test: add IntroSort tests #1862

Original file line number	Diff line number	Diff line change
Expand Up		@@ -241,69 +241,4 @@ function introsort(array, compare) {
		})(array, compare)
		}

	/**
	* @example Demo run of the sort routine
	* The data is randomly generated
	* Returns 'RIGHT:)' if the sort routine worked as expected,
	* 'WRONG!!' otherwise
	*/
	function demo1() {
	const data = []
	const size = 1000000
	let i = 0
	let temp
	const c = function (a, b) {
	return a - b
	}
	for (i = 0; i < size; i++) {
	temp = Math.random() * Number.MAX_SAFE_INTEGER
	data.push(temp)
	}
	introsort(data, c)
	let faulty = false
	for (i = 1; i < size; i++) {
	if (data[i] < data[i - 1]) {
	faulty = true
	break
	}
	}
	if (faulty) {
	return 'WRONG!!'
	} else {
	return 'RIGHT:)'
	}
	}

	/**
	* @example Demo run of the sort routine
	* using the default compare function and
	* comparing the results with Array.sort
	*/
	function demo2() {
	const data = []
	const data2 = []
	const size = 1000000
	let i = 0
	let temp
	for (i = 0; i < size; i++) {
	temp = Math.random() * Number.MAX_SAFE_INTEGER
	data.push(temp)
	data2.push(temp)
	}
	introsort(data)
	data2.sort()
	let faulty = false
	for (i = 1; i < size; i++) {
	if (data[i] !== data2[i]) {
	faulty = true
	break
	}
	}
	if (faulty) {
	return 'WRONG Implemented Comparator!!'
	} else {
	return 'Comparator Works Fine:)'
	}
	}

	export { introsort, demo1, demo2 }
	export { introsort }

74 changes: 74 additions & 0 deletions Sorts/test/IntroSort.test.js

Show comments View file Open in desktop

Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,74 @@
	import { introsort } from '../IntroSort'

	describe('introsort', () => {
	it('should have a robust default comparator', () => {
	// toString, null, undefined
	const mixedData = [undefined, '2', 1, false, null, { a: 7 }]
	introsort(mixedData)
	expect(mixedData).toEqual([1, '2', { a: 7 }, false, null, undefined])

	// Symbol
	expect(() => introsort([Symbol(), Symbol()])).toThrowError()
	})

	it('fails gracefully', () => {
	introsort('string')
	introsort([])
	introsort(['one len'])
	introsort([1, 2, 3], 'string')
	})

	it('should sort randomly generated data', function demo1() {
	// make array
	const data = []
	const size = 10_000
	for (let i = 0; i < size; i++) {
	const temp = Math.random() * Number.MAX_SAFE_INTEGER
	data.push(temp)
	}

	// custom comparator
	const c = function (a, b) {
	return a - b
	}
	introsort(data, c)

	// check that all numbers are smaller than the one after them
	let faulty = false
	for (let i = 1; i < size; i++) {
	if (data[i - 1] > data[i]) {
	faulty = true
	break
	}
	}

	expect(faulty).toEqual(false)
	})

	it('should match the sorting of Array.sort()', function demo2() {
	// make arrays
	const data = []
	const data2 = []
	const size = 10_000
	for (let i = 0; i < size; i++) {
	const temp = Math.random() * Number.MAX_SAFE_INTEGER
	data.push(temp)
	data2.push(temp)
	}

	// sort
	introsort(data)
	data2.sort()

	// verify
	let faulty = false
	for (let i = 0; i < size; i++) {
	if (data[i] !== data2[i]) {
	faulty = true
	break
	}
	}

	expect(faulty).toEqual(false)
	})
	})

Navigation Menu