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//===----------------------------------------------------------------------===//
//
// This source file is part of the SwiftNIO open source project
//
// Copyright (c) 2017-2020 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 XCTest
@testable import NIO
class PriorityQueueTest: XCTestCase {
func testSomeStringsAsc() throws {
var pq = PriorityQueue<String>()
pq.push("foo")
pq.push("bar")
pq.push("buz")
pq.push("qux")
pq.remove("buz")
XCTAssertEqual("bar", pq.peek()!)
XCTAssertEqual("bar", pq.pop()!)
pq.push("bar")
XCTAssertEqual("bar", pq.peek()!)
XCTAssertEqual("bar", pq.pop()!)
XCTAssertEqual("foo", pq.pop()!)
XCTAssertEqual("qux", pq.pop()!)
XCTAssertTrue(pq.isEmpty)
}
func testRemoveNonExisting() throws {
var pq = PriorityQueue<String>()
pq.push("foo")
pq.remove("bar")
pq.remove("foo")
XCTAssertNil(pq.pop())
XCTAssertNil(pq.peek())
}
func testRemoveFromEmpty() throws {
var pq = PriorityQueue<Int>()
pq.remove(234)
XCTAssertTrue(pq.isEmpty)
}
func testBuildAndRemoveFromRandomPriorityQueues() {
for size in 0...33 {
var pq = PriorityQueue<UInt8>()
let randoms = getRandomNumbers(count: size)
randoms.forEach { pq.push($0) }
/* remove one random member, add it back and assert we're still the same */
randoms.forEach { random in
var pq2 = pq
pq2.remove(random)
XCTAssertEqual(pq.count - 1, pq2.count)
XCTAssertNotEqual(pq, pq2)
pq2.push(random)
XCTAssertEqual(pq, pq2)
}
/* remove up to `n` members and add them back at the end and check that the priority queues are still the same */
for n in 1...5 where n <= size {
var pq2 = pq
let deleted = randoms.prefix(n).map { (random: UInt8) -> UInt8 in
pq2.remove(random)
return random
}
XCTAssertEqual(pq.count - n, pq2.count)
XCTAssertNotEqual(pq, pq2)
deleted.reversed().forEach { pq2.push($0) }
XCTAssertEqual(pq, pq2, "pq: \(pq), pq2: \(pq2), deleted: \(deleted)")
}
}
}
func testPartialOrder() {
let clearlyTheSmallest = SomePartiallyOrderedDataType(width: 0, height: 0)
let clearlyTheLargest = SomePartiallyOrderedDataType(width: 100, height: 100)
let inTheMiddles = zip(1...99, (1...99).reversed()).map { SomePartiallyOrderedDataType(width: $0, height: $1) }
/*
the four values are only partially ordered (from small (top) to large (bottom)):
clearlyTheSmallest
/ | \
inTheMiddle[0] | inTheMiddle[1...]
\ | /
clearlyTheLargest
*/
var pq = PriorityQueue<SomePartiallyOrderedDataType>()
pq.push(clearlyTheLargest)
pq.push(inTheMiddles[0])
pq.push(clearlyTheSmallest)
inTheMiddles[1...].forEach {
pq.push($0)
}
let pop1 = pq.pop()
XCTAssertEqual(clearlyTheSmallest, pop1)
for _ in inTheMiddles {
let popN = pq.pop()!
XCTAssert(inTheMiddles.contains(popN))
}
XCTAssertEqual(clearlyTheLargest, pq.pop()!)
XCTAssert(pq.isEmpty)
}
func testDescription() {
let pq1 = PriorityQueue<Int>()
var pq2 = PriorityQueue<Int>()
pq2.push(1)
pq2.push(2)
pq2.push(3)
XCTAssertEqual(pq1.description, "PriorityQueue(count: 0): \(Array(pq1))")
XCTAssertEqual(pq2.description, "PriorityQueue(count: 3): \(Array(pq2))")
}
}
/// This data type is only partially ordered. Ie. from `a < b` and `a != b` we can't imply `a > b`.
struct SomePartiallyOrderedDataType: Comparable, CustomStringConvertible {
public static func <(lhs: SomePartiallyOrderedDataType, rhs: SomePartiallyOrderedDataType) -> Bool {
return lhs.width < rhs.width && lhs.height < rhs.height
}
public static func ==(lhs: SomePartiallyOrderedDataType, rhs: SomePartiallyOrderedDataType) -> Bool {
return lhs.width == rhs.width && lhs.height == rhs.height
}
private let width: Int
private let height: Int
public init(width: Int, height: Int) {
self.width = width
self.height = height
}
public var description: String {
return "(w: \(self.width), h: \(self.height))"
}
}
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