Utils.test.ts

import { getStringInfo, StringUtils, toUpperCase } from "../app/Utils";


describe('Utils test suite', () => {

    describe.only('StringUtils tests', ()=>{

        let sut: StringUtils;

        beforeEach(()=>{
            sut = new StringUtils();
        })

        it('Should return correct upperCase', ()=>{
            const actual = sut.toUpperCase('abc');
            expect(actual).toBe('ABC');
        })

        it('Should throw error on invalid argument - function', ()=>{
            function expectError() {
                const actual = sut.toUpperCase('');
            }            
            expect(expectError).toThrow();
            expect(expectError).toThrowError('Invalid argument!');
        })

        it('Should throw error on invalid argument - arrow function', ()=>{      
            expect(()=>{
                sut.toUpperCase('');
            }).toThrowError('Invalid argument!');
        })

        it('Should throw error on invalid argument - try catch block', (done)=>{             
            try {
                sut.toUpperCase('');
                done('GetStringInfo should throw error for invalid arg!')
            } catch (error) {
                expect(error).toBeInstanceOf(Error);
                expect(error).toHaveProperty('message', 'Invalid argument!');
                done();
            }

        })

    });








    it('should return uppercase of valid string', () => {
        const sut = toUpperCase;
        const expected = 'ABC'

        const actual = sut('abc');

        expect(actual).toBe(expected);
    })

    describe('ToUpperCase examples', ()=>{
        it.each([
            {input:'abc', expected: 'ABC'},
            {input:'My-String', expected: 'MY-STRING'},
            {input:'def', expected: 'DEF'}
        ])('$input toUpperCase should be $expected', ({input, expected})=>{
            const actual = toUpperCase(input);
            expect(actual).toBe(expected);
        });
    })

    describe('getStringInfo for arg My-String should', ()=>{

        
        test('return right length', ()=>{
            const actual = getStringInfo('My-String');
            expect(actual.characters).toHaveLength(9);
        });
        test('return right lower case', ()=>{
            const actual = getStringInfo('My-String');
            expect(actual.lowerCase).toBe('my-string');
        });
        test('return right upper case', ()=>{
            const actual = getStringInfo('My-String');
            expect(actual.upperCase).toBe('MY-STRING');
        });
        test('return right characters', ()=>{
            const actual = getStringInfo('My-String');
            expect(actual.characters).toEqual(['M', 'y', '-','S', 't', 'r','i', 'n', 'g']);
            expect(actual.characters).toContain<string>('M');
            expect(actual.characters).toEqual(
                expect.arrayContaining(['S', 't', 'r','i', 'n', 'g', 'M', 'y', '-'])
            );
        });
        test('return defined extra info', ()=>{
            const actual = getStringInfo('My-String');
            expect(actual.extraInfo).toBeDefined();
        });

        test('return right extra info', ()=>{
            const actual = getStringInfo('My-String');
            expect(actual.extraInfo).toEqual({})
        });

    });
});