data-structures/tests/Heap.spec.coffee

JavaScript data structures written in CoffeeScript.

Heap = require('../source').Heap

# Shorthand for logging.
l = (x) -> console.log require('util').inspect x, true, 10

extractMinsAndValidate = (heap, output) ->
  i = 0
  actualOutput = []
  while heap.peekMin()?
    actualOutput[i] = heap.removeMin()
    i++
  expect(actualOutput).toEqual output

describe "Add, peek minimum and remove it", ->
  heap = new Heap()
  it "should return undefined if minimum is not found (heap empty)", ->
    expect(heap.peekMin()).toBeUndefined()
    expect(heap.removeMin()).toBeUndefined()
  it "should discard undefined and null", ->
    expect(heap.add undefined).toBeUndefined()
    expect(heap.add 0).toBe 0
    expect(heap.add null).toBeUndefined()
    heap.add 9
    heap.add 8
    extractMinsAndValidate heap, [0, 8, 9]
  heap2 = new Heap()
  it "should return the value added, even negative ones", ->
    expect(heap2.add -1).toBe -1
    expect(heap2.add 0).toBe 0
    expect(heap2.add -2).toBe -2
    heap2.add undefined
    heap2.add -10
    heap2.add 4
    heap2.add 9
    heap2.add undefined
    heap2.add 99
    heap2.add -6
    heap2.add 8
    heap2.add 7
  it "should have the correct minimum", ->
    extractMinsAndValidate heap2, [-10, -6, -2, -1, 0, 4, 7, 8, 9, 99]

describe "Size checking", ->
  heap = new Heap()
  it "should have a size of 0 initially", ->
    expect(heap.size).toBe 0
  it "should have the right size after insertion and deletion", ->
    heap.add 1
    expect(heap.size).toBe 1
    heap.add 5
    expect(heap.size).toBe 2
    heap.add undefined
    expect(heap.size).toBe 2
    heap.removeMin()
    expect(heap.size).toBe 1
    heap.add 5
    expect(heap.size).toBe 2
  it "should have a size back to 0 when heap's emptied", ->
    heap.removeMin()
    heap.removeMin()
    expect(heap.size).toBe 0
  it "should not have a negative value", ->
    heap.removeMin()
    expect(heap.size).toBe 0
    heap.removeMin()
    expect(heap.size).toBe 0
  heap2 = new Heap([1, 2, undefined, 3])
  it "should be initialized well", ->
    expect(heap2.size).toBe 3

describe "Initialization passing an array", ->
  heap = new Heap([-3, undefined, 4, 6, -8, null, 5, -3, 2, 5, 6, -7])
  it "should heapify the array", ->
    extractMinsAndValidate heap, [-8, -7, -3, -3, 2, 4, 5, 5, 6, 6]