Alex Vakulenko | 177ddcc | 2015-04-29 15:06:51 -0700 | [diff] [blame] | 1 | // Copyright 2015 The Chromium OS Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
Alex Vakulenko | 9ed0cab | 2015-10-12 15:21:28 -0700 | [diff] [blame] | 5 | #include <brillo/backoff_entry.h> |
Alex Vakulenko | 177ddcc | 2015-04-29 15:06:51 -0700 | [diff] [blame] | 6 | #include <gtest/gtest.h> |
| 7 | |
| 8 | using base::TimeDelta; |
| 9 | using base::TimeTicks; |
| 10 | |
Alex Vakulenko | 9ed0cab | 2015-10-12 15:21:28 -0700 | [diff] [blame] | 11 | namespace brillo { |
Alex Vakulenko | 177ddcc | 2015-04-29 15:06:51 -0700 | [diff] [blame] | 12 | |
| 13 | BackoffEntry::Policy base_policy = { 0, 1000, 2.0, 0.0, 20000, 2000, false }; |
| 14 | |
| 15 | class TestBackoffEntry : public BackoffEntry { |
| 16 | public: |
| 17 | explicit TestBackoffEntry(const Policy* const policy) |
| 18 | : BackoffEntry(policy), |
| 19 | now_(TimeTicks()) { |
| 20 | // Work around initialization in constructor not picking up |
| 21 | // fake time. |
| 22 | SetCustomReleaseTime(TimeTicks()); |
| 23 | } |
| 24 | |
| 25 | ~TestBackoffEntry() override {} |
| 26 | |
| 27 | TimeTicks ImplGetTimeNow() const override { return now_; } |
| 28 | |
| 29 | void set_now(const TimeTicks& now) { |
| 30 | now_ = now; |
| 31 | } |
| 32 | |
| 33 | private: |
| 34 | TimeTicks now_; |
| 35 | |
| 36 | DISALLOW_COPY_AND_ASSIGN(TestBackoffEntry); |
| 37 | }; |
| 38 | |
| 39 | TEST(BackoffEntryTest, BaseTest) { |
| 40 | TestBackoffEntry entry(&base_policy); |
| 41 | EXPECT_FALSE(entry.ShouldRejectRequest()); |
| 42 | EXPECT_EQ(TimeDelta(), entry.GetTimeUntilRelease()); |
| 43 | |
| 44 | entry.InformOfRequest(false); |
| 45 | EXPECT_TRUE(entry.ShouldRejectRequest()); |
| 46 | EXPECT_EQ(TimeDelta::FromMilliseconds(1000), entry.GetTimeUntilRelease()); |
| 47 | } |
| 48 | |
| 49 | TEST(BackoffEntryTest, CanDiscardNeverExpires) { |
| 50 | BackoffEntry::Policy never_expires_policy = base_policy; |
| 51 | never_expires_policy.entry_lifetime_ms = -1; |
| 52 | TestBackoffEntry never_expires(&never_expires_policy); |
| 53 | EXPECT_FALSE(never_expires.CanDiscard()); |
| 54 | never_expires.set_now(TimeTicks() + TimeDelta::FromDays(100)); |
| 55 | EXPECT_FALSE(never_expires.CanDiscard()); |
| 56 | } |
| 57 | |
| 58 | TEST(BackoffEntryTest, CanDiscard) { |
| 59 | TestBackoffEntry entry(&base_policy); |
| 60 | // Because lifetime is non-zero, we shouldn't be able to discard yet. |
| 61 | EXPECT_FALSE(entry.CanDiscard()); |
| 62 | |
| 63 | // Test the "being used" case. |
| 64 | entry.InformOfRequest(false); |
| 65 | EXPECT_FALSE(entry.CanDiscard()); |
| 66 | |
| 67 | // Test the case where there are errors but we can time out. |
| 68 | entry.set_now( |
| 69 | entry.GetReleaseTime() + TimeDelta::FromMilliseconds(1)); |
| 70 | EXPECT_FALSE(entry.CanDiscard()); |
| 71 | entry.set_now(entry.GetReleaseTime() + TimeDelta::FromMilliseconds( |
| 72 | base_policy.maximum_backoff_ms + 1)); |
| 73 | EXPECT_TRUE(entry.CanDiscard()); |
| 74 | |
| 75 | // Test the final case (no errors, dependent only on specified lifetime). |
| 76 | entry.set_now(entry.GetReleaseTime() + TimeDelta::FromMilliseconds( |
| 77 | base_policy.entry_lifetime_ms - 1)); |
| 78 | entry.InformOfRequest(true); |
| 79 | EXPECT_FALSE(entry.CanDiscard()); |
| 80 | entry.set_now(entry.GetReleaseTime() + TimeDelta::FromMilliseconds( |
| 81 | base_policy.entry_lifetime_ms)); |
| 82 | EXPECT_TRUE(entry.CanDiscard()); |
| 83 | } |
| 84 | |
| 85 | TEST(BackoffEntryTest, CanDiscardAlwaysDelay) { |
| 86 | BackoffEntry::Policy always_delay_policy = base_policy; |
| 87 | always_delay_policy.always_use_initial_delay = true; |
| 88 | always_delay_policy.entry_lifetime_ms = 0; |
| 89 | |
| 90 | TestBackoffEntry entry(&always_delay_policy); |
| 91 | |
| 92 | // Because lifetime is non-zero, we shouldn't be able to discard yet. |
| 93 | entry.set_now(entry.GetReleaseTime() + TimeDelta::FromMilliseconds(2000)); |
| 94 | EXPECT_TRUE(entry.CanDiscard()); |
| 95 | |
| 96 | // Even with no failures, we wait until the delay before we allow discard. |
| 97 | entry.InformOfRequest(true); |
| 98 | EXPECT_FALSE(entry.CanDiscard()); |
| 99 | |
| 100 | // Wait until the delay expires, and we can discard the entry again. |
| 101 | entry.set_now(entry.GetReleaseTime() + TimeDelta::FromMilliseconds(1000)); |
| 102 | EXPECT_TRUE(entry.CanDiscard()); |
| 103 | } |
| 104 | |
| 105 | TEST(BackoffEntryTest, CanDiscardNotStored) { |
| 106 | BackoffEntry::Policy no_store_policy = base_policy; |
| 107 | no_store_policy.entry_lifetime_ms = 0; |
| 108 | TestBackoffEntry not_stored(&no_store_policy); |
| 109 | EXPECT_TRUE(not_stored.CanDiscard()); |
| 110 | } |
| 111 | |
| 112 | TEST(BackoffEntryTest, ShouldIgnoreFirstTwo) { |
| 113 | BackoffEntry::Policy lenient_policy = base_policy; |
| 114 | lenient_policy.num_errors_to_ignore = 2; |
| 115 | |
| 116 | BackoffEntry entry(&lenient_policy); |
| 117 | |
| 118 | entry.InformOfRequest(false); |
| 119 | EXPECT_FALSE(entry.ShouldRejectRequest()); |
| 120 | |
| 121 | entry.InformOfRequest(false); |
| 122 | EXPECT_FALSE(entry.ShouldRejectRequest()); |
| 123 | |
| 124 | entry.InformOfRequest(false); |
| 125 | EXPECT_TRUE(entry.ShouldRejectRequest()); |
| 126 | } |
| 127 | |
| 128 | TEST(BackoffEntryTest, ReleaseTimeCalculation) { |
| 129 | TestBackoffEntry entry(&base_policy); |
| 130 | |
| 131 | // With zero errors, should return "now". |
| 132 | TimeTicks result = entry.GetReleaseTime(); |
| 133 | EXPECT_EQ(entry.ImplGetTimeNow(), result); |
| 134 | |
| 135 | // 1 error. |
| 136 | entry.InformOfRequest(false); |
| 137 | result = entry.GetReleaseTime(); |
| 138 | EXPECT_EQ(entry.ImplGetTimeNow() + TimeDelta::FromMilliseconds(1000), result); |
| 139 | EXPECT_EQ(TimeDelta::FromMilliseconds(1000), entry.GetTimeUntilRelease()); |
| 140 | |
| 141 | // 2 errors. |
| 142 | entry.InformOfRequest(false); |
| 143 | result = entry.GetReleaseTime(); |
| 144 | EXPECT_EQ(entry.ImplGetTimeNow() + TimeDelta::FromMilliseconds(2000), result); |
| 145 | EXPECT_EQ(TimeDelta::FromMilliseconds(2000), entry.GetTimeUntilRelease()); |
| 146 | |
| 147 | // 3 errors. |
| 148 | entry.InformOfRequest(false); |
| 149 | result = entry.GetReleaseTime(); |
| 150 | EXPECT_EQ(entry.ImplGetTimeNow() + TimeDelta::FromMilliseconds(4000), result); |
| 151 | EXPECT_EQ(TimeDelta::FromMilliseconds(4000), entry.GetTimeUntilRelease()); |
| 152 | |
| 153 | // 6 errors (to check it doesn't pass maximum). |
| 154 | entry.InformOfRequest(false); |
| 155 | entry.InformOfRequest(false); |
| 156 | entry.InformOfRequest(false); |
| 157 | result = entry.GetReleaseTime(); |
| 158 | EXPECT_EQ( |
| 159 | entry.ImplGetTimeNow() + TimeDelta::FromMilliseconds(20000), result); |
| 160 | } |
| 161 | |
| 162 | TEST(BackoffEntryTest, ReleaseTimeCalculationAlwaysDelay) { |
| 163 | BackoffEntry::Policy always_delay_policy = base_policy; |
| 164 | always_delay_policy.always_use_initial_delay = true; |
| 165 | always_delay_policy.num_errors_to_ignore = 2; |
| 166 | |
| 167 | TestBackoffEntry entry(&always_delay_policy); |
| 168 | |
| 169 | // With previous requests, should return "now". |
| 170 | TimeTicks result = entry.GetReleaseTime(); |
| 171 | EXPECT_EQ(TimeDelta(), entry.GetTimeUntilRelease()); |
| 172 | |
| 173 | // 1 error. |
| 174 | entry.InformOfRequest(false); |
| 175 | EXPECT_EQ(TimeDelta::FromMilliseconds(1000), entry.GetTimeUntilRelease()); |
| 176 | |
| 177 | // 2 errors. |
| 178 | entry.InformOfRequest(false); |
| 179 | EXPECT_EQ(TimeDelta::FromMilliseconds(1000), entry.GetTimeUntilRelease()); |
| 180 | |
| 181 | // 3 errors, exponential backoff starts. |
| 182 | entry.InformOfRequest(false); |
| 183 | EXPECT_EQ(TimeDelta::FromMilliseconds(2000), entry.GetTimeUntilRelease()); |
| 184 | |
| 185 | // 4 errors. |
| 186 | entry.InformOfRequest(false); |
| 187 | EXPECT_EQ(TimeDelta::FromMilliseconds(4000), entry.GetTimeUntilRelease()); |
| 188 | |
| 189 | // 8 errors (to check it doesn't pass maximum). |
| 190 | entry.InformOfRequest(false); |
| 191 | entry.InformOfRequest(false); |
| 192 | entry.InformOfRequest(false); |
| 193 | entry.InformOfRequest(false); |
| 194 | result = entry.GetReleaseTime(); |
| 195 | EXPECT_EQ(TimeDelta::FromMilliseconds(20000), entry.GetTimeUntilRelease()); |
| 196 | } |
| 197 | |
| 198 | TEST(BackoffEntryTest, ReleaseTimeCalculationWithJitter) { |
| 199 | for (int i = 0; i < 10; ++i) { |
| 200 | BackoffEntry::Policy jittery_policy = base_policy; |
| 201 | jittery_policy.jitter_factor = 0.2; |
| 202 | |
| 203 | TestBackoffEntry entry(&jittery_policy); |
| 204 | |
| 205 | entry.InformOfRequest(false); |
| 206 | entry.InformOfRequest(false); |
| 207 | entry.InformOfRequest(false); |
| 208 | TimeTicks result = entry.GetReleaseTime(); |
| 209 | EXPECT_LE( |
| 210 | entry.ImplGetTimeNow() + TimeDelta::FromMilliseconds(3200), result); |
| 211 | EXPECT_GE( |
| 212 | entry.ImplGetTimeNow() + TimeDelta::FromMilliseconds(4000), result); |
| 213 | } |
| 214 | } |
| 215 | |
| 216 | TEST(BackoffEntryTest, FailureThenSuccess) { |
| 217 | TestBackoffEntry entry(&base_policy); |
| 218 | |
| 219 | // Failure count 1, establishes horizon. |
| 220 | entry.InformOfRequest(false); |
| 221 | TimeTicks release_time = entry.GetReleaseTime(); |
| 222 | EXPECT_EQ(TimeTicks() + TimeDelta::FromMilliseconds(1000), release_time); |
| 223 | |
| 224 | // Success, failure count 0, should not advance past |
| 225 | // the horizon that was already set. |
| 226 | entry.set_now(release_time - TimeDelta::FromMilliseconds(200)); |
| 227 | entry.InformOfRequest(true); |
| 228 | EXPECT_EQ(release_time, entry.GetReleaseTime()); |
| 229 | |
| 230 | // Failure, failure count 1. |
| 231 | entry.InformOfRequest(false); |
| 232 | EXPECT_EQ(release_time + TimeDelta::FromMilliseconds(800), |
| 233 | entry.GetReleaseTime()); |
| 234 | } |
| 235 | |
| 236 | TEST(BackoffEntryTest, FailureThenSuccessAlwaysDelay) { |
| 237 | BackoffEntry::Policy always_delay_policy = base_policy; |
| 238 | always_delay_policy.always_use_initial_delay = true; |
| 239 | always_delay_policy.num_errors_to_ignore = 1; |
| 240 | |
| 241 | TestBackoffEntry entry(&always_delay_policy); |
| 242 | |
| 243 | // Failure count 1. |
| 244 | entry.InformOfRequest(false); |
| 245 | EXPECT_EQ(TimeDelta::FromMilliseconds(1000), entry.GetTimeUntilRelease()); |
| 246 | |
| 247 | // Failure count 2. |
| 248 | entry.InformOfRequest(false); |
| 249 | EXPECT_EQ(TimeDelta::FromMilliseconds(2000), entry.GetTimeUntilRelease()); |
| 250 | entry.set_now(entry.GetReleaseTime() + TimeDelta::FromMilliseconds(2000)); |
| 251 | |
| 252 | // Success. We should go back to the original delay. |
| 253 | entry.InformOfRequest(true); |
| 254 | EXPECT_EQ(TimeDelta::FromMilliseconds(1000), entry.GetTimeUntilRelease()); |
| 255 | |
| 256 | // Failure count reaches 2 again. We should increase the delay once more. |
| 257 | entry.InformOfRequest(false); |
| 258 | EXPECT_EQ(TimeDelta::FromMilliseconds(2000), entry.GetTimeUntilRelease()); |
| 259 | entry.set_now(entry.GetReleaseTime() + TimeDelta::FromMilliseconds(2000)); |
| 260 | } |
| 261 | |
| 262 | TEST(BackoffEntryTest, RetainCustomHorizon) { |
| 263 | TestBackoffEntry custom(&base_policy); |
| 264 | TimeTicks custom_horizon = TimeTicks() + TimeDelta::FromDays(3); |
| 265 | custom.SetCustomReleaseTime(custom_horizon); |
| 266 | custom.InformOfRequest(false); |
| 267 | custom.InformOfRequest(true); |
| 268 | custom.set_now(TimeTicks() + TimeDelta::FromDays(2)); |
| 269 | custom.InformOfRequest(false); |
| 270 | custom.InformOfRequest(true); |
| 271 | EXPECT_EQ(custom_horizon, custom.GetReleaseTime()); |
| 272 | |
| 273 | // Now check that once we are at or past the custom horizon, |
| 274 | // we get normal behavior. |
| 275 | custom.set_now(TimeTicks() + TimeDelta::FromDays(3)); |
| 276 | custom.InformOfRequest(false); |
| 277 | EXPECT_EQ( |
| 278 | TimeTicks() + TimeDelta::FromDays(3) + TimeDelta::FromMilliseconds(1000), |
| 279 | custom.GetReleaseTime()); |
| 280 | } |
| 281 | |
| 282 | TEST(BackoffEntryTest, RetainCustomHorizonWhenInitialErrorsIgnored) { |
| 283 | // Regression test for a bug discovered during code review. |
| 284 | BackoffEntry::Policy lenient_policy = base_policy; |
| 285 | lenient_policy.num_errors_to_ignore = 1; |
| 286 | TestBackoffEntry custom(&lenient_policy); |
| 287 | TimeTicks custom_horizon = TimeTicks() + TimeDelta::FromDays(3); |
| 288 | custom.SetCustomReleaseTime(custom_horizon); |
| 289 | custom.InformOfRequest(false); // This must not reset the horizon. |
| 290 | EXPECT_EQ(custom_horizon, custom.GetReleaseTime()); |
| 291 | } |
| 292 | |
| 293 | TEST(BackoffEntryTest, OverflowProtection) { |
| 294 | BackoffEntry::Policy large_multiply_policy = base_policy; |
| 295 | large_multiply_policy.multiply_factor = 256; |
| 296 | TestBackoffEntry custom(&large_multiply_policy); |
| 297 | |
| 298 | // Trigger enough failures such that more than 11 bits of exponent are used |
| 299 | // to represent the exponential backoff intermediate values. Given a multiply |
| 300 | // factor of 256 (2^8), 129 iterations is enough: 2^(8*(129-1)) = 2^1024. |
| 301 | for (int i = 0; i < 129; ++i) { |
Alex Vakulenko | 9ed0cab | 2015-10-12 15:21:28 -0700 | [diff] [blame] | 302 | custom.set_now(custom.ImplGetTimeNow() + custom.GetTimeUntilRelease()); |
| 303 | custom.InformOfRequest(false); |
| 304 | ASSERT_TRUE(custom.ShouldRejectRequest()); |
Alex Vakulenko | 177ddcc | 2015-04-29 15:06:51 -0700 | [diff] [blame] | 305 | } |
| 306 | |
| 307 | // Max delay should still be respected. |
| 308 | EXPECT_EQ(20000, custom.GetTimeUntilRelease().InMilliseconds()); |
| 309 | } |
| 310 | |
| 311 | } // namespace |