stringBuilderClass

describe('Tests sb', function () {
    describe('constructor ', function () {
        it('assert an instance with string param or none', function () {
            let sb = new StringBuilder('test');
            assert.deepEqual(sb._stringArray, ['t', 'e', 's', 't']);
            sb = new StringBuilder('');
            assert.deepEqual(sb._stringArray, []);
            sb = new StringBuilder();
            assert.deepEqual(sb._stringArray, []);
        });

        it('assert an instance with invalid param', function () {
            assert.Throw(
                () => new StringBuilder(8),
                'Argument must be a string'
            );
        });
    });

    describe('append', function () {
        it('assert append with valid param', function () {
            let sb = new StringBuilder('test');
            sb.append('hi');
            assert.deepEqual(sb._stringArray, ['t', 'e', 's', 't', 'h', 'i']);
        });
        it('assert append with valid param', function () {
            let sb = new StringBuilder('test');
            sb.append('');
            assert.deepEqual(sb._stringArray, ['t', 'e', 's', 't']);
        });
        it('assert an instance with invalid param', function () {
            let sb = new StringBuilder('test');
            assert.Throw(() => sb.append(8), 'Argument must be a string');
        });
        it('assert an instance with invalid param', function () {
            let sb = new StringBuilder('tes');
            assert.Throw(() => sb.append(), 'Argument must be a string');
        });
    });
    describe('prepend', function () {

         it('assert prepend with valid param', function () {
             let sb = new StringBuilder('test');
             sb.prepend('hi');
             assert.deepEqual(sb._stringArray, ['h', 'i','t', 'e', 's', 't']);
         });
         it('assert prepend with valid param', function () {
             let sb = new StringBuilder('test');
             sb.prepend('');
             assert.deepEqual(sb._stringArray, ['t', 'e', 's', 't']);
         });
         it('assert an instance with invalid param', function () {
             let sb = new StringBuilder('test');
             assert.Throw(() => sb.prepend(8), 'Argument must be a string');
         });
         it('assert an instance with invalid param', function () {
             let sb = new StringBuilder('tes');
             assert.Throw(() => sb.prepend(), 'Argument must be a string');
         });
    });
    describe('insertAt', function () {
         it('assert insert with valid param', function () {
             let sb = new StringBuilder('test');
             sb.insertAt('hi', 0);
             assert.deepEqual(sb._stringArray, ['h', 'i', 't', 'e', 's', 't']);
         });
         it('assert insert with valid param', function () {
             let sb = new StringBuilder('test');
             sb.insertAt('', 2);
             assert.deepEqual(sb._stringArray, ['t', 'e', 's', 't']);
         });
         it('assert an instance with invalid param', function () {
             let sb = new StringBuilder('test');
             assert.Throw(() => sb.insertAt(8, 2), 'Argument must be a string');
         });
         it('assert an instance with invalid param', function () {
             let sb = new StringBuilder('tes');
             assert.Throw(() => sb.insertAt(null, 0), 'Argument must be a string');
         });
         it('assert an instance with invalid param', function () {
             let sb = new StringBuilder('tes');
             assert.Throw(
                 () => sb.insertAt(),
                 'Argument must be a string'
             );
         });
    });
    describe('remove', function () {
        it('assert remove with valid param', function () {
            let sb = new StringBuilder('test');
            sb.remove(0, 0);
            assert.deepEqual(sb._stringArray, ['t', 'e', 's', 't']);
        });
        it('assert remove with valid param', function () {
            let sb = new StringBuilder('test');
            sb.remove(1, 2);
            assert.deepEqual(sb._stringArray, ['t', 't']);
        });
    });
    describe('toString', function () {
        it('assert output string', function () {
            let sb = new StringBuilder('test');
            sb.remove(1, 2);
            assert.equal(sb.toString(), 'tt')
        });

        it('assert output string', function () {
            let sb = new StringBuilder('test');
            sb.insertAt('hi', 2);
            assert.equal(sb.toString(), 'tehist');
        });
        it('assert output string', function () {
            let sb = new StringBuilder('test');
            sb.remove(2, 2);
            assert.equal(sb.toString(), 'te');
        });
    });
});