1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.camera.stress;
18
19import android.app.Instrumentation;
20import android.os.Environment;
21import android.test.ActivityInstrumentationTestCase2;
22import android.test.suitebuilder.annotation.LargeTest;
23import android.util.Log;
24import android.view.KeyEvent;
25import com.android.camera.CameraActivity;
26import java.io.BufferedWriter;
27import java.io.File;
28import java.io.FilenameFilter;
29import java.io.FileWriter;
30import java.io.IOException;
31import java.util.ArrayList;
32
33/**
34 * Junit / Instrumentation test case for measuring camera shot to shot latency
35 */
36public class ShotToShotLatency extends ActivityInstrumentationTestCase2<CameraActivity> {
37    private String TAG = "ShotToShotLatency";
38    private static final int TOTAL_NUMBER_OF_SNAPSHOTS = 250;
39    private static final long SNAPSHOT_WAIT = 1000;
40    private static final String CAMERA_TEST_OUTPUT_FILE =
41            Environment.getExternalStorageDirectory().toString() + "/mediaStressOut.txt";
42    private static final String CAMERA_IMAGE_DIRECTORY =
43            Environment.getExternalStorageDirectory().toString() + "/DCIM/Camera/";
44
45    public ShotToShotLatency() {
46        super(CameraActivity.class);
47    }
48
49    @Override
50    protected void setUp() throws Exception {
51        getActivity();
52        super.setUp();
53    }
54
55    @Override
56    protected void tearDown() throws Exception {
57        super.tearDown();
58    }
59
60    private void cleanupLatencyImages() {
61        try {
62            File sdcard = new File(CAMERA_IMAGE_DIRECTORY);
63            File[] pics = null;
64            FilenameFilter filter = new FilenameFilter() {
65                public boolean accept(File dir, String name) {
66                    return name.endsWith(".jpg");
67                }
68            };
69            pics = sdcard.listFiles(filter);
70            for (File f : pics) {
71                f.delete();
72            }
73        } catch (SecurityException e) {
74            Log.e(TAG, "Security manager access violation: " + e.toString());
75        }
76    }
77
78    private void sleep(long time) {
79        try {
80            Thread.sleep(time);
81        } catch (InterruptedException e) {
82            Log.e(TAG, "Sleep InterruptedException " + e.toString());
83        }
84    }
85
86    public void testShotToShotLatency() {
87        long sigmaOfDiffFromMeanSquared = 0;
88        double mean = 0;
89        double standardDeviation = 0;
90        ArrayList<Long> captureTimes = new ArrayList<Long>();
91        ArrayList<Long> latencyTimes = new ArrayList<Long>();
92
93        Log.v(TAG, "start testShotToShotLatency test");
94        Instrumentation inst = getInstrumentation();
95
96        // Generate data points
97        for (int i = 0; i < TOTAL_NUMBER_OF_SNAPSHOTS; i++) {
98            inst.sendKeyDownUpSync(KeyEvent.KEYCODE_DPAD_CENTER);
99            sleep(SNAPSHOT_WAIT);
100            CameraActivity c = getActivity();
101            if (c.getCaptureStartTime() > 0) {
102                captureTimes.add(c.getCaptureStartTime());
103            }
104        }
105
106        // Calculate latencies
107        for (int j = 1; j < captureTimes.size(); j++) {
108            latencyTimes.add(captureTimes.get(j) - captureTimes.get(j - 1));
109        }
110
111        // Crunch numbers
112        for (long dataPoint : latencyTimes) {
113            mean += (double) dataPoint;
114        }
115        mean /= latencyTimes.size();
116
117        for (long dataPoint : latencyTimes) {
118            sigmaOfDiffFromMeanSquared += (dataPoint - mean) * (dataPoint - mean);
119        }
120        standardDeviation = Math.sqrt(sigmaOfDiffFromMeanSquared / latencyTimes.size());
121
122        // Report statistics
123        File outFile = new File(CAMERA_TEST_OUTPUT_FILE);
124        BufferedWriter output = null;
125        try {
126            output = new BufferedWriter(new FileWriter(outFile, true));
127            output.write("Shot to shot latency - mean: " + mean + "\n");
128            output.write("Shot to shot latency - standard deviation: " + standardDeviation + "\n");
129            cleanupLatencyImages();
130        } catch (IOException e) {
131            Log.e(TAG, "testShotToShotLatency IOException writing to log " + e.toString());
132        } finally {
133            try {
134                if (output != null) {
135                    output.close();
136                }
137            } catch (IOException e) {
138                Log.e(TAG, "Error closing file: " + e.toString());
139            }
140        }
141    }
142}
143