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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 TestBuffer: XCTestCase {
func test_given_a_base_sequence_when_buffering_with_unbounded_then_the_buffer_is_filled_in() async {
// Given
var base = GatedSequence([1, 2, 3, 4, 5])
let buffered = base.buffer(policy: .unbounded)
var iterator = buffered.makeAsyncIterator()
// When
base.advance()
// Then
var value = await iterator.next()
XCTAssertEqual(value, 1)
// When
base.advance()
base.advance()
base.advance()
// Then
value = await iterator.next()
XCTAssertEqual(value, 2)
value = await iterator.next()
XCTAssertEqual(value, 3)
value = await iterator.next()
XCTAssertEqual(value, 4)
// When
base.advance()
base.advance()
// Then
value = await iterator.next()
XCTAssertEqual(value, 5)
value = await iterator.next()
XCTAssertEqual(value, nil)
let pastEnd = await iterator.next()
XCTAssertEqual(value, pastEnd)
}
func test_given_a_failable_base_sequence_when_buffering_with_unbounded_then_the_failure_is_forwarded() async {
// Given
var gated = GatedSequence([1, 2, 3, 4, 5, 6, 7])
let base = gated.map { try throwOn(3, $0) }
let buffered = base.buffer(policy: .unbounded)
var iterator = buffered.makeAsyncIterator()
// When
gated.advance()
// Then
var value = try! await iterator.next()
XCTAssertEqual(value, 1)
// When
gated.advance()
gated.advance()
gated.advance()
// Then
value = try! await iterator.next()
XCTAssertEqual(value, 2)
// When
gated.advance()
gated.advance()
gated.advance()
gated.advance()
// Then
do {
value = try await iterator.next()
XCTFail("next() should have thrown.")
} catch {
XCTAssert(error is Failure)
}
var pastFailure = try! await iterator.next()
XCTAssertNil(pastFailure)
pastFailure = try! await iterator.next()
XCTAssertNil(pastFailure)
pastFailure = try! await iterator.next()
XCTAssertNil(pastFailure)
pastFailure = try! await iterator.next()
XCTAssertNil(pastFailure)
pastFailure = try! await iterator.next()
XCTAssertNil(pastFailure)
}
func test_given_a_base_sequence_when_bufferingOldest_then_the_policy_is_applied() async {
validate {
"X-12- 34- 5 |"
$0.inputs[0].buffer(policy: .bufferingOldest(2))
"X,,,[1,],,[2,],[3,][5,]|"
}
}
func test_given_a_base_sequence_when_bufferingOldest_with_0_limit_then_the_policy_is_transparent() async {
validate {
"X-12- 34- 5 |"
$0.inputs[0].buffer(policy: .bufferingOldest(0))
"X-12- 34- 5 |"
}
}
func test_given_a_base_sequence_when_bufferingOldest_at_slow_pace_then_no_element_is_dropped() async {
validate {
"X-12 3 4 5 |"
$0.inputs[0].buffer(policy: .bufferingOldest(2))
"X,,[1,][2,][3,][45]|"
}
}
func test_given_a_failable_base_sequence_when_bufferingOldest_then_the_failure_is_forwarded() async {
validate {
"X-12345^"
$0.inputs[0].buffer(policy: .bufferingOldest(2))
"X,,,,,,[12^]"
}
}
func test_given_a_base_sequence_when_bufferingNewest_then_the_policy_is_applied() async {
validate {
"X-12- 34 -5|"
$0.inputs[0].buffer(policy: .bufferingLatest(2))
"X,,,[1,],,[3,],[4,][5,]|"
}
}
func test_given_a_base_sequence_when_bufferingNewest_with_limit_0_then_the_policy_is_transparent() async {
validate {
"X-12- 34 -5|"
$0.inputs[0].buffer(policy: .bufferingLatest(0))
"X-12- 34 -5|"
}
}
func test_given_a_base_sequence_when_bufferingNewest_at_slow_pace_then_no_element_is_dropped() async {
validate {
"X-12 3 4 5 |"
$0.inputs[0].buffer(policy: .bufferingLatest(2))
"X,,[1,][2,][3,][45]|"
}
}
func test_given_a_failable_base_sequence_when_bufferingNewest_then_the_failure_is_forwarded() async {
validate {
"X-12345^"
$0.inputs[0].buffer(policy: .bufferingLatest(2))
"X,,,,,,[45^]"
}
}
func test_given_a_buffered_with_unbounded_sequence_when_cancelling_consumer_then_the_iteration_finishes_and_the_base_is_cancelled() async {
// Given
let buffered = Indefinite(value: 1).async.buffer(policy: .unbounded)
let finished = expectation(description: "finished")
let iterated = expectation(description: "iterated")
let task = Task {
var firstIteration = false
for await _ in buffered {
if !firstIteration {
firstIteration = true
iterated.fulfill()
}
}
finished.fulfill()
}
// ensure the task actually starts
await fulfillment(of: [iterated], timeout: 1.0)
// When
task.cancel()
// Then
await fulfillment(of: [finished], timeout: 1.0)
}
func test_given_a_base_sequence_when_buffering_with_bounded_then_the_buffer_is_filled_in_and_suspends() async {
// Gicen
var base = GatedSequence([1, 2, 3, 4, 5])
let buffered = base.buffer(policy: .bounded(2))
var iterator = buffered.makeAsyncIterator()
// When
base.advance()
// Then
var value = await iterator.next()
XCTAssertEqual(value, 1)
// When
base.advance()
base.advance()
base.advance()
// Then
value = await iterator.next()
XCTAssertEqual(value, 2)
value = await iterator.next()
XCTAssertEqual(value, 3)
value = await iterator.next()
XCTAssertEqual(value, 4)
// When
base.advance()
base.advance()
// Then
value = await iterator.next()
XCTAssertEqual(value, 5)
value = await iterator.next()
XCTAssertEqual(value, nil)
let pastEnd = await iterator.next()
XCTAssertEqual(value, pastEnd)
}
func test_given_a_failable_base_sequence_when_buffering_with_bounded_then_the_failure_is_forwarded() async {
// Given
var gated = GatedSequence([1, 2, 3, 4, 5, 6, 7])
let base = gated.map { try throwOn(3, $0) }
let buffered = base.buffer(policy: .bounded(5))
var iterator = buffered.makeAsyncIterator()
// When
gated.advance()
// Then
var value = try! await iterator.next()
XCTAssertEqual(value, 1)
// When
gated.advance()
gated.advance()
gated.advance()
// Then
value = try! await iterator.next()
XCTAssertEqual(value, 2)
// When
gated.advance()
gated.advance()
gated.advance()
gated.advance()
// Then
do {
value = try await iterator.next()
XCTFail("next() should have thrown.")
} catch {
XCTAssert(error is Failure)
}
var pastFailure = try! await iterator.next()
XCTAssertNil(pastFailure)
pastFailure = try! await iterator.next()
XCTAssertNil(pastFailure)
pastFailure = try! await iterator.next()
XCTAssertNil(pastFailure)
pastFailure = try! await iterator.next()
XCTAssertNil(pastFailure)
pastFailure = try! await iterator.next()
XCTAssertNil(pastFailure)
}
func test_given_a_buffered_bounded_sequence_when_cancelling_consumer_then_the_iteration_finishes_and_the_base_is_cancelled() async {
// Given
let buffered = Indefinite(value: 1).async.buffer(policy: .bounded(3))
let finished = expectation(description: "finished")
let iterated = expectation(description: "iterated")
let task = Task {
var firstIteration = false
for await _ in buffered {
if !firstIteration {
firstIteration = true
iterated.fulfill()
}
}
finished.fulfill()
}
// ensure the other task actually starts
await fulfillment(of: [iterated], timeout: 1.0)
// When
task.cancel()
// Then
await fulfillment(of: [finished], timeout: 1.0)
}
func test_given_a_base_sequence_when_bounded_with_limit_0_then_the_policy_is_transparent() async {
validate {
"X-12- 34 -5|"
$0.inputs[0].buffer(policy: .bounded(0))
"X-12- 34 -5|"
}
}
}
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