Anton Spaans | ed17bc1 | 2018-03-20 18:28:53 -0400 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2016-2018 JetBrains s.r.o. |
| 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 | package kotlinx.coroutines.experimental.test |
| 18 | |
| 19 | import kotlinx.coroutines.experimental.* |
| 20 | import kotlinx.coroutines.experimental.internal.* |
| 21 | import java.util.concurrent.TimeUnit |
| 22 | import kotlin.coroutines.experimental.* |
| 23 | |
| 24 | /** |
| 25 | * This [CoroutineContext] dispatcher can be used to simulate virtual time to speed up |
| 26 | * code, especially tests, that deal with delays and timeouts in Coroutines. |
| 27 | * |
| 28 | * Provide an instance of this TestCoroutineContext when calling the *non-blocking* [launch] or [async] |
| 29 | * and then advance time or trigger the actions to make the co-routines execute as soon as possible. |
| 30 | * |
| 31 | * This works much like the *TestScheduler* in RxJava2, which allows to speed up tests that deal |
| 32 | * with non-blocking Rx chains that contain delays, timeouts, intervals and such. |
| 33 | * |
| 34 | * This dispatcher can also handle *blocking* coroutines that are started by [runBlocking]. |
| 35 | * This dispatcher's virtual time will be automatically advanced based based on the delayed actions |
| 36 | * within the Coroutine(s). |
| 37 | * |
| 38 | * @param name A user-readable name for debugging purposes. |
| 39 | */ |
| 40 | class TestCoroutineContext(private val name: String? = null) : CoroutineContext { |
| 41 | private val uncaughtExceptions = mutableListOf<Throwable>() |
| 42 | |
| 43 | private val ctxDispatcher = Dispatcher() |
| 44 | |
| 45 | private val ctxHandler = CoroutineExceptionHandler { _, exception -> |
| 46 | uncaughtExceptions += exception |
| 47 | } |
| 48 | |
| 49 | // The ordered queue for the runnable tasks. |
| 50 | private val queue = ThreadSafeHeap<TimedRunnable>() |
| 51 | |
| 52 | // The per-scheduler global order counter. |
| 53 | private var counter = 0L |
| 54 | |
| 55 | // Storing time in nanoseconds internally. |
| 56 | private var time = 0L |
| 57 | |
| 58 | /** |
| 59 | * Exceptions that were caught during a [launch] or a [async] + [Deferred.await]. |
| 60 | */ |
| 61 | public val exceptions: List<Throwable> get() = uncaughtExceptions |
| 62 | |
| 63 | // -- CoroutineContext implementation |
| 64 | |
| 65 | public override fun <R> fold(initial: R, operation: (R, CoroutineContext.Element) -> R): R = |
| 66 | operation(operation(initial, ctxDispatcher), ctxHandler) |
| 67 | |
| 68 | @Suppress("UNCHECKED_CAST") |
| 69 | public override fun <E : CoroutineContext.Element> get(key: CoroutineContext.Key<E>): E? = when { |
| 70 | key === ContinuationInterceptor -> ctxDispatcher as E |
| 71 | key === CoroutineExceptionHandler -> ctxHandler as E |
| 72 | else -> null |
| 73 | } |
| 74 | |
| 75 | public override fun minusKey(key: CoroutineContext.Key<*>): CoroutineContext = when { |
| 76 | key === ContinuationInterceptor -> ctxHandler |
| 77 | key === CoroutineExceptionHandler -> ctxDispatcher |
| 78 | else -> this |
| 79 | } |
| 80 | |
| 81 | /** |
| 82 | * Returns the current virtual clock-time as it is known to this CoroutineContext. |
| 83 | * |
| 84 | * @param unit The [TimeUnit] in which the clock-time must be returned. |
| 85 | * @return The virtual clock-time |
| 86 | */ |
| 87 | public fun now(unit: TimeUnit = TimeUnit.MILLISECONDS)= |
| 88 | unit.convert(time, TimeUnit.NANOSECONDS) |
| 89 | |
| 90 | /** |
| 91 | * Moves the CoroutineContext's virtual clock forward by a specified amount of time. |
| 92 | * |
| 93 | * The returned delay-time can be larger than the specified delay-time if the code |
| 94 | * under test contains *blocking* Coroutines. |
| 95 | * |
| 96 | * @param delayTime The amount of time to move the CoroutineContext's clock forward. |
| 97 | * @param unit The [TimeUnit] in which [delayTime] and the return value is expressed. |
| 98 | * @return The amount of delay-time that this CoroutinesContext's clock has been forwarded. |
| 99 | */ |
| 100 | public fun advanceTimeBy(delayTime: Long, unit: TimeUnit = TimeUnit.MILLISECONDS): Long { |
| 101 | val oldTime = time |
| 102 | advanceTimeTo(oldTime + unit.toNanos(delayTime), TimeUnit.NANOSECONDS) |
| 103 | return unit.convert(time - oldTime, TimeUnit.NANOSECONDS) |
| 104 | } |
| 105 | |
| 106 | /** |
| 107 | * Moves the CoroutineContext's clock-time to a particular moment in time. |
| 108 | * |
| 109 | * @param targetTime The point in time to which to move the CoroutineContext's clock. |
| 110 | * @param unit The [TimeUnit] in which [targetTime] is expressed. |
| 111 | */ |
| 112 | fun advanceTimeTo(targetTime: Long, unit: TimeUnit = TimeUnit.MILLISECONDS) { |
| 113 | val nanoTime = unit.toNanos(targetTime) |
| 114 | triggerActions(nanoTime) |
| 115 | if (nanoTime > time) time = nanoTime |
| 116 | } |
| 117 | |
| 118 | /** |
| 119 | * Triggers any actions that have not yet been triggered and that are scheduled to be triggered at or |
| 120 | * before this CoroutineContext's present virtual clock-time. |
| 121 | */ |
| 122 | public fun triggerActions() = triggerActions(time) |
| 123 | |
| 124 | /** |
| 125 | * Cancels all not yet triggered actions. Be careful calling this, since it can seriously |
| 126 | * mess with your coroutines work. This method should usually be called on tear-down of a |
| 127 | * unit test. |
| 128 | */ |
| 129 | public fun cancelAllActions() { |
| 130 | // An 'is-empty' test is required to avoid a NullPointerException in the 'clear()' method |
| 131 | if (!queue.isEmpty) queue.clear() |
| 132 | } |
| 133 | |
| 134 | /** |
| 135 | * This method does nothing if there is one unhandled exception that satisfies the given predicate. |
| 136 | * Otherwise it throws an [AssertionError] with the given message. |
| 137 | * |
| 138 | * (this method will clear the list of unhandled exceptions) |
| 139 | * |
| 140 | * @param message Message of the [AssertionError]. Defaults to an empty String. |
| 141 | * @param predicate The predicate that must be satisfied. |
| 142 | */ |
| 143 | public fun assertUnhandledException(message: String = "", predicate: (Throwable) -> Boolean) { |
| 144 | if (uncaughtExceptions.size != 1 || !predicate(uncaughtExceptions[0])) throw AssertionError(message) |
| 145 | uncaughtExceptions.clear() |
| 146 | } |
| 147 | |
| 148 | /** |
| 149 | * This method does nothing if there are no unhandled exceptions or all of them satisfy the given predicate. |
| 150 | * Otherwise it throws an [AssertionError] with the given message. |
| 151 | * |
| 152 | * (this method will clear the list of unhandled exceptions) |
| 153 | * |
| 154 | * @param message Message of the [AssertionError]. Defaults to an empty String. |
| 155 | * @param predicate The predicate that must be satisfied. |
| 156 | */ |
| 157 | public fun assertAllUnhandledExceptions(message: String = "", predicate: (Throwable) -> Boolean) { |
| 158 | if (!uncaughtExceptions.all(predicate)) throw AssertionError(message) |
| 159 | uncaughtExceptions.clear() |
| 160 | } |
| 161 | |
| 162 | /** |
| 163 | * This method does nothing if one or more unhandled exceptions satisfy the given predicate. |
| 164 | * Otherwise it throws an [AssertionError] with the given message. |
| 165 | * |
| 166 | * (this method will clear the list of unhandled exceptions) |
| 167 | * |
| 168 | * @param message Message of the [AssertionError]. Defaults to an empty String. |
| 169 | * @param predicate The predicate that must be satisfied. |
| 170 | */ |
| 171 | public fun assertAnyUnhandledException(message: String = "", predicate: (Throwable) -> Boolean) { |
| 172 | if (!uncaughtExceptions.any(predicate)) throw AssertionError(message) |
| 173 | uncaughtExceptions.clear() |
| 174 | } |
| 175 | |
| 176 | /** |
| 177 | * This method does nothing if the list of unhandled exceptions satisfy the given predicate. |
| 178 | * Otherwise it throws an [AssertionError] with the given message. |
| 179 | * |
| 180 | * (this method will clear the list of unhandled exceptions) |
| 181 | * |
| 182 | * @param message Message of the [AssertionError]. Defaults to an empty String. |
| 183 | * @param predicate The predicate that must be satisfied. |
| 184 | */ |
| 185 | public fun assertExceptions(message: String = "", predicate: (List<Throwable>) -> Boolean) { |
| 186 | if (!predicate(uncaughtExceptions)) throw AssertionError(message) |
| 187 | uncaughtExceptions.clear() |
| 188 | } |
| 189 | |
| 190 | private fun post(block: Runnable) = |
| 191 | queue.addLast(TimedRunnable(block, counter++)) |
| 192 | |
| 193 | private fun postDelayed(block: Runnable, delayTime: Long) = |
| 194 | TimedRunnable(block, counter++, time + TimeUnit.MILLISECONDS.toNanos(delayTime)) |
| 195 | .also { |
| 196 | queue.addLast(it) |
| 197 | } |
| 198 | |
| 199 | private fun processNextEvent(): Long { |
| 200 | val current = queue.peek() |
| 201 | if (current != null) { |
| 202 | /** Automatically advance time for [EventLoop]-callbacks */ |
| 203 | triggerActions(current.time) |
| 204 | } |
| 205 | return if (queue.isEmpty) Long.MAX_VALUE else 0L |
| 206 | } |
| 207 | |
| 208 | private fun triggerActions(targetTime: Long) { |
| 209 | while (true) { |
| 210 | val current = queue.removeFirstIf { it.time <= targetTime } ?: break |
| 211 | // If the scheduled time is 0 (immediate) use current virtual time |
| 212 | if (current.time != 0L) time = current.time |
| 213 | current.run() |
| 214 | } |
| 215 | } |
| 216 | |
| 217 | public override fun toString(): String = name ?: "TestCoroutineContext@$hexAddress" |
| 218 | |
| 219 | private inner class Dispatcher : CoroutineDispatcher(), Delay, EventLoop { |
| 220 | override fun dispatch(context: CoroutineContext, block: Runnable) = post(block) |
| 221 | |
| 222 | override fun scheduleResumeAfterDelay(time: Long, unit: TimeUnit, continuation: CancellableContinuation<Unit>) { |
| 223 | postDelayed(Runnable { |
| 224 | with(continuation) { resumeUndispatched(Unit) } |
| 225 | }, unit.toMillis(time)) |
| 226 | } |
| 227 | |
| 228 | override fun invokeOnTimeout(time: Long, unit: TimeUnit, block: Runnable): DisposableHandle { |
| 229 | val node = postDelayed(block, unit.toMillis(time)) |
| 230 | return object : DisposableHandle { |
| 231 | override fun dispose() { |
| 232 | queue.remove(node) |
| 233 | } |
| 234 | } |
| 235 | } |
| 236 | |
| 237 | override fun processNextEvent() = this@TestCoroutineContext.processNextEvent() |
| 238 | |
| 239 | public override fun toString(): String = "Dispatcher(${this@TestCoroutineContext})" |
| 240 | } |
| 241 | } |
| 242 | |
| 243 | private class TimedRunnable( |
| 244 | private val run: Runnable, |
| 245 | private val count: Long = 0, |
| 246 | @JvmField internal val time: Long = 0 |
| 247 | ) : Comparable<TimedRunnable>, Runnable by run, ThreadSafeHeapNode { |
| 248 | override var index: Int = 0 |
| 249 | |
| 250 | override fun run() = run.run() |
| 251 | |
| 252 | override fun compareTo(other: TimedRunnable) = if (time == other.time) { |
| 253 | count.compareTo(other.count) |
| 254 | } else { |
| 255 | time.compareTo(other.time) |
| 256 | } |
| 257 | |
| 258 | override fun toString() = "TimedRunnable(time=$time, run=$run)" |
| 259 | } |
| 260 | |
| 261 | /** |
| 262 | * Executes a block of code in which a unit-test can be written using the provided [TestCoroutineContext]. The provided |
| 263 | * [TestCoroutineContext] is available in the [testBody] as the `this` receiver. |
| 264 | * |
| 265 | * The [testBody] is executed and an [AssertionError] is thrown if the list of unhandled exceptions is not empty and |
| 266 | * contains any exception that is not a [CancellationException]. |
| 267 | * |
| 268 | * If the [testBody] successfully executes one of the [TestCoroutineContext.assertAllUnhandledExceptions], |
| 269 | * [TestCoroutineContext.assertAnyUnhandledException], [TestCoroutineContext.assertUnhandledException] or |
| 270 | * [TestCoroutineContext.assertExceptions], the list of unhandled exceptions will have been cleared and this method will |
| 271 | * not throw an [AssertionError]. |
| 272 | * |
| 273 | * @param testContext The provided [TestCoroutineContext]. If not specified, a default [TestCoroutineContext] will be |
| 274 | * provided instead. |
| 275 | * @param testBody The code of the unit-test. |
| 276 | */ |
| 277 | public fun withTestContext(testContext: TestCoroutineContext = TestCoroutineContext(), testBody: TestCoroutineContext.() -> Unit) { |
| 278 | with (testContext) { |
| 279 | testBody() |
| 280 | |
| 281 | if (!exceptions.all { it is CancellationException }) { |
| 282 | throw AssertionError("Coroutine encountered unhandled exceptions:\n${exceptions}") |
| 283 | } |
| 284 | } |
| 285 | } |