1 // Copyright 2019 The Chromium Authors
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "base/timer/lap_timer.h"
6
7 #include "base/test/task_environment.h"
8 #include "base/time/time.h"
9 #include "build/build_config.h"
10 #include "testing/gtest/include/gtest/gtest.h"
11
12 // This file contains a minimal unit test for LapTimer, used for benchmarking.
13 // This file is supposed to match closely with the example code, documented in
14 // lap_timer.h. Please update that documentation if you need to change things.
15
16 namespace base {
17
18 namespace test {
19
20 namespace {
21
22 constexpr base::TimeDelta kTimeLimit = base::Milliseconds(15);
23 constexpr base::TimeDelta kTimeAdvance = base::Milliseconds(1);
24 constexpr int kWarmupRuns = 5;
25 constexpr int kTimeCheckInterval = 10;
26
27 } // namespace
28
TEST(LapTimer,UsageExample)29 TEST(LapTimer, UsageExample) {
30 TaskEnvironment task_environment(TaskEnvironment::TimeSource::MOCK_TIME);
31
32 LapTimer timer(kWarmupRuns, kTimeLimit, kTimeCheckInterval);
33
34 EXPECT_FALSE(timer.HasTimeLimitExpired());
35 EXPECT_FALSE(timer.IsWarmedUp());
36
37 do {
38 task_environment.FastForwardBy(kTimeAdvance);
39 timer.NextLap();
40 } while (!timer.HasTimeLimitExpired());
41
42 EXPECT_NEAR(timer.LapsPerSecond(), 1000, 0.1);
43 EXPECT_NEAR(timer.TimePerLap().InMillisecondsF(), 1.0f, 0.1);
44 // Output number of laps is 20, because the warm up runs are ignored and the
45 // timer is only checked every kTimeInterval laps.
46 EXPECT_EQ(timer.NumLaps(), 20);
47
48 EXPECT_TRUE(timer.HasTimeLimitExpired());
49 EXPECT_TRUE(timer.IsWarmedUp());
50 }
51
52 #if !BUILDFLAG(IS_IOS)
53 // iOS simulator does not support using ThreadTicks.
TEST(LapTimer,ThreadTicksUsageExample)54 TEST(LapTimer, ThreadTicksUsageExample) {
55 TaskEnvironment task_environment(TaskEnvironment::TimeSource::MOCK_TIME);
56 LapTimer timer(kWarmupRuns, kTimeLimit, kTimeCheckInterval,
57 LapTimer::TimerMethod::kUseThreadTicks);
58
59 EXPECT_FALSE(timer.HasTimeLimitExpired());
60 EXPECT_FALSE(timer.IsWarmedUp());
61
62 do {
63 task_environment.FastForwardBy(kTimeAdvance);
64 timer.NextLap();
65 } while (!timer.HasTimeLimitExpired());
66
67 // Because advancing the TaskEnvironment time won't affect the
68 // ThreadTicks, laps will be much faster than the regular UsageExample.
69 EXPECT_GT(timer.LapsPerSecond(), 1000);
70 EXPECT_LT(timer.TimePerLap().InMillisecondsF(), 1.0f);
71 EXPECT_GT(timer.NumLaps(), 20);
72
73 EXPECT_TRUE(timer.HasTimeLimitExpired());
74 EXPECT_TRUE(timer.IsWarmedUp());
75 }
76 #endif
77
78 } // namespace test
79 } // namespace base
80