fixed-array.test.ts

import { FixedArray } from ".";

test("accepts a size", () => {
    const arr = new FixedArray(5);
    expect(arr.size()).toBe(5);
});

test("holds elements", () => {
    const arr = new FixedArray(2);
    arr.set(0, "Hello");
    arr.set(1, "World");
    expect(arr.get(0)).toBe("Hello");
    expect(arr.get(1)).toBe("World");
});

test("can create copies", () => {
    const arr = new FixedArray(2);
    arr.set(0, "Hello");
    arr.set(1, "World");
    const cp = arr.copy(3);
    expect(cp.size()).toBe(3);
    for (const el of arr)
        expect(cp["_array"].includes(el));
});

test("doesn't accept initial size of less than one", () => {
    expect(() => new FixedArray(0)).toThrowError(RangeError);
});

test("doesn't allow indexing out of bounds", () => {
    const arr = new FixedArray(5);
    expect(() => arr.get(-1)).toThrowError(ReferenceError);
    expect(() => arr.get(99)).toThrowError(ReferenceError);
    expect(() => arr.set(-1, 5)).toThrowError(ReferenceError);
    expect(() => arr.set(99, 5)).toThrowError(ReferenceError);
});

test("doesn't allow creating a smaller copy", () => {
    expect(() => (new FixedArray(5)).copy(4)).toThrowError(RangeError);
});

test("default value is set", () => {
    const arr = new FixedArray(50, "test");
    for (let i = 0; i < 50; i++)
        expect(arr.get(i)).toBe("test");
});

test("changeWithFn method changes elements like dictated by the second argument", () => {
    const arr = new FixedArray(50, 0);
    for (let i = 0; i < 50; i++)
        arr.changeWithFn(i, () => i);
    for (let i = 0; i < 50; i++)
        expect(arr.get(i)).toBe(i);
    for (let i = 0; i < 50; i++)
        arr.changeWithFn(i, x => x / 2);
    for (let i = 0; i < 50; i++)
        expect(arr.get(i)).toBe(i / 2);
});