ahmedgaafer/JS-Data-Structures

import { Queue } from ".";

describe("Queue", () => {
    describe("Queue expected cases", () => {
        it("queue.constructor", () => {
            const q = new Queue([1, 2, 3]);
            expect(q).toBeDefined();
            expect(q._data[0]).toBe(1);
            expect(q._data[2]).toBe(3);
        });

        it("queue.enqueue", () => {
            const q = new Queue();
            q.enqueue(1).enqueue(2).enqueue(3);
            expect(q._data[0]).toBe(1);
            expect(q._data[2]).toBe(3);
        });

        it("queue.dequeue", () => {
            const q = new Queue();
            q.enqueue(1).enqueue(2).enqueue(3).dequeue();
            expect(q._data[0]).toBe(2);
            expect(q._data[1]).toBe(3);
            expect(q._data[2]).toBe(undefined);
        });

        it("queue.first", () => {
            const q = new Queue();
            q.enqueue(1).enqueue(2).enqueue(3);

            expect(q.first()).toBe(1);
        });

        it("queue.last", () => {
            const q = new Queue();
            q.enqueue(1).enqueue(2).enqueue(3);

            expect(q.last()).toBe(3);
        });

        it("queue.view", () => {
            const consoleSpy = jest.spyOn(console, "log");
            const q = new Queue();
            q.enqueue(1).enqueue(2).enqueue(3).view();

            expect(consoleSpy).toBeCalledTimes(1);
        });

        it("queue.getSize", () => {
            const q = new Queue();
            q.enqueue(1).enqueue(2).enqueue(3);
            expect(q.getSize()).toBe(3);
            q.dequeue().dequeue().dequeue();
            expect(q.getSize()).toBe(0);
        });
    });

    describe("Queue un-expected cases", () => {
        it("queue.dequeue", () => {
            const q = new Queue();
            expect(() => q.dequeue()).toThrow("Can not remove from an empty queue.");
        });

        it("queue.first", () => {
            const q = new Queue();
            expect(() => q.first()).toThrow("Can not get first of an empty queue.");
        });

        it("queue.last", () => {
            const q = new Queue();
            expect(() => q.last()).toThrow("Can not get last of an empty queue.");
        });

        it("queue.view", () => {
            const q = new Queue();
            expect(() => q.view()).toThrow("Can not view an empty queue.");
        });
    });
});