1 /*
2  * Copyright (C) 2017 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 "android-base/chrono_utils.h"
18 
19 #include <time.h>
20 
21 #include <chrono>
22 #include <sstream>
23 #include <string>
24 #include <thread>
25 
26 #include <gtest/gtest.h>
27 
28 namespace android {
29 namespace base {
30 
GetBootTimeSeconds()31 std::chrono::seconds GetBootTimeSeconds() {
32   struct timespec now;
33   clock_gettime(CLOCK_BOOTTIME, &now);
34 
35   auto now_tp = boot_clock::time_point(std::chrono::seconds(now.tv_sec) +
36                                        std::chrono::nanoseconds(now.tv_nsec));
37   return std::chrono::duration_cast<std::chrono::seconds>(now_tp.time_since_epoch());
38 }
39 
40 // Tests (at least) the seconds accuracy of the boot_clock::now() method.
TEST(ChronoUtilsTest,BootClockNowSeconds)41 TEST(ChronoUtilsTest, BootClockNowSeconds) {
42   auto now = GetBootTimeSeconds();
43   auto boot_seconds =
44       std::chrono::duration_cast<std::chrono::seconds>(boot_clock::now().time_since_epoch());
45   EXPECT_EQ(now, boot_seconds);
46 }
47 
48 template <typename T>
ExpectAboutEqual(T expected,T actual)49 void ExpectAboutEqual(T expected, T actual) {
50   auto expected_upper_bound = expected * 1.05f;
51   auto expected_lower_bound = expected * .95;
52   EXPECT_GT(expected_upper_bound, actual);
53   EXPECT_LT(expected_lower_bound, actual);
54 }
55 
TEST(ChronoUtilsTest,TimerDurationIsSane)56 TEST(ChronoUtilsTest, TimerDurationIsSane) {
57   auto start = boot_clock::now();
58   Timer t;
59   std::this_thread::sleep_for(50ms);
60   auto stop = boot_clock::now();
61   auto stop_timer = t.duration();
62 
63   auto expected = std::chrono::duration_cast<std::chrono::milliseconds>(stop - start);
64   ExpectAboutEqual(expected, stop_timer);
65 }
66 
TEST(ChronoUtilsTest,TimerOstream)67 TEST(ChronoUtilsTest, TimerOstream) {
68   Timer t;
69   std::this_thread::sleep_for(50ms);
70   auto stop_timer = t.duration().count();
71   std::stringstream os;
72   os << t;
73   decltype(stop_timer) stop_timer_from_stream;
74   os >> stop_timer_from_stream;
75   EXPECT_NE(0, stop_timer);
76   ExpectAboutEqual(stop_timer, stop_timer_from_stream);
77 }
78 
79 }  // namespace base
80 }  // namespace android
81