swaf/test/Pagination.test.ts

import Pagination from "../src/Pagination";

describe('Pagination', () => {
    const pagination = new Pagination(3, 5, 31);
    test('Should have correct page', () => {
        expect(pagination.page).toBe(3);
    });
    test('Should have correct perPage', () => {
        expect(pagination.perPage).toBe(5);
    });
    test('Should have correct totalCount', () => {
        expect(pagination.totalCount).toBe(31);
    });


    // Parameter validation
    test('Invalid perPage should throw', () => {
        expect(() => {
            new Pagination(1, 0, 5);
        }).toThrow('perPage must be >= 1');
        expect(() => {
            new Pagination(1, -1, 5);
        }).toThrow('perPage must be >= 1');
        expect(() => {
            new Pagination(1, -5, 5);
        }).toThrow('perPage must be >= 1');
    });
    test('Invalid totalCount should throw', () => {
        expect(() => {
            new Pagination(1, 5, -1);
        }).toThrow('totalCount must be >= 0');
        expect(() => {
            new Pagination(2, 5, -5);
        }).toThrow('totalCount must be >= 0');
    });
    test('Should throw on out of bound creation attempt', () => {
        expect(() => {
            new Pagination(-1, 5, 15);
        }).toThrow('Page -1 not found.');
        expect(() => {
            new Pagination(-20, 5, 15);
        }).toThrow('Page -20 not found.');
        expect(() => {
            new Pagination(3, 5, 15);
        }).not.toThrow();
        expect(() => {
            new Pagination(4, 5, 15);
        }).toThrow('Page 4 not found.');
        expect(() => {
            new Pagination(20, 5, 15);
        }).toThrow('Page 20 not found.');
    });
    test('Page 1 should not throw with totalCount=0', () => {
        expect(() => {
            new Pagination(1, 5, 0);
        }).not.toThrow();
        expect(() => {
            new Pagination(2, 5, 0);
        }).toThrow('Page 2 not found.');
    });


    test('Should calculate correct last page', () => {
        expect(new Pagination(3, 5, 30).lastPage).toBe(6);
        expect(new Pagination(3, 5, 31).lastPage).toBe(7);
        expect(new Pagination(3, 5, 32).lastPage).toBe(7);
        expect(new Pagination(3, 5, 34).lastPage).toBe(7);
        expect(new Pagination(3, 5, 35).lastPage).toBe(7);
        expect(new Pagination(3, 5, 36).lastPage).toBe(8);

        expect(new Pagination(1, 5, 0).lastPage).toBe(1);
    });

    test('Should properly tell whether has a previous page', () => {
        expect(pagination.hasPrevious()).toBe(true);
        expect(new Pagination(1, 5, 15).hasPrevious()).toBe(false);
        expect(new Pagination(2, 5, 15).hasPrevious()).toBe(true);
        expect(new Pagination(3, 5, 15).hasPrevious()).toBe(true);

        expect(new Pagination(1, 5, 17).hasPrevious()).toBe(false);
        expect(new Pagination(2, 5, 17).hasPrevious()).toBe(true);
        expect(new Pagination(3, 5, 17).hasPrevious()).toBe(true);
        expect(new Pagination(4, 5, 17).hasPrevious()).toBe(true);
    });

    test('Should properly tell whether has a next page', () => {
        expect(pagination.hasPrevious()).toBe(true);
        expect(new Pagination(1, 5, 15).hasNext()).toBe(true);
        expect(new Pagination(2, 5, 15).hasNext()).toBe(true);
        expect(new Pagination(3, 5, 15).hasNext()).toBe(false);

        expect(new Pagination(1, 5, 17).hasNext()).toBe(true);
        expect(new Pagination(2, 5, 17).hasNext()).toBe(true);
        expect(new Pagination(3, 5, 17).hasNext()).toBe(true);
        expect(new Pagination(4, 5, 17).hasNext()).toBe(false);
    });

    test('Should generate proper previous pages with context', () => {
        expect(new Pagination(1, 1, 100).previousPages(1)).toStrictEqual([]);
        expect(new Pagination(1, 1, 100).previousPages(2)).toStrictEqual([]);
        expect(new Pagination(1, 1, 100).previousPages(3)).toStrictEqual([]);

        expect(new Pagination(2, 1, 100).previousPages(1)).toStrictEqual([1]);
        expect(new Pagination(2, 1, 100).previousPages(2)).toStrictEqual([1]);
        expect(new Pagination(2, 1, 100).previousPages(3)).toStrictEqual([1]);

        expect(new Pagination(3, 1, 100).previousPages(1)).toStrictEqual([1, 2]);
        expect(new Pagination(3, 1, 100).previousPages(2)).toStrictEqual([1, 2]);
        expect(new Pagination(3, 1, 100).previousPages(3)).toStrictEqual([1, 2]);

        expect(new Pagination(10, 1, 100).previousPages(1)).toStrictEqual([1, -1, 9]);
        expect(new Pagination(10, 1, 100).previousPages(2)).toStrictEqual([1, 2, -1, 8, 9]);
        expect(new Pagination(10, 1, 100).previousPages(3)).toStrictEqual([1, 2, 3, -1, 7, 8, 9]);
    });

    test('Should generate proper next pages with context', () => {
        let pagination = new Pagination(100, 1, 100);
        expect(pagination.nextPages(1)).toStrictEqual([]);
        expect(pagination.nextPages(2)).toStrictEqual([]);
        expect(pagination.nextPages(3)).toStrictEqual([]);

        pagination = new Pagination(99, 1, 100);
        expect(pagination.nextPages(1)).toStrictEqual([100]);
        expect(pagination.nextPages(2)).toStrictEqual([100]);
        expect(pagination.nextPages(3)).toStrictEqual([100]);

        pagination = new Pagination(98, 1, 100);
        expect(pagination.nextPages(1)).toStrictEqual([99, 100]);
        expect(pagination.nextPages(2)).toStrictEqual([99, 100]);
        expect(pagination.nextPages(3)).toStrictEqual([99, 100]);

        pagination = new Pagination(90, 1, 100);
        expect(pagination.nextPages(1)).toStrictEqual([91, -1, 100]);
        expect(pagination.nextPages(2)).toStrictEqual([91, 92, -1, 99, 100]);
        expect(pagination.nextPages(3)).toStrictEqual([91, 92, 93, -1, 98, 99, 100]);
    });
});