1/*
2 * Copyright (C) 2016 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
17#include <unistd.h>
18#include <utils/SystemClock.h>
19
20#include <gtest/gtest.h>
21
22static const auto MS_IN_NS = 1000000;
23
24static const int64_t SLEEP_MS = 500;
25static const int64_t SLEEP_NS = SLEEP_MS * MS_IN_NS;
26// Conservatively assume that we might be descheduled for up to 50 ms
27static const int64_t SLACK_MS = 50;
28static const int64_t SLACK_NS = SLACK_MS * MS_IN_NS;
29
30TEST(SystemClock, SystemClock) {
31    auto startUptimeMs = android::uptimeMillis();
32    auto startRealtimeMs = android::elapsedRealtime();
33    auto startRealtimeNs = android::elapsedRealtimeNano();
34
35    ASSERT_GT(startUptimeMs, 0)
36            << "uptimeMillis() reported an impossible uptime";
37    ASSERT_GE(startRealtimeMs, startUptimeMs)
38            << "elapsedRealtime() thinks we've suspended for negative time";
39    ASSERT_GE(startRealtimeNs, startUptimeMs * MS_IN_NS)
40            << "elapsedRealtimeNano() thinks we've suspended for negative time";
41
42    ASSERT_GE(startRealtimeNs, startRealtimeMs * MS_IN_NS)
43            << "elapsedRealtime() and elapsedRealtimeNano() are inconsistent";
44    ASSERT_LT(startRealtimeNs, (startRealtimeMs + SLACK_MS) * MS_IN_NS)
45            << "elapsedRealtime() and elapsedRealtimeNano() are inconsistent";
46
47    timespec ts;
48    ts.tv_sec = 0;
49    ts.tv_nsec = SLEEP_MS * MS_IN_NS;
50    auto nanosleepErr = TEMP_FAILURE_RETRY(nanosleep(&ts, nullptr));
51    ASSERT_EQ(nanosleepErr, 0) << "nanosleep() failed: " << strerror(errno);
52
53    auto endUptimeMs = android::uptimeMillis();
54    auto endRealtimeMs = android::elapsedRealtime();
55    auto endRealtimeNs = android::elapsedRealtimeNano();
56
57    EXPECT_GE(endUptimeMs - startUptimeMs, SLEEP_MS)
58            << "uptimeMillis() advanced too little after nanosleep()";
59    EXPECT_LT(endUptimeMs - startUptimeMs, SLEEP_MS + SLACK_MS)
60            << "uptimeMillis() advanced too much after nanosleep()";
61    EXPECT_GE(endRealtimeMs - startRealtimeMs, SLEEP_MS)
62            << "elapsedRealtime() advanced too little after nanosleep()";
63    EXPECT_LT(endRealtimeMs - startRealtimeMs, SLEEP_MS + SLACK_MS)
64            << "elapsedRealtime() advanced too much after nanosleep()";
65    EXPECT_GE(endRealtimeNs - startRealtimeNs, SLEEP_NS)
66            << "elapsedRealtimeNano() advanced too little after nanosleep()";
67    EXPECT_LT(endRealtimeNs - startRealtimeNs, SLEEP_NS + SLACK_NS)
68            << "elapsedRealtimeNano() advanced too much after nanosleep()";
69
70    EXPECT_GE(endRealtimeNs, endRealtimeMs * MS_IN_NS)
71            << "elapsedRealtime() and elapsedRealtimeNano() are inconsistent after nanosleep()";
72    EXPECT_LT(endRealtimeNs, (endRealtimeMs + SLACK_MS) * MS_IN_NS)
73            << "elapsedRealtime() and elapsedRealtimeNano() are inconsistent after nanosleep()";
74}
75