dev@508: import { PersistentStack } from '../../src/app/Session';
dev@508: import * as jasmine from 'jasmine-core';
dev@508: 
dev@508: describe('PersistentStack', () => {
dev@508:   it('can add values to the front and maintain undo history', () => {
dev@508:     const stack = new PersistentStack<number>();
dev@508:     stack.unshift(1);
dev@508:     stack.unshift(2);
dev@508:     expect(stack.get(0)).toBe(2);
dev@508:     expect(stack.get(1)).toBe(1);
dev@508:     stack.stepBack();
dev@508:     expect(stack.get(0)).toBe(1);
dev@508:     expect(stack.get(1)).toBeUndefined();
dev@508:   });
dev@508: });
dev@508: