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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift Async Algorithms open source project
//
// Copyright (c) 2022 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
//
//===----------------------------------------------------------------------===//
import XCTest
import AsyncAlgorithms
final class TestChain2: XCTestCase {
func test_chain2_concatenates_elements_from_sequences_and_returns_nil_when_source_is_pastEnd() async {
let expected1 = [1, 2, 3]
let expected2 = [4, 5, 6]
let expected = expected1 + expected2
let chained = chain(expected1.async, expected2.async)
var iterator = chained.makeAsyncIterator()
var collected = [Int]()
while let item = await iterator.next() {
collected.append(item)
}
XCTAssertEqual(expected, collected)
let pastEnd = await iterator.next()
XCTAssertNil(pastEnd)
}
func test_chain2_outputs_elements_from_first_sequence_and_throws_when_first_throws() async throws {
let chained = chain([1, 2, 3].async.map { try throwOn(3, $0) }, [4, 5, 6].async)
var iterator = chained.makeAsyncIterator()
var collected = [Int]()
do {
while let item = try await iterator.next() {
collected.append(item)
}
XCTFail("Chained sequence should throw when first sequence throws")
} catch {
XCTAssertEqual(Failure(), error as? Failure)
}
XCTAssertEqual([1, 2], collected)
let pastEnd = try await iterator.next()
XCTAssertNil(pastEnd)
}
func test_chain2_outputs_elements_from_sequences_and_throws_when_second_throws() async throws {
let chained = chain([1, 2, 3].async, [4, 5, 6].async.map { try throwOn(5, $0) })
var iterator = chained.makeAsyncIterator()
var collected = [Int]()
do {
while let item = try await iterator.next() {
collected.append(item)
}
XCTFail("Chained sequence should throw when second sequence throws")
} catch {
XCTAssertEqual(Failure(), error as? Failure)
}
XCTAssertEqual(collected, [1, 2, 3, 4])
let pastEnd = try await iterator.next()
XCTAssertNil(pastEnd)
}
func test_chain2_finishes_when_task_is_cancelled() async {
let finished = expectation(description: "finished")
let iterated = expectation(description: "iterated")
let source = Indefinite(value: "test")
let sequence = chain(source.async, ["past indefinite"].async)
let task = Task {
var firstIteration = false
for await _ in sequence {
if !firstIteration {
firstIteration = true
iterated.fulfill()
}
}
finished.fulfill()
}
// ensure the other task actually starts
await fulfillment(of: [iterated], timeout: 1.0)
// cancellation should ensure the loop finishes
// without regards to the remaining underlying sequence
task.cancel()
await fulfillment(of: [finished], timeout: 1.0)
}
}
final class TestChain3: XCTestCase {
func test_chain3_concatenates_elements_from_sequences_and_returns_nil_when_source_is_pastEnd() async {
let expected1 = [1, 2, 3]
let expected2 = [4, 5, 6]
let expected3 = [7, 8, 9]
let expected = expected1 + expected2 + expected3
let chained = chain(expected1.async, expected2.async, expected3.async)
var iterator = chained.makeAsyncIterator()
var collected = [Int]()
while let item = await iterator.next() {
collected.append(item)
}
XCTAssertEqual(expected, collected)
let pastEnd = await iterator.next()
XCTAssertNil(pastEnd)
}
func test_chain3_outputs_elements_from_first_sequence_and_throws_when_first_throws() async throws {
let chained = chain([1, 2, 3].async.map { try throwOn(3, $0) }, [4, 5, 6].async, [7, 8, 9].async)
var iterator = chained.makeAsyncIterator()
var collected = [Int]()
do {
while let item = try await iterator.next() {
collected.append(item)
}
XCTFail("Chained sequence should throw when first sequence throws")
} catch {
XCTAssertEqual(Failure(), error as? Failure)
}
XCTAssertEqual(collected, [1, 2])
let pastEnd = try await iterator.next()
XCTAssertNil(pastEnd)
}
func test_chain3_outputs_elements_from_sequences_and_throws_when_second_throws() async throws {
let chained = chain([1, 2, 3].async, [4, 5, 6].async.map { try throwOn(5, $0) }, [7, 8, 9].async)
var iterator = chained.makeAsyncIterator()
var collected = [Int]()
do {
while let item = try await iterator.next() {
collected.append(item)
}
XCTFail("Chained sequence should throw when second sequence throws")
} catch {
XCTAssertEqual(Failure(), error as? Failure)
}
XCTAssertEqual(collected, [1, 2, 3, 4])
let pastEnd = try await iterator.next()
XCTAssertNil(pastEnd)
}
func test_chain3_outputs_elements_from_sequences_and_throws_when_third_throws() async throws {
let chained = chain([1, 2, 3].async, [4, 5, 6].async, [7, 8, 9].async.map { try throwOn(8, $0) })
var iterator = chained.makeAsyncIterator()
var collected = [Int]()
do {
while let item = try await iterator.next() {
collected.append(item)
}
XCTFail("Chained sequence should throw when third sequence throws")
} catch {
XCTAssertEqual(Failure(), error as? Failure)
}
XCTAssertEqual(collected, [1, 2, 3, 4, 5, 6, 7])
let pastEnd = try await iterator.next()
XCTAssertNil(pastEnd)
}
func test_chain3_finishes_when_task_is_cancelled() async {
let finished = expectation(description: "finished")
let iterated = expectation(description: "iterated")
let source = Indefinite(value: "test")
let sequence = chain(source.async, ["past indefinite"].async, ["and even further"].async)
let task = Task {
var firstIteration = false
for await _ in sequence {
if !firstIteration {
firstIteration = true
iterated.fulfill()
}
}
finished.fulfill()
}
// ensure the other task actually starts
await fulfillment(of: [iterated], timeout: 1.0)
// cancellation should ensure the loop finishes
// without regards to the remaining underlying sequence
task.cancel()
await fulfillment(of: [finished], timeout: 1.0)
}
}
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