swift-nio/Tests/NIOCoreTests/AsyncSequences/NIOThrowingAsyncSequenceTes...

797 lines
29 KiB
Swift

//===----------------------------------------------------------------------===//
//
// This source file is part of the SwiftNIO open source project
//
// Copyright (c) 2022 Apple Inc. and the SwiftNIO project authors
// Licensed under Apache License v2.0
//
// See LICENSE.txt for license information
// See CONTRIBUTORS.txt for the list of SwiftNIO project authors
//
// SPDX-License-Identifier: Apache-2.0
//
//===----------------------------------------------------------------------===//
import NIOCore
import XCTest
@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
final class NIOThrowingAsyncSequenceProducerTests: XCTestCase {
private var backPressureStrategy: MockNIOElementStreamBackPressureStrategy!
private var delegate: MockNIOBackPressuredStreamSourceDelegate!
private var sequence: NIOThrowingAsyncSequenceProducer<
Int,
Error,
MockNIOElementStreamBackPressureStrategy,
MockNIOBackPressuredStreamSourceDelegate
>!
private var source: NIOThrowingAsyncSequenceProducer<
Int,
Error,
MockNIOElementStreamBackPressureStrategy,
MockNIOBackPressuredStreamSourceDelegate
>.Source!
override func setUp() {
super.setUp()
self.backPressureStrategy = .init()
self.delegate = .init()
let result = NIOThrowingAsyncSequenceProducer.makeSequence(
elementType: Int.self,
failureType: Error.self,
backPressureStrategy: self.backPressureStrategy,
delegate: self.delegate
)
self.source = result.source
self.sequence = result.sequence
}
override func tearDown() {
self.backPressureStrategy = nil
self.delegate = nil
self.sequence = nil
super.tearDown()
}
// MARK: - End to end tests
func testBackPressure() async throws {
let lowWatermark = 2
let higherWatermark = 5
self.backPressureStrategy.didYieldHandler = { bufferDepth in
bufferDepth < higherWatermark
}
self.backPressureStrategy.didNextHandler = { bufferDepth in
bufferDepth < lowWatermark
}
let iterator = self.sequence.makeAsyncIterator()
XCTAssertEqual(self.source.yield(contentsOf: [1, 2, 3]), .produceMore)
XCTAssertEqual(self.source.yield(contentsOf: [4, 5, 6]), .stopProducing)
XCTAssertEqualWithoutAutoclosure(try await iterator.next(), 1)
XCTAssertEqualWithoutAutoclosure(try await iterator.next(), 2)
XCTAssertEqualWithoutAutoclosure(try await iterator.next(), 3)
XCTAssertEqualWithoutAutoclosure(try await iterator.next(), 4)
XCTAssertEqualWithoutAutoclosure(try await iterator.next(), 5)
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.produceMore])
XCTAssertEqual(self.source.yield(contentsOf: [7, 8, 9, 10, 11]), .stopProducing)
}
// MARK: - Yield
func testYield_whenInitial_andStopProducing() async {
self.backPressureStrategy.didYieldHandler = { _ in false }
let result = self.source.yield(contentsOf: [1])
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didYield])
XCTAssertEqual(result, .stopProducing)
}
func testYield_whenInitial_andProduceMore() async {
self.backPressureStrategy.didYieldHandler = { _ in true }
let result = self.source.yield(contentsOf: [1])
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didYield])
XCTAssertEqual(result, .produceMore)
}
func testYield_whenStreaming_andSuspended_andStopProducing() async throws {
self.backPressureStrategy.didYieldHandler = { _ in false }
// We are registering our demand and sleeping a bit to make
// sure the other child task runs when the demand is registered
let sequence = try XCTUnwrap(self.sequence)
let element: Int? = try await withThrowingTaskGroup(of: Int?.self) { group in
group.addTask {
try await sequence.first { _ in true }
}
try await Task.sleep(nanoseconds: 1_000_000)
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didNext])
let result = self.source.yield(contentsOf: [1])
XCTAssertEqual(result, .stopProducing)
return try await group.next() ?? nil
}
XCTAssertEqual(element, 1)
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didYield])
}
func testYield_whenStreaming_andSuspended_andProduceMore() async throws {
self.backPressureStrategy.didYieldHandler = { _ in true }
// We are registering our demand and sleeping a bit to make
// sure the other child task runs when the demand is registered
let sequence = try XCTUnwrap(self.sequence)
let element: Int? = try await withThrowingTaskGroup(of: Int?.self) { group in
group.addTask {
try await sequence.first { _ in true }
}
try await Task.sleep(nanoseconds: 1_000_000)
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didNext])
let result = self.source.yield(contentsOf: [1])
XCTAssertEqual(result, .produceMore)
return try await group.next() ?? nil
}
XCTAssertEqual(element, 1)
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didYield])
}
func testYieldEmptySequence_whenStreaming_andSuspended_andStopProducing() async throws {
self.backPressureStrategy.didYieldHandler = { _ in false }
// We are registering our demand and sleeping a bit to make
// sure the other child task runs when the demand is registered
let sequence = try XCTUnwrap(self.sequence)
try await withThrowingTaskGroup(of: Void.self) { group in
group.addTask {
_ = try await sequence.first { _ in true }
}
try await Task.sleep(nanoseconds: 1_000_000)
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didNext])
let result = self.source.yield(contentsOf: [])
XCTAssertEqual(result, .stopProducing)
group.cancelAll()
}
}
func testYieldEmptySequence_whenStreaming_andSuspended_andProduceMore() async throws {
self.backPressureStrategy.didYieldHandler = { _ in true }
// We are registering our demand and sleeping a bit to make
// sure the other child task runs when the demand is registered
let sequence = try XCTUnwrap(self.sequence)
try await withThrowingTaskGroup(of: Void.self) { group in
group.addTask {
_ = try await sequence.first { _ in true }
}
try await Task.sleep(nanoseconds: 1_000_000)
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didNext])
let result = self.source.yield(contentsOf: [])
XCTAssertEqual(result, .stopProducing)
group.cancelAll()
}
}
func testYield_whenStreaming_andNotSuspended_andStopProducing() async throws {
self.backPressureStrategy.didYieldHandler = { _ in false }
// This transitions the sequence into streaming
_ = self.source.yield(contentsOf: [])
let result = self.source.yield(contentsOf: [1])
XCTAssertEqual(result, .stopProducing)
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(2).collect(), [.didYield, .didYield])
}
func testYield_whenStreaming_andNotSuspended_andProduceMore() async throws {
self.backPressureStrategy.didYieldHandler = { _ in true }
// This transitions the sequence into streaming
_ = self.source.yield(contentsOf: [])
let result = self.source.yield(contentsOf: [1])
XCTAssertEqual(result, .produceMore)
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(2).collect(), [.didYield, .didYield])
}
func testYield_whenSourceFinished() async throws {
self.source.finish()
let result = self.source.yield(contentsOf: [1])
XCTAssertEqual(result, .dropped)
}
// MARK: - Finish
func testFinish_whenInitial() async {
self.source.finish()
}
func testFinish_whenStreaming_andSuspended() async throws {
// We are registering our demand and sleeping a bit to make
// sure the other child task runs when the demand is registered
let sequence = try XCTUnwrap(self.sequence)
let element: Int? = try await withThrowingTaskGroup(of: Int?.self) { group in
group.addTask {
let element = try await sequence.first { _ in true }
return element
}
try await Task.sleep(nanoseconds: 1_000_000)
self.source.finish()
return try await group.next() ?? nil
}
XCTAssertEqual(element, nil)
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
}
func testFinish_whenStreaming_andNotSuspended_andBufferEmpty() async throws {
_ = self.source.yield(contentsOf: [])
self.source.finish()
let sequence = try XCTUnwrap(self.sequence)
let element: Int? = try await withThrowingTaskGroup(of: Int?.self) { group in
group.addTask {
return try await sequence.first { _ in true }
}
return try await group.next() ?? nil
}
XCTAssertNil(element)
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
}
func testFinish_whenStreaming_andNotSuspended_andBufferNotEmpty() async throws {
_ = self.source.yield(contentsOf: [1])
self.source.finish()
let sequence = try XCTUnwrap(self.sequence)
let element: Int? = try await withThrowingTaskGroup(of: Int?.self) { group in
group.addTask {
return try await sequence.first { _ in true }
}
return try await group.next() ?? nil
}
XCTAssertEqual(element, 1)
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
}
func testFinish_whenFinished() async throws {
self.source.finish()
_ = try await self.sequence.first { _ in true }
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
self.source.finish()
}
// MARK: - Finish with Error
func testFinishError_whenInitial() async {
self.source.finish(ChannelError.alreadyClosed)
await XCTAssertThrowsError(try await self.sequence.first { _ in true }) { error in
XCTAssertEqual(error as? ChannelError, .alreadyClosed)
}
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
}
func testFinishError_whenStreaming_andSuspended() async throws {
// We are registering our demand and sleeping a bit to make
// sure the other child task runs when the demand is registered
let sequence = try XCTUnwrap(self.sequence)
await XCTAssertThrowsError(try await withThrowingTaskGroup(of: Void.self) { group in
group.addTask {
_ = try await sequence.first { _ in true }
}
try await Task.sleep(nanoseconds: 1_000_000)
self.source.finish(ChannelError.alreadyClosed)
try await group.next()
}) { error in
XCTAssertEqual(error as? ChannelError, .alreadyClosed)
}
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
}
func testFinishError_whenStreaming_andNotSuspended_andBufferEmpty() async throws {
_ = self.source.yield(contentsOf: [])
self.source.finish(ChannelError.alreadyClosed)
let sequence = try XCTUnwrap(self.sequence)
await XCTAssertThrowsError(try await withThrowingTaskGroup(of: Void.self) { group in
group.addTask {
_ = try await sequence.first { _ in true }
}
try await group.next()
}) { error in
XCTAssertEqual(error as? ChannelError, .alreadyClosed)
}
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
}
func testFinishError_whenStreaming_andNotSuspended_andBufferNotEmpty() async throws {
_ = self.source.yield(contentsOf: [1])
self.source.finish(ChannelError.alreadyClosed)
var elements = [Int]()
await XCTAssertThrowsError(try await {
for try await element in self.sequence {
elements.append(element)
}
}()) { error in
XCTAssertEqual(error as? ChannelError, .alreadyClosed)
}
XCTAssertEqual(elements, [1])
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
}
func testFinishError_whenFinished() async throws {
self.source.finish()
let iterator = self.sequence.makeAsyncIterator()
_ = try await iterator.next()
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
self.source.finish(ChannelError.alreadyClosed)
// This call should just return nil
_ = try await iterator.next()
}
// MARK: - Source Deinited
func testSourceDeinited_whenInitial() async {
self.source = nil
}
func testSourceDeinited_whenStreaming_andSuspended() async throws {
// We are registering our demand and sleeping a bit to make
// sure the other child task runs when the demand is registered
let sequence = try XCTUnwrap(self.sequence)
let element: Int? = try await withThrowingTaskGroup(of: Int?.self) { group in
group.addTask {
let element = try await sequence.first { _ in true }
return element
}
try await Task.sleep(nanoseconds: 1_000_000)
self.source = nil
return try await group.next() ?? nil
}
XCTAssertEqual(element, nil)
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
}
func testSourceDeinited_whenStreaming_andNotSuspended_andBufferEmpty() async throws {
_ = self.source.yield(contentsOf: [])
self.source = nil
let sequence = try XCTUnwrap(self.sequence)
let element: Int? = try await withThrowingTaskGroup(of: Int?.self) { group in
group.addTask {
return try await sequence.first { _ in true }
}
return try await group.next() ?? nil
}
XCTAssertNil(element)
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
}
func testSourceDeinited_whenStreaming_andNotSuspended_andBufferNotEmpty() async throws {
_ = self.source.yield(contentsOf: [1])
self.source = nil
let sequence = try XCTUnwrap(self.sequence)
let element: Int? = try await withThrowingTaskGroup(of: Int?.self) { group in
group.addTask {
return try await sequence.first { _ in true }
}
return try await group.next() ?? nil
}
XCTAssertEqual(element, 1)
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
}
// MARK: - Task cancel
func testTaskCancel_whenStreaming_andSuspended() async throws {
// We are registering our demand and sleeping a bit to make
// sure our task runs when the demand is registered
let sequence = try XCTUnwrap(self.sequence)
let task: Task<Int?, Error> = Task {
let iterator = sequence.makeAsyncIterator()
return try await iterator.next()
}
try await Task.sleep(nanoseconds: 1_000_000)
task.cancel()
let result = await task.result
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
await XCTAssertThrowsError(try result.get()) { error in
XCTAssertTrue(error is CancellationError)
}
}
@available(*, deprecated, message: "tests the deprecated custom generic failure type")
func testTaskCancel_whenStreaming_andSuspended_withCustomErrorType() async throws {
struct CustomError: Error {}
// We are registering our demand and sleeping a bit to make
// sure our task runs when the demand is registered
let backPressureStrategy = MockNIOElementStreamBackPressureStrategy()
let delegate = MockNIOBackPressuredStreamSourceDelegate()
let new = NIOThrowingAsyncSequenceProducer.makeSequence(
elementType: Int.self,
failureType: CustomError.self,
backPressureStrategy: backPressureStrategy,
delegate: delegate
)
let sequence = new.sequence
let task: Task<Int?, Error> = Task {
let iterator = sequence.makeAsyncIterator()
return try await iterator.next()
}
try await Task.sleep(nanoseconds: 1_000_000)
task.cancel()
let result = await task.result
XCTAssertEqualWithoutAutoclosure(await delegate.events.prefix(1).collect(), [.didTerminate])
try withExtendedLifetime(new.source) {
XCTAssertNil(try result.get())
}
}
func testTaskCancel_whenStreaming_andNotSuspended() async throws {
// We are registering our demand and sleeping a bit to make
// sure our task runs when the demand is registered
let sequence = try XCTUnwrap(self.sequence)
let task: Task<Int?, Error> = Task {
let iterator = sequence.makeAsyncIterator()
let element = try await iterator.next()
// Sleeping here to give the other Task a chance to cancel this one.
try? await Task.sleep(nanoseconds: 1_000_000)
return element
}
try await Task.sleep(nanoseconds: 1_000_000)
_ = self.source.yield(contentsOf: [1])
task.cancel()
let value = try await task.value
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
XCTAssertEqual(value, 1)
}
func testTaskCancel_whenSourceFinished() async throws {
// We are registering our demand and sleeping a bit to make
// sure our task runs when the demand is registered
let sequence = try XCTUnwrap(self.sequence)
let task: Task<Int?, Error> = Task {
let iterator = sequence.makeAsyncIterator()
return try await iterator.next()
}
try await Task.sleep(nanoseconds: 1_000_000)
self.source.finish()
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
task.cancel()
let value = try await task.value
XCTAssertNil(value)
}
func testTaskCancel_whenStreaming_andTaskIsAlreadyCancelled() async throws {
let sequence = try XCTUnwrap(self.sequence)
let task: Task<Int?, Error> = Task {
// We are sleeping here to allow some time for us to cancel the task.
// Once the Task is cancelled we will call `next()`
try? await Task.sleep(nanoseconds: 1_000_000)
let iterator = sequence.makeAsyncIterator()
return try await iterator.next()
}
task.cancel()
let result = await task.result
await XCTAssertThrowsError(try result.get()) { error in
XCTAssertTrue(error is CancellationError, "unexpected error \(error)")
}
}
@available(*, deprecated, message: "tests the deprecated custom generic failure type")
func testTaskCancel_whenStreaming_andTaskIsAlreadyCancelled_withCustomErrorType() async throws {
struct CustomError: Error {}
let backPressureStrategy = MockNIOElementStreamBackPressureStrategy()
let delegate = MockNIOBackPressuredStreamSourceDelegate()
let new = NIOThrowingAsyncSequenceProducer.makeSequence(
elementType: Int.self,
failureType: CustomError.self,
backPressureStrategy: backPressureStrategy,
delegate: delegate
)
let sequence = new.sequence
let task: Task<Int?, Error> = Task {
// We are sleeping here to allow some time for us to cancel the task.
// Once the Task is cancelled we will call `next()`
try? await Task.sleep(nanoseconds: 1_000_000)
let iterator = sequence.makeAsyncIterator()
return try await iterator.next()
}
task.cancel()
let result = await task.result
try withExtendedLifetime(new.source) {
XCTAssertNil(try result.get())
}
}
// MARK: - Next
func testNext_whenInitial_whenDemand() async throws {
self.backPressureStrategy.didNextHandler = { _ in true }
// We are registering our demand and sleeping a bit to make
// sure the other child task runs when the demand is registered
let sequence = try XCTUnwrap(self.sequence)
Task {
// Would prefer to use async let _ here but that is not allowed yet
_ = try await sequence.first { _ in true }
}
try await Task.sleep(nanoseconds: 1_000_000)
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didNext])
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.produceMore])
}
func testNext_whenInitial_whenNoDemand() async throws {
self.backPressureStrategy.didNextHandler = { _ in false }
// We are registering our demand and sleeping a bit to make
// sure the other child task runs when the demand is registered
let sequence = try XCTUnwrap(self.sequence)
Task {
// Would prefer to use async let _ here but that is not allowed yet
_ = try await sequence.first { _ in true }
}
try await Task.sleep(nanoseconds: 1_000_000)
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didNext])
}
func testNext_whenStreaming_whenEmptyBuffer_whenDemand() async throws {
self.backPressureStrategy.didNextHandler = { _ in true }
_ = self.source.yield(contentsOf: [])
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didYield])
// We are registering our demand and sleeping a bit to make
// sure the other child task runs when the demand is registered
let sequence = try XCTUnwrap(self.sequence)
Task {
// Would prefer to use async let _ here but that is not allowed yet
_ = try await sequence.first { _ in true }
}
try await Task.sleep(nanoseconds: 1_000_000)
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didNext])
}
func testNext_whenStreaming_whenEmptyBuffer_whenNoDemand() async throws {
self.backPressureStrategy.didNextHandler = { _ in false }
_ = self.source.yield(contentsOf: [])
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didYield])
// We are registering our demand and sleeping a bit to make
// sure the other child task runs when the demand is registered
let sequence = try XCTUnwrap(self.sequence)
Task {
// Would prefer to use async let _ here but that is not allowed yet
_ = try await sequence.first { _ in true }
}
try await Task.sleep(nanoseconds: 1_000_000)
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didNext])
}
func testNext_whenStreaming_whenNotEmptyBuffer_whenNoDemand() async throws {
self.backPressureStrategy.didNextHandler = { _ in false }
_ = self.source.yield(contentsOf: [1])
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didYield])
let element = try await self.sequence.first { _ in true }
XCTAssertEqual(element, 1)
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didNext])
}
func testNext_whenStreaming_whenNotEmptyBuffer_whenNewDemand() async throws {
self.backPressureStrategy.didNextHandler = { _ in true }
_ = self.source.yield(contentsOf: [1])
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didYield])
let element = try await self.sequence.first { _ in true }
XCTAssertEqual(element, 1)
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didNext])
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.produceMore])
}
func testNext_whenStreaming_whenNotEmptyBuffer_whenNewAndOutstandingDemand() async throws {
self.backPressureStrategy.didNextHandler = { _ in true }
self.backPressureStrategy.didYieldHandler = { _ in true }
_ = self.source.yield(contentsOf: [1])
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didYield])
let element = try await self.sequence.first { _ in true }
XCTAssertEqual(element, 1)
XCTAssertEqualWithoutAutoclosure(await self.backPressureStrategy.events.prefix(1).collect(), [.didNext])
}
func testNext_whenSourceFinished() async throws {
_ = self.source.yield(contentsOf: [1, 2])
self.source.finish()
var elements = [Int]()
for try await element in self.sequence {
elements.append(element)
}
XCTAssertEqual(elements, [1, 2])
}
// MARK: - SequenceDeinitialized
func testSequenceDeinitialized() async {
self.sequence = nil
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
}
func testSequenceDeinitialized_whenIteratorReferenced() async {
var iterator = self.sequence?.makeAsyncIterator()
self.sequence = nil
XCTAssertNotNil(iterator)
iterator = nil
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
}
// MARK: - IteratorDeinitialized
func testIteratorDeinitialized_whenSequenceReferenced() async {
var iterator = self.sequence?.makeAsyncIterator()
XCTAssertNotNil(iterator)
iterator = nil
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
self.sequence = nil
}
func testIteratorDeinitialized_whenSequenceFinished() async {
self.source.finish()
var iterator = self.sequence?.makeAsyncIterator()
XCTAssertNotNil(iterator)
iterator = nil
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
}
func testIteratorDeinitialized_whenStreaming() async {
_ = self.source.yield(contentsOf: [1])
var iterator = self.sequence?.makeAsyncIterator()
XCTAssertNotNil(iterator)
iterator = nil
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
}
func testIteratorThrows_whenCancelled() async {
_ = self.source.yield(contentsOf: Array(0..<100))
await withThrowingTaskGroup(of: Void.self) { group in
group.addTask {
var counter = 0
guard let sequence = self.sequence else {
return XCTFail("Expected to have an AsyncSequence")
}
do {
for try await next in sequence {
XCTAssertEqual(next, counter)
counter += 1
}
XCTFail("Expected that this throws")
} catch is CancellationError {
// expected
} catch {
XCTFail("Unexpected error: \(error)")
}
XCTAssertLessThan(counter, 100)
}
group.cancelAll()
}
XCTAssertEqualWithoutAutoclosure(await self.delegate.events.prefix(1).collect(), [.didTerminate])
}
}
// This is needed until async let is supported to be used in autoclosures
fileprivate func XCTAssertEqualWithoutAutoclosure<T>(
_ expression1: T,
_ expression2: T,
_ message: @autoclosure () -> String = "",
file: StaticString = #filePath,
line: UInt = #line
) where T: Equatable {
XCTAssertEqual(expression1, expression2, message(), file: file, line: line)
}
extension AsyncSequence {
/// Collect all elements in the sequence into an array.
fileprivate func collect() async rethrows -> [Element] {
try await self.reduce(into: []) { accumulated, next in
accumulated.append(next)
}
}
}