIME, TimeUnit.MILLISECONDS);
+
+        verify(mEnrollmentCallback).onEnrollmentHelp(HELP_ID, HELP_MESSAGE);
+    }
+
+    @Test
+    public void prioritizeHelpMessage_thenShowProgress() {
+        when(mClock.millis()).thenReturn(START_TIME);
+
+        mMessageDisplayController.onEnrollmentProgress(REMAINING);
+        mMessageDisplayController.onEnrollmentHelp(HELP_ID, HELP_MESSAGE);
+        when(mClock.millis()).thenReturn((long) COLLECT_TIME);
+        ShadowLooper.idleMainLooper(COLLECT_TIME, TimeUnit.MILLISECONDS);
+
+        verify(mEnrollmentCallback).onEnrollmentHelp(HELP_ID, HELP_MESSAGE);
+        verifyNoMoreInteractions(mEnrollmentCallback);
+
+        mMessageDisplayController.onEnrollmentHelp(HELP_ID, HELP_MESSAGE);
+        when(mClock.millis()).thenReturn((long) (COLLECT_TIME + HELP_MINIMUM_DISPLAY_TIME));
+        ShadowLooper.idleMainLooper(HELP_MINIMUM_DISPLAY_TIME, TimeUnit.MILLISECONDS);
+
+        verify(mEnrollmentCallback).onEnrollmentProgress(REMAINING);
+    }
+
+    @Test
+    public void prioritizeProgressOverHelp() {
+        when(mClock.millis()).thenReturn(START_TIME);
+        setMessageDisplayController(true /* progressPriorityOverHelp */,
+                false /* prioritizeAcquireMessages */);
+
+        mMessageDisplayController.onEnrollmentProgress(REMAINING);
+        mMessageDisplayController.onEnrollmentHelp(HELP_ID, HELP_MESSAGE);
+        when(mClock.millis()).thenReturn((long) COLLECT_TIME);
+        ShadowLooper.idleMainLooper(COLLECT_TIME, TimeUnit.MILLISECONDS);
+
+        verify(mEnrollmentCallback).onEnrollmentProgress(REMAINING);
+        verifyNoMoreInteractions(mEnrollmentCallback);
+    }
+
+    @Test
+    public void prioritizeHelpMessageByCount() {
+        String newHelpMessage = "New message";
+        when(mClock.millis()).thenReturn(START_TIME);
+        setMessageDisplayController(false /* progressPriorityOverHelp */,
+                true /* prioritizeAcquireMessages */);
+
+        mMessageDisplayController.onEnrollmentHelp(HELP_ID, HELP_MESSAGE);
+        mMessageDisplayController.onEnrollmentHelp(HELP_ID, HELP_MESSAGE);
+        mMessageDisplayController.onEnrollmentHelp(HELP_ID, newHelpMessage);
+        when(mClock.millis()).thenReturn((long) COLLECT_TIME);
+        ShadowLooper.idleMainLooper(COLLECT_TIME, TimeUnit.MILLISECONDS);
+
+        verify(mEnrollmentCallback).onEnrollmentHelp(HELP_ID, HELP_MESSAGE);
+        verifyNoMoreInteractions(mEnrollmentCallback);
+    }
+
+    @Test
+    public void ignoreSameProgress() {
+        int progressChange = REMAINING - 1;
+        when(mClock.millis()).thenReturn(START_TIME);
+        setMessageDisplayController(true /* progressPriorityOverHelp */,
+                false /* prioritizeAcquireMessages */);
+
+        mMessageDisplayController.onEnrollmentProgress(REMAINING);
+        mMessageDisplayController.onEnrollmentHelp(HELP_ID, HELP_MESSAGE);
+        when(mClock.millis()).thenReturn((long) COLLECT_TIME);
+        ShadowLooper.idleMainLooper(COLLECT_TIME, TimeUnit.MILLISECONDS);
+
+        verify(mEnrollmentCallback).onEnrollmentProgress(REMAINING);
+        verifyNoMoreInteractions(mEnrollmentCallback);
+
+        mMessageDisplayController.onEnrollmentProgress(REMAINING);
+        mMessageDisplayController.onEnrollmentHelp(HELP_ID, HELP_MESSAGE);
+        when(mClock.millis()).thenReturn((long) (COLLECT_TIME + PROGRESS_MINIMUM_DISPLAY_TIME));
+        ShadowLooper.idleMainLooper(PROGRESS_MINIMUM_DISPLAY_TIME, TimeUnit.MILLISECONDS);
+
+        verify(mEnrollmentCallback).onEnrollmentHelp(HELP_ID, HELP_MESSAGE);
+
+        mMessageDisplayController.onEnrollmentProgress(progressChange);
+        mMessageDisplayController.onEnrollmentHelp(HELP_ID, HELP_MESSAGE);
+        when(mClock.millis()).thenReturn((long) (COLLECT_TIME + PROGRESS_MINIMUM_DISPLAY_TIME
+                + HELP_MINIMUM_DISPLAY_TIME));
+        ShadowLooper.idleMainLooper(HELP_MINIMUM_DISPLAY_TIME, TimeUnit.MILLISECONDS);
+
+        verify(mEnrollmentCallback).onEnrollmentProgress(progressChange);
+    }
+}