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Copy pathlinked-list.spec.ts
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linked-list.spec.ts
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import 'mocha';
import { expect } from 'chai';
import { LinkedList, util } from '../../../src/ts/index';
import MyObj from './my-obj';
describe('LinkedList', () => {
let list: LinkedList<number>;
let min: number;
let max: number;
beforeEach(() => {
list = new LinkedList<number>(util.defaultEquals);
min = 1;
max = 3;
});
function pushesElements() {
for (let i = min; i <= max; i++) {
list.push(i);
}
}
function verifyList() {
let current = list.getHead();
for (let i = min; i <= max && current; i++) {
expect(current).to.not.be.an('undefined');
if (current) {
// TS strictNullChecks
expect(current.element).to.not.be.an('undefined');
expect(current.element).to.equal(i);
if (i < max) {
expect(current.next).to.not.be.an('undefined');
if (current.next) {
// TS strictNullChecks
expect(current.next.element).to.equal(i + 1);
}
} else {
expect(current.next).to.be.an('undefined');
}
current = current.next;
}
}
}
it('starts empty', () => {
expect(list.size()).to.equal(0);
expect(list.isEmpty()).to.equal(true);
expect(list.getHead()).to.be.an('undefined');
});
it('pushes elements', () => {
pushesElements();
verifyList();
});
it('returns element at specific index: invalid position', () => {
// list is empty
expect(list.getElementAt(3)).to.be.an('undefined');
});
it('returns element at specific index', () => {
let node;
pushesElements();
for (let i = min; i <= max; i++) {
node = list.getElementAt(i - 1);
expect(node).to.not.be.an('undefined');
if (node) {
expect(node.element).to.equal(i);
}
}
});
it('inserts elements first position empty list', () => {
const element = 1;
max = element;
expect(list.insert(element, 0)).to.equal(true);
verifyList();
});
it('inserts elements first position not empty list', () => {
max = 2;
expect(list.insert(max, 0)).to.equal(true);
expect(list.insert(min, 0)).to.equal(true);
verifyList();
});
it('inserts elements invalid position empty list', () => {
expect(list.insert(1, 1)).to.equal(false);
});
it('inserts elements invalid position not empty list', () => {
const element = 1;
expect(list.insert(element, 0)).to.equal(true);
expect(list.insert(element, 2)).to.equal(false);
});
it('inserts elements in the middle of list', () => {
expect(list.insert(3, 0)).to.equal(true);
expect(list.insert(1, 0)).to.equal(true);
expect(list.insert(2, 1)).to.equal(true);
verifyList();
});
it('inserts elements at the end of list', () => {
max = 5;
for (let i = min; i <= max; i++) {
expect(list.insert(i , i - 1)).to.equal(true);
}
verifyList();
});
it('returns index of elements', () => {
let index;
pushesElements();
for (let i = min; i <= max; i++) {
index = list.indexOf(i);
expect(index).to.equal(i - 1);
}
expect(list.indexOf(max + 2)).to.equal(-1);
});
it('removes valid elements', () => {
let element;
pushesElements();
for (let i = min; i <= max; i++) {
element = list.remove(i);
expect(element).to.not.be.an('undefined');
expect(element).to.equal(i);
}
});
it('removes invalid elements', () => {
let element;
pushesElements();
for (let i = max + 2; i <= max + 4; i++) {
element = list.remove(i);
expect(element).to.be.an('undefined');
}
});
it('removes element invalid position empty list', () => {
let element;
for (let i = min; i <= max; i++) {
element = list.removeAt(i - 1);
expect(element).to.be.an('undefined');
}
});
it('removes element invalid position not empty list', () => {
let element;
pushesElements();
for (let i = max + 2; i <= max + 4; i++) {
element = list.removeAt(i);
expect(element).to.be.an('undefined');
}
});
it('removes first element list single element', () => {
const value = 1;
list.push(value);
const element = list.removeAt(0);
expect(element).to.not.be.an('undefined');
expect(element).to.equal(value);
expect(list.getHead()).to.be.an('undefined');
expect(list.isEmpty()).to.equal(true);
});
it('removes first element list multiple elements', () => {
pushesElements();
const element = list.removeAt(0);
expect(element).to.not.be.an('undefined');
expect(element).to.equal(min);
min = 2;
verifyList();
});
it('removes element from middle of list', () => {
pushesElements(); // 1, 2, 3
const element = list.removeAt(1); // element 2
expect(element).to.not.be.an('undefined');
expect(element).to.equal(2);
// list needs to be [1, 3]
let current = list.getHead();
// element 1
expect(current).to.not.be.an('undefined');
if (current) {
expect(current.element).to.not.be.an('undefined');
expect(current.element).to.equal(1);
expect(current.next).to.not.be.an('undefined');
if (current.next) {
expect(current.next.element).to.equal(3);
current = current.next;
}
}
// element 3
expect(current).to.not.be.an('undefined');
if (current) {
expect(current.element).to.not.be.an('undefined');
expect(current.element).to.equal(3);
expect(current.next).to.be.an('undefined');
}
});
it('removes element from end of list', () => {
let element;
pushesElements();
const maxIndex = max;
for (let i = maxIndex; i >= min; i--) {
element = list.removeAt(i - 1);
expect(element).to.not.be.an('undefined');
expect(element).to.equal(i);
max--;
verifyList();
}
});
it('returns the head of the list', () => {
expect(list.getHead()).to.be.an('undefined');
list.push(1);
expect(list.getHead()).to.not.be.an('undefined');
});
it('returns the correct size', () => {
expect(list.size()).to.equal(0);
for (let i = min; i <= max; i++) {
list.push(i);
expect(list.size()).to.equal(i);
}
const size = max;
for (let i = min; i <= max; i++) {
list.remove(i);
expect(list.size()).to.equal(size - i);
}
expect(list.size()).to.equal(0);
});
it('returns if it is empty', () => {
expect(list.isEmpty()).to.equal(true);
for (let i = min; i <= max; i++) {
list.push(i);
expect(list.isEmpty()).to.equal(false);
}
for (let i = min; i < max; i++) {
list.remove(i);
expect(list.isEmpty()).to.equal(false);
}
list.remove(max);
expect(list.isEmpty()).to.equal(true);
pushesElements();
expect(list.isEmpty()).to.equal(false);
list.clear();
expect(list.isEmpty()).to.equal(true);
});
it('clears the list', () => {
expect(list.size()).to.equal(0);
list.clear();
expect(list.size()).to.equal(0);
pushesElements();
expect(list.size()).to.greaterThan(0);
list.clear();
expect(list.size()).to.equal(0);
});
it('returns toString primitive types', () => {
expect(list.toString()).to.equal('');
list.push(1);
expect(list.toString()).to.equal('1');
list.push(2);
expect(list.toString()).to.equal('1,2');
list.clear();
expect(list.toString()).to.equal('');
});
it('returns toString primitive types: string', () => {
const ds = new LinkedList<string>();
ds.push('el1');
expect(ds.toString()).to.equal('el1');
ds.push('el2');
expect(ds.toString()).to.equal('el1,el2');
});
it('returns toString objects', () => {
const ds = new LinkedList<MyObj>();
expect(ds.toString()).to.equal('');
ds.push(new MyObj(1, 2));
expect(ds.toString()).to.equal('1|2');
ds.push(new MyObj(3, 4));
expect(ds.toString()).to.equal('1|2,3|4');
});
});